Access groupA set of rules that can be configured once and then quickly applied across many Access applications.Cloudflare One
accountAccounts group one or more members together with specific roles or permissions. Accounts can be associated with any number of domains.Fundamentals
ACK (Acknowledge)The final step in the TCP three-way handshake, confirming the establishment of a connection.Spectrum
active zoneA DNS zone that is active on Cloudflare requires changing its nameservers to Cloudflare’s for management.Cloudflare One, DNS
address mapA data structure enabling customers with BYOIP prefixes or account-level static IPs to specify which IP addresses should be mapped to a zone’s DNS records when they are proxied through Cloudflare.BYOIP
alarmA Durable Object alarm is a mechanism that allows you to schedule the Durable Object to be woken up at a time in the future.Durable Objects
allowlistAn allowlist is a list of items (usually websites, IP addresses, email addresses, etc.) that are permitted to access a system.DDoS Protection, WAF
anycastAnycast is a network addressing and routing method in which incoming requests can be routed to a variety of different locations. Anycast typically routes incoming traffic to the nearest data center with the capacity to process the request efficiently.Magic Transit, Magic WAN
apex domainApex domain is used to refer to a domain that does not contain a subdomain part, such as (without www.). It is also known as “root domain” or “naked domain”.DNS
API callAlso known as an API request. An API call is a message sent to a server asking an API to provide a service or information.API Shield
API endpointThe API endpoint is the location where API calls or requests are fulfilled. API Shield defines endpoints as a host, method, and path tuple.API Shield
API keyAn API key is unique to each Cloudflare user and used to confirm identity when using the Cloudflare API.Fundamentals
API schemaThe API schema defines which API requests are valid based on several request properties like target endpoint, path or query variable format, and HTTP method.API Shield
API tokenAPI tokens authorize access to specific Cloudflare dashboard pages, accounts, and zones. API tokens are associated to the user that created them.Fundamentals
App LauncherThe App Launcher portal provides end users with a single dashboard to open applications secured by Cloudflare Zero Trust.Cloudflare One
applicationThe resource protected by Cloudflare Zero Trust, which can be a subdomain, a path, or a SaaS application.Cloudflare One
application tokenA piece of data that grants a user access to a specific Access application for a period of time. Can be stored in a browser cookie or passed to the application in place of a normal password.Cloudflare One
attack scoreA number from 1 (likely malicious) to 99 (likely clean) classifying how likely an incoming request is malicious or not. Allows you to detect new attack techniques before they are publicly known.WAF
attributeTraffic that flows through Area 1 can receive one or more attributes, which indicate that a specific condition has been met.Area 1
Authenticated Origin PullsAuthenticated Origin Pulls allow origin web servers to validate that a web request came from Cloudflare using TLS client certificate authentication.Cloudflare One, SSL/TLS
autonomous system numbers (ASNs)A large network or group of networks that has a unified routing policy. Every computer or device that connects to the Internet is connected to an autonomous system.BYOIP, Magic WAN
Auxiliary WorkerA Worker created locally via the Workers Vitest integration that runs in a separate isolate to the test runner, with a different global scope.Workers
backup codesBackup codes allow restoration of Cloudflare account access outside the normal two-factor authentication process. A backup code becomes invalid after use.Fundamentals
bandwidthThe maximum rate of data transfer across a network.Speed
bindingBindings allow your Workers to interact with resources on the Cloudflare Developer Platform.Workers
bit field matchingMatches raw bits in a packet to certain values specified in your rules.Magic Firewall
blocklistA blocklist is a list of items (usually websites, IP addresses, email addresses, etc.) that are prevented from accessing a system.WAF
Border Gateway Protocol (BGP)The routing protocol for the Internet, which is responsible for picking the most efficient routes to deliver Internet traffic.BYOIP
botA software application programmed to do tasks that can be used for good (chatbots, search engine crawlers) or for evil (inventory hoarding, credential stuffing).Bots
bot scoreA score from 1 to 99 that indicates how likely that request came from a bot, in which 1 to 29 is likely automated and 30 to 99 is likely human.Bots
bot tagsAdditional information about a bot request, such as why Cloudflare has given it a bot score and whether the request came from a verified bot or a category of verified bots.Bots
brotli compressionBrotli compression is a data compression algorithm developed by Google, optimized for web content, and designed to achieve higher compression ratios than traditional algorithms like Gzip.Speed
C3C3 is a command-line tool designed to help you set up and deploy new applications to Cloudflare.Workers
cacheA temporary storage area where frequently accessed data is stored for quick retrieval.Cache
cache hitWhen a requested piece of content is found in the cache, reducing the need to fetch it from the origin server.Cache
cache lockCache lock (or mutex) is a mechanism employed by CDN data centers, comprising numerous servers, to prevent the overloading of origin servers. This mechanism ensures that only one server can request a specific file from the origin at any given time, facilitating efficient coordination among the servers.Cache
cache missWhen a requested piece of content is not found in the cache, requiring the server to fetch it from the origin server.Cache
cached bandwidth (cached egress bandwidth)The amount of bandwidth served from Cloudflare without hitting the origin server. Cached bandwidth is the sum of all EdgeResponseBytes where CacheCacheStatus equals hit, stale, updating, ignored, or revalidated.Cache
cached requestsThe number of requests served from Cloudflare without having to hit the origin server. Cached requests are the sum of all requests where CacheCacheStatus equals hit, stale, updating, ignored. This does not include revalidated since the request had to be sent to the origin server.Cache
cacheTtlCacheTtl is a parameter that defines the length of time in seconds that a KV result is cached in the global network location it is accessed from.KV
cachingThe process of storing copies of files or data in a cache to accelerate future requests.Cache
CAPTCHAA CAPTCHA test is designed to determine if an online user is really a human and not a bot. CAPTCHA is an acronym that stands for “Completely Automated Public Turing test to tell Computers and Humans Apart.”Turnstile
captive portalA login screen shown to users when they connect to a public Wi-Fi. Captive portals typically occur in places such as airports, cafes, and hotels.Cloudflare One
certificateSSL certificates enable encryption over HTTPS for traffic between a client and a website. SSL certificates contain the website’s public key and the website’s identity along with related information. Devices attempting to communicate with the origin web server reference the SSL certificate to obtain the public key and verify the server’s identity. Cloudflare provides a Universal SSL certificate for each active Cloudflare domain.SSL/TLS
Certificate Authority (CA)A CA is a trusted third party that provides SSL certificates for encrypting network traffic.SSL/TLS
certificate packsCertificate packs allow Cloudflare to fallback to a different SSL certificate for browsers that do not support the latest standards. Certificate packs allow Custom SSL certificates to contain different signature algorithms for the same hostnames listed within the SSL certificate without taking up additional Custom SSL certificate quota for your Cloudflare account.SSL/TLS
certificate pinningA security mechanism used to prevent on-path attacks on the Internet by hardcoding information about the certificate that the application expects to receive. If the wrong certificate is received, even if it is trusted by the system, the application will refuse to connect.SSL/TLS
Certification Authority Authorization (CAA) recordA CAA record declares which CAs are allowed to issue an SSL certificate for a domain.SSL/TLS
CGNAT IPA unique, virtual IP address assigned to each WARP device from the range. You can view the CGNAT IP for a device on its My Team > Devices page.Cloudflare One
Challenge Solve Rate (CSR)The percentage of issued challenges that were solved.Bots
CIDRCIDR stands for Classless Inter-Domain Routing. CIDR often refers to CIDR notation, which is an IP address represented as a series of four 8-bit octets, separated by dots (e.g., Additionally, CIDR notation includes a suffix that indicates the number of bits used for the network portion of the address. The format is typically written as “/X,” where X is the number of bits in the network portion.Fundamentals
cipher suiteA set of encryption algorithms for establishing a secure communications connection. There are several cipher suites in wide use, and a client and server agree on the cipher suite to use when establishing the TLS connection. Support of multiple cipher suites allows compatibility across various clients.Cloudflare One, SSL/TLS
cloudA network of remote servers used to store and maintain data.Fundamentals
Cloudflare AccessCloudflare Access replaces corporate VPNs with Cloudflare’s network. It verifies attributes such as identity and device posture to grant users secure access to internal tools.Cloudflare One
Cloudflare Browser IsolationCloudflare Browser Isolation seamlessly executes active webpage content in a secure isolated browser to protect users from zero-day attacks, malware, and phishing.Cloudflare One
Cloudflare CASBCloudflare CASB provides comprehensive visibility and control over SaaS apps to prevent data leaks and compliance violations. It helps detect insider threats, shadow IT, risky data sharing, and bad actors.Cloudflare One
Cloudflare Data Loss Prevention (DLP)Cloudflare Data Loss Prevention (DLP) allows you to scan your web traffic and SaaS applications for the presence of sensitive data such as social security numbers, financial information, secret keys, and source code.Cloudflare One
Cloudflare DEXCloudflare Digital Experience Monitoring (DEX) provides visibility into device, network, and application performance across your Zero Trust organization.Cloudflare One
Cloudflare GatewayCloudflare Gateway is a modern next-generation firewall between your user, device, or network and the public Internet. It includes DNS filtering to inspect and apply policies to all Internet-bound DNS queries.Cloudflare One
Cloudflare One AgentThe name of the Cloudflare WARP client app on iOS and Android devices.Cloudflare One
Cloudflare TunnelCloudflare Tunnel uses software agents (cloudflared or WARP Connector) to establish a secure connection between a private network and Cloudflare.Cloudflare One
Cloudflare Zero TrustCloudflare Zero Trust provides the power of Cloudflare’s global network to your internal teams and infrastructure. It empowers users with secure, fast, and seamless access to any device on the Internet.Cloudflare One
cloudflaredThe software powering Cloudflare Tunnel. It runs on origin servers to connect applications or private networks to Cloudflare.Cloudflare One
cloudflared replicaAn additional instance of cloudflared that points to the same Cloudflare Tunnel. It ensures that your network remains online in case a single host running cloudflared goes down.Cloudflare One
code exampleA code example illustrates how to use a programming element to implement specific functionalityFundamentals
compressionThe process of reducing the size of files or data to speed up their transfer over the network.Speed
consumerA consumer is the term for a client that is subscribing to or consuming messages from a queue.Queues
content delivery network (CDN)A geographically distributed group of servers which work together to provide fast delivery of Internet content.Cache, DDoS Protection, Fundamentals
content objectA content object is any binary part of a request body (as detected by Cloudflare systems) that does not match any of the following content types: text/html, text/x-shellscript, application/json, text/csv, or text/xml.WAF
content security policy (CSP)An added layer of security that helps detect and mitigate certain types of attacks such as cross-site scripting (XSS) attacks.Fundamentals
core web vitalsCore web vitals are a set of user-centric performance metrics, including Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and First Input Delay (FID), used by Google to assess the overall user experience of a webpage.Speed
CPU timeCPU time is the amount of time the central processing unit (CPU) actually spends doing work, during a given request.Workers
credential stuffingCredential stuffing is the automated injection of stolen username and password pairs (known as “credentials”) into website login forms, trying to gain access to user accounts.WAF
creditAn amount applied to a specific Cloudflare account as credit for recurring subscriptions or plan payments. The Cloudflare billing system automatically applies credits in the next billing cycle.Fundamentals
Cron TriggersCron Triggers allow users to map a cron expression to a Worker using a scheduled() handler that enables Workers to be executed on a schedule.Workers
cumulative layout shift (CLS)Cumulative layout shift (CLS) is a web performance metric that quantifies the visual stability of a webpage by measuring the sum of unexpected layout shifts of elements during the page’s loading and rendering process.Speed
D1D1 is Cloudflare’s native serverless database.D1, Workers
daemonA program that performs tasks without active management or maintenance.Cloudflare One, DDoS Protection
data centerA physical location where servers run and other IT operations are hosted.Fundamentals
data packetA data packet is a unit of data consisting of user and control information. Information in a network is broken down into packets, that might follow different paths to their final destination.Magic Firewall, Magic Transit, Magic WAN
debuggingThe process of identifying and resolving errors or issues within software applications or systems, often facilitated by analyzing log data.Logs
demo applicationA demo application is a functional application in GitHub that you can clone and deploy on your own.Fundamentals
denial-of-service (DoS) attackA DoS attack is a type of cyber attack in which an attacker aims to render a computer or other device unavailable to its intended users by interrupting the device’s normal functioning.Fundamentals
deploymentDeployments track the version(s) of your Worker that are actively serving traffic.Workers
deprecationDeprecation in software development involves officially labeling a feature as outdated. While a deprecated software feature remains within the software, users are warned and encouraged to adopt alternatives. Eventually, deprecated features may be removed. This approach ensures backward compatibility and gives programmers time to update their code.Logs
detection IDStatic rules that are used to detect predictable bot behavior with no overlap with human traffic.Bots
device postureA way to evaluate the security of a user’s device, for example by verifying its serial number or checking if it has the latest software updates.Cloudflare One
device profileA collection of WARP client settings applied to a specific set of devices in your organization.Cloudflare One
dispositionRepresents Area 1’s evaluation of a specific message. For example, after evaluating an email it may get a disposition of malicious. Email messages with this disposition exhibit characteristics typical of malicious emails.Area 1
distributed denial-of-service (DDoS) attackA DDoS attack is a malicious attempt to disrupt normal traffic of a targeted server, service, or network by overwhelming the target or its surrounding infrastructure with a flood of Internet traffic.DDoS Protection, Fundamentals, Magic Network Monitoring
DNS filteringDNS filtering uses the Domain Name System to block malicious websites and filter out harmful content, enhancing security and access control.Cloudflare One, DNS
DNS locationDNS locations are a collection of DNS endpoints which can be mapped to physical entities such as offices, homes, or data centers.Cloudflare One, DNS
DNS over HTTPSDNS over HTTPS (DoH) is a standard for encrypting DNS traffic via the HTTPS protocol, preventing tracking and spoofing of DNS queries., Cloudflare One, DNS
DNS over TLSDNS over TLS (DoT) is a standard for encrypting DNS traffic using its own port (853) and TLS encryption., Cloudflare One, DNS
DNS recordDNS records are instructions that live in authoritative DNS servers and provide information about a domain including what IP address is associated with that domain and how to handle requests for that domain.DNS
DNS serverDNS servers translate human-readable domain names into IP addresses, eliminating the need to remember complex IP addresses.Cloudflare One, DNS
DNS zoneA portion of the DNS namespace that is managed by a specific organization or administrator.DNS
DoH subdomainA unique DoH subdomain for each DNS location in Cloudflare Zero Trust used in WARP client settings.Cloudflare One
domainThe domain name of your application on Cloudflare.Fundamentals
domain control validation (DCV)Process by which a certificate authority (CA) can verify domain ownership before issuing an SSL/TLS certificate.SSL/TLS
Domain Name System (DNS)The Domain Name System (DNS) is the phonebook of the Internet. DNS translates domain names to IP addresses.DNS
downtimeDowntime is the duration during which a system, service, or equipment is not operational or unavailable for use.Waiting Room
Durable ObjectsDurable Objects is a globally distributed coordination API with strongly consistent storage.Durable Objects, Workers
durationDuration is a measurement of wall-clock time — the total amount of time from the start to end of an invocation of a Worker.Workers
dynamic contentDynamic content refers to website content that changes based on factors specific to the user such as time of visit, location, and device. News websites or social media are examples of this type of content. For this type of website, content has to be fetched from the origin server every time it is requested.Cache
edge certificate

The SSL/TLS certificates that Cloudflare presents to clients visiting your website or application.

Because of how Cloudflare works, there can actually be two certificates involved in a single request: an edge certificate and an origin certificate.

edge response status codeHTTP response code sent from Cloudflare to the client (end user). The Cloudflare dashboard Analytics app uses the edge response status code.Fundamentals
edge serverA server located at the edge of a network, typically within a CDN, that serves content to end-users.Cache, Logs
EDNS Client Subnet (ECS)

ECS is a DNS extension that enables recursive DNS resolvers to include client IP address information in their DNS queries.

Not all resolvers use ECS but, if they do, usually a part of the IP address is omitted. Sending ECS headers is generally intended to reduce latency and speed up content delivery in connection to CDNs and load balancers. The ECS mechanism is specified in RFC 7871. (DNS Resolver), Cloudflare One, DNS, Load Balancing
encryption algorithmAn encryption algorithm is a set of mathematical operations performed on data to ensure the data is only understood by the intended recipient.SSL/TLS

Any service or hardware that intercepts and processes incoming public or private traffic.

Examples of endpoints include origins, hostnames, private or public IP addresses, virtual IP addresses (VIPs), servers, and other dedicated hardware boxes.

Load Balancing
environmentEnvironments allow you to deploy the same Worker application with different configuration for each environment. Only available for use with wrangler.toml.Workers
environment variableEnvironment variables are a type of binding that allow you to attach text strings or JSON values to your Worker.Workers
equal-cost multi-path routingA technique that uses hashes calculated from packet data to determine the route chosen.Magic Transit, Magic WAN
error pageAn error page is a webpage shown to users when they try to access a specific webpage or resource that is unavailable due to a server error, broken link, or other issues. It typically includes details about the encountered error and offers potential solutions or guidance to help users navigate the problem.Waiting Room
eventAn occurrence or happening that is significant and worthy of being recorded in a log.Logs
exposed credentials

Exposed credentials refers to sensitive authentication information disclosed in some way (for example, due to misconfigurations, data breaches, or simple human error), allowing other parties to gain access to digital resources.

Credentials may include usernames, passwords, API keys, authentication tokens, or private keys.

Extended Validation (EV) certificateEV certificates provide maximum trust to visitors, but require the most validation effort by the CA. EV certificates show the name of the company or organization in the address bar of the visitor’s browser. An EV certificate requires additional documentation by the company or organization in order for the CA to approve the certificate.SSL/TLS
featureA feature is a setting in the Cloudflare dashboard that corresponds to functionality within a Cloudflare product or API.Fundamentals
firewallA firewall is a security system that monitors and controls network traffic based on a set of security rules.Magic Firewall, WAF
firewall-as-a-serviceAlso known as cloud firewall. A security product that is hosted in the cloud.Magic Firewall
first contentful paint (FCP)First contentful paint (FCP) is a web performance metric that measures the time it takes for the first piece of content to be rendered on the screen during the loading of a web page.Speed
first input delay (FID)First input delay (FID) is a web performance metric that measures the delay between a user’s first interaction with a page (for example, clicking a button) and the moment the browser responds, indicating the page’s interactivity and responsiveness.Speed
flow dataRepresents records of communication between devices. There are a number of flow data protocols, such as NetFlow or sFlow.Magic Network Monitoring
FTP (File Transfer Protocol)A standard network protocol used for transferring files from one host to another over a TCP-based network.Spectrum
FTPS (File Transfer Protocol Secure)An extension of FTP that adds support for the Transport Layer Security (TLS) or Secure Sockets Layer (SSL) cryptographic protocols.Spectrum
GRE tunnelStands for generic routing encapsulation. It is a protocol wrapping one data packet within another type of data packet. This is useful for enabling protocols that are not normally supported by a network.Magic Transit, Magic WAN
handlerHandlers are methods on Workers that can receive and process external inputs, and can be invoked from outside your Worker.Workers
health check

Requests issued by a monitor at regular interval and — depending on the monitor settings — return a pass or fail value to make sure an endpoint is still able to receive traffic.

Each health monitor request is trying to answer two questions:

  1. Is the endpoint offline?: Does the endpoint respond to the health monitor request at all? If so, does it respond quickly enough (as specified in the monitor’s Timeout field)?
  2. Is the endpoint working as expected?: Does the endpoint respond with the expected HTTP response codes? Does it include specific information in the response body?

If the answer to either of these questions is “No”, then the endpoint fails the health monitor request.

Load Balancing
hostnameThe name given to a server or node on a network, often the public DNS name of a server.Cloudflare One, DDoS Protection, DNS
HTTP requestAn HTTP request is the way Internet communications platforms such as web browsers ask for the information they need to load a website.Fundamentals, Logs
ICMPInternet Control Message Protocol (ICMP) is used by network devices to send error messages and other operational information. ICMP is useful for diagnostic purposes, for example.DDoS Protection, Magic Transit, Magic WAN
identity providerAn identity provider (IdP) stores and manages users’ digital identities, enabling single sign-on and authentication for multiple applications.Cloudflare One
idle connectionWhen a TCP connection is in an idle state, it means that the connection has been established, but neither endpoint is sending any data. In the context of HTTP, an idle connection is when an established connection between a client and a server is not currently transmitting any HTTP requests or responses.Fundamentals
iFrameAn iFrame, short for Inline Frame, is an HTML element used to embed and display external content within a webpage, allowing the incorporation of another document or web page seamlessly within the main document.Waiting Room
interaction to next paint (INP)Interaction to next paint (INP) is a web performance metric that measures the time it takes for a web page to become interactive and respond to user input after the initial paint, providing insights into the user experience during the interaction phase of page loading.Speed
intermediate certificateFor security purposes, CAs issue intermediate certificates for signing website certificates. Intermediate certificates provide a means for the CA to revoke a single intermediate certificate, thus affecting only a small subset of website certificates.SSL/TLS
InternetThe Internet is a global system of computer networks that provides a wide range of information and communication facilities.Fundamentals
Internet key exchange (IKE)The protocol Cloudflare uses to create the IPsec tunnel between Magic WAN and the customer’s device.Magic Transit, Magic WAN
Internet Routing Registry (IRR)A globally distributed database of routing information which contains announced routes and routing policies in a common format. Network operators use this information to configure backbone routers.BYOIP
IP addressIP stands for Internet Protocol, which is the set of rules that makes it possible for devices to communicate over the Internet. With billions of people accessing the Internet every day, unique identifiers are necessary to keep track of who is doing what. The Internet Protocol solves this by assigning IP numbers to every device accessing the Internet. Every assigned number is an IP address.Fundamentals
IP spoofingIP spoofing is the creation of Internet Protocol (IP) packets which have a modified source address to hide the identity of the sender, impersonate another computer system, or both.DDoS Protection
IPsec tunnelStands for Internet Protocol secure. It is a group of protocols for securing connections between devices, by encrypting IP packets.Magic Transit, Magic WAN
isolateIsolates are lightweight contexts that provide your code with variables it can access and a safe environment to be executed within.Workers
JA3 fingerprintJA3 and JA4 fingerprints profile specific SSL/TLS clients across different destination IPs, Ports, and X509 certificates.Bots
JSON web tokenA compact way to securely transmit information between parties as a JSON object, often used for authentication.Cloudflare One
JSON web token (JWT)A common authentication and authorization method used in web applications and APIs.API Shield, Rules
JSON-friendlyJSON-friendly refers to data or formats that are easily and naturally represented in JSON (JavaScript Object Notation), a lightweight data interchange format, without requiring complex transformations or modifications.Waiting Room
KVWorkers KV is Cloudflare’s key-value data storage.KV, Workers
KV namespaceA KV namespace is a key-value database replicated to Cloudflare’s global network. A KV namespace must require a binding and an id.KV
largest contentful paint (LCP)Largest contentful paint (LCP) is a web performance metric that measures the time it takes for the largest content element to be fully rendered and visible to the user during the loading of a web page.Speed
latencyThe delay between a user action and the corresponding response from the system.Speed
layer 3The network layer in the OSI model, responsible for logical addressing, routing, and forwarding of data between devices on different networks.Spectrum
layer 4The transport layer in the OSI model, managing end-to-end communication, error-checking, and flow control.Spectrum
lazy loadingLoading images or other resources only when they are about to be displayed, rather than loading everything at once.Speed
legitimate trafficLegitimate traffic refers to authorized and permissible network activity, data transmissions, or communications that adhere to established norms and rules within a given system or network.Waiting Room
letter of agencySometimes referred to as a Letter of Authorization. A document that authorizes Cloudflare to advertise your prefixes. This is required so transit providers can accept the routes Cloudflare advertises on your behalf.BYOIP, Magic Transit
locally-managed tunnelA Cloudflare Tunnel that was created by running cloudflared tunnel create <NAME> on the command line. Tunnel configuration is stored in your local cloudflared directory.Cloudflare One
logA chronological record of events, actions, or transactions, typically used for tracking and troubleshooting purposes.Logs
log fileA file containing a collection of log entries, usually stored in a structured or semi-structured format.Logs
loggingThe process of recording events, actions, or transactions in a log.Logs
managed networkA network location, such as an office, that is associated with a specific WARP client device profile.Cloudflare One
maximum segment size (MSS)MSS limits the size of packets, or small chunks of data, that travel across a network, such as the Internet.Magic Transit, Magic WAN
MDM fileA Mobile Device Management (MDM) file is a configuration file that allows organizations to manage the software, settings, and certificates installed on their devices.Cloudflare One
member or userA member or user is an email account in Cloudflare that you can grant access to your organization account. Members belonging to multiple accounts can select which account to manage via the Cloudflare dashboard.Fundamentals
metadataA metadata is a serializable value you append to each KV entry.KV
MFAMulti-factor authentication (MFA) checks multiple aspects of a user’s identity, not only their username and password, before allowing them access to an application.Cloudflare One

A Durable Object migration is a mapping process from a class name to a runtime state. Initiate a Durable Object migration when you need to:

  • Create a new Durable Object class.
  • Rename a Durable Object class.
  • Delete a Durable Object class.
  • Transfer an existing Durable Objects class.
Durable Objects
minificationThe process of removing unnecessary characters from code (such as whitespace or comments) to reduce file size and improve loading times.Speed
mitigated requestA request to which Cloudflare applied a terminating action such as block or challenge.WAF
module WorkerRefers to a Worker written in module syntax.Workers

A monitor issues health monitor requests at regular intervals to evaluate the health of each endpoint within a pool.

When a pool becomes unhealthy, your load balancer takes that pool out of the endpoint rotation.

Load Balancing
MQTT (Message Queuing Telemetry Transport)A lightweight, publish-subscribe messaging protocol often used for communication in the Internet of Things (IoT) and other resource-constrained scenarios.Spectrum
mTLS (mutual TLS)MTLS is a common security practice that uses TLS certificates to ensure that traffic between a client and server is secure and trusted in both directions.API Shield, Cloudflare One, SSL/TLS

A nameserver is a dedicated server that translates human readable hostnames ( into IP addresses.

Nameservers like root servers, TLD servers, and authoritative nameservers are fundamental components of the Domain Name System (DNS).

DDoS Protection, DNS
NetFlowNetwork protocol developed by Cisco to collect and monitor network traffic flow data.Magic Network Monitoring
non-browser trafficNon-browser traffic refers to data exchanges and communication occurring between devices or systems that do not involve web browsers, such as a mobile app or web apps.Waiting Room
OAuthA protocol for authorizing users, allowing them to perform actions and view data on different platforms without sharing credentials.Cloudflare One
OIDCOpenID Connect (OIDC) is an identity authentication protocol built on top of OAuth 2.0. It is used verifying user identity and obtaining basic profile information.Cloudflare One
on-rampRefers to a way of connecting a business network to Cloudflare. Examples of on-ramps, or ways to connect to Cloudflare, are Anycast GRE tunnels, Anycast IPsec tunnels, Cloudflare Network Interconnect (CNI), Cloudflare Tunnel, and WARP.Magic Transit, Magic WAN
Organization Validated (OV) certificateOV certificates are used by corporations or governments to portray an extra layer of confidence for their visitors. Rather than just validating domain ownership, the CA also validates the company’s registration using qualified independent information sources. The organization’s name is listed in the certificate.SSL/TLS
originOrigin generally refers to the web server behind Cloudflare where your application is hosted.Workers
origin bandwidth (origin egress bandwidth)The amount of data transferred from the origin server to Cloudflare within a certain period of time. Origin bandwidth is the sum of all EdgeResponseBytes where OriginResponseStatus does not equal 0.Cache
origin certificateA Cloudflare Origin Certificate is a free SSL/TLS certificate issued by Cloudflare that can be installed on your origin server to facilitate making sure your data is encrypted in transit from Cloudflare to your origin server using HTTPS.Cloudflare One, SSL/TLS
origin requestAn origin request is a request served from the origin server.Fundamentals
origin response status codeAn origin response status code is an HTTP response code sent from the origin server to Cloudflare.Fundamentals
origin serverThe original server where the web content is hosted before it is distributed to edge servers in a CDN.Cache
OSI model (Open Systems Interconnection model)A conceptual framework that standardizes the functions of a telecommunication or computing system into seven abstraction layers.Spectrum
PAC fileA file containing a JavaScript function which can instruct a browser to forward traffic to a proxy server instead of directly to the destination server.Cloudflare One
page load timeThe time it takes for a web page to fully load in a user’s browser.Speed
PagesCloudflare Pages is Cloudflare’s product offering for building and deploying full-stack applications.Pages, Workers
paranoia levelClassifies rules of the OWASP managed ruleset according to their aggressiveness.WAF
partial setupAlso known as CNAME setup, a partial setup allows you to use Cloudflare’s reverse proxy without using Cloudflare for your authoritative nameservers.DNS
phishingThe practice of trying to acquire sensitive data through fraudulent emails or other means. Usually, the perpetrators try to pass for a legitimate company when asking for sensitive data.Area 1
planPlans distinguish the breadth of Cloudflare features accessible to a specific domain. Plan options include Free, Pro, Business, or Enterprise.Fundamentals
policyA set of rules that regulate network activity, such as login access and website reachability.Cloudflare One
policy-based routingPolicy-based routing (PBR) is a technique used to make routing decisions based on policies set by your administrador.Magic Transit, Magic WAN

Within Cloudflare, pools represent your endpoints and how they are organized. As such, a pool can be a group of several endpoints, or you could also have only one endpoint (an origin server, for example) per pool.

If you are familiar with DNS terminology, think of a pool as a “record set,” except Cloudflare only returns addresses that are considered healthy. You can attach health monitors to individual pools for customized monitoring.

Load Balancing

A number that identifies the network portion of an IP address. It tells devices if an IP address is on the same network or not. It is shown as a number after a slash (for example, /31) at the end of the IP address.

Using an analogy, the prefix is like a street address. If an IP is in the same street, it belongs to the same network of devices.

Magic Network Monitoring, Magic Transit, Magic WAN
primary certificate / secondary certificatePrimary and secondary indicates the order in which Custom SSL certificates were uploaded to Cloudflare. The primary certificate is the first certificate added to a pack. The primary certificate defines the hostnames covered by the certificate.SSL/TLS
producerA producer is the term for a client that is publishing or producing messages on to a queue.Queues
protocolA protocol is a set of rules governing the exchange or transmission of data between devices.Fundamentals
proxy protocolA protocol used by network proxies to convey client connection information to the destination server, facilitating proper handling of client requests.Spectrum
proxy read timeoutA proxy read timeout is the maximum amount of time a proxy server waits for a response from the origin server before terminating the connection.Fundamentals
proxy status

The proxy status of a DNS record defines whether requests for your domain will route through Cloudflare (proxied) or not (DNS-only).

When a DNS record is proxied, requests are processed according to your configurations, and Cloudflare can optimize, cache, and protect your domain. Refer to How Cloudflare works for details.

DNS, Fundamentals
proxy write timeoutA proxy write timeout is the maximum amount of time a proxy server allows for sending data to the client before terminating the connection.Fundamentals
public key / private keySSL public and private keys are essentially long strings of characters used for encrypting and decrypting data. Data encrypted with the public key can only be decrypted with the private key, and vice versa. Private keys are kept secret and unshared.SSL/TLS
purgeThe process of removing outdated content from the cache to make room for updated content and ensure the delivery of the latest content.Cache
queueA queue is a buffer or list that automatically scales as messages are written to it, and allows a consumer Worker to pull messages from that same queue.Queues
QueuesQueues integrates with Cloudflare Workers and enables you to build applications that can guarantee delivery.Queues, Workers
R2R2 is an S3-compatible distributed object storage designed to eliminate the obstacles of sharing data across clouds.R2, Workers
rate limitingRate limiting is a technique used in computer systems to control the rate at which requests are processed. It can be used as a security measure to prevent attacks, or to limit resource usage in your origin servers.WAF
RDPRemote Desktop Protocol (RDP) allows remote desktop connections to a computer, often used on Windows and Mac operating systems.Cloudflare One
real user monitoring (RUM)Real user monitoring (RUM) is a web performance monitoring technique that collects and analyzes data based on actual user interactions and experiences, providing insights into how users interact with a website or application in real-time.Speed
redirectURL redirects navigate the user from a source URL to a target URL using a given HTTP status code. URL redirection is also known as URL forwarding.Fundamentals
remotely-managed tunnelA Cloudflare Tunnel that was created in Zero Trust under Networks > Tunnels. Tunnel configuration is stored in Cloudflare, which allows you to manage the tunnel from the dashboard or using the API.Cloudflare One
render timeThe time it takes for a browser to display a fully rendered web page after receiving the necessary resources.Speed
requestA request is a message that is sent between a client, or web browser, to a server. Each request that has been processed through the Cloudflare network generates a record.Fundamentals, Logs
Resource Public Key Infrastructure (RPKI)A cryptographic method of signing records that associate a route with an originating autonomous system number.BYOIP
reverse proxyA server that handles requests on behalf of clients, forwarding them to backend servers and managing tasks like load balancing and security.Spectrum
rolesAuthorize which Cloudflare products and features a member is allowed to access in a Cloudflare account. Learn more about roles.Fundamentals
rollbackRollbacks are a way to deploy an older deployment to the Cloudflare global network.Workers
root certificateA root certificate is generated by a CA and is used to sign certificates. Every browser includes a root store of trusted root certificates. Any certificate signed with the private key of a root certificate is automatically trusted by a browser.Cloudflare One, SSL/TLS
SafeSearchSafeSearch is a feature of search engines that filters explicit or offensive content from search results.Cloudflare One
SAMLSecurity Assertion Markup Language (SAML) enables single sign-on and authentication for multiple applications.Area 1, Cloudflare One
samplingIn the context of Magic Network Monitoring, sampling is the process of taking samples of packets for a specific period to identify potential attacks.Magic Network Monitoring
SASESecure Access Service Edge (SASE) is a cloud-based security model bundling networking and security functions.Cloudflare One
saved bandwidth (saved egress bandwidth)The percentage of bandwidth saved by caching on the Cloudflare network.Cache
SCIMSystem for Cross-domain Identity Management (SCIM) is an open standard protocol that allows identity providers (such as Okta or Microsoft Entra ID) to synchronize user identity information with cloud applications and services.Cloudflare One
search engine optimization (SEO)SEO, or search engine optimization, is the practice of optimizing online content to improve its visibility and ranking in search engine results, thereby increasing organic traffic and relevance.Speed
seatA unique user authenticating to an Access application or enrolling in WARP,Cloudflare One
secretSecrets are a type of binding that allow you to attach encrypted text values to your Worker.Workers
secret keyThe secret key allows communication between your application backend and the Cloudflare Turnstile server to validate the widget response.Turnstile
Secure Sockets Layer (SSL)SSL was a widely used cryptographic protocol for providing data security for Internet communications. SSL was superseded by TLS; however, most people still refer to Internet cryptographic protocols as SSL.SSL/TLS
SEO crawlersSEO crawlers, or web crawlers, are automated programs employed by search engines to systematically browse and index web content, gathering information about the structure and relevance of pages to determine search result rankings.Waiting Room
Server Name Indication (SNI)

SNI allows a server to host multiple TLS Certificates for multiple websites using a single IP address. SNI adds the website hostname in the TLS handshake to inform the server which website to present when using shared IPs.

Cloudflare uses SNI for all Universal SSL certificates.

server response timeThe time it takes for a server to respond to a request from a user’s browser.Speed
Service Level Agreement (SLA)An SLA is a contractual obligation for Cloudflare to maintain a specific level of service. Read the Service Level Agreement (SLA) for the Cloudflare Business plan. Enterprise customers refer to the Enterprise SLA provided with their contract.Fundamentals
service provider (SP)A service provider (SP) provides federated access to an application for a user from an identity provider (IdP).Cloudflare One
service tokenAuthentication credentials generated by Cloudflare Access which enable automated systems to access protected applications.Cloudflare One
service WorkerRefers to a Worker written in service worker syntax.Workers
sessionAn event generated when a user logs in to an Access application.Cloudflare One
session identifierA session identifier is a unique number that a website assigns to identify a specific user for the duration of their visit.API Shield
Set-CookieSet-Cookie is an HTTP header used by web servers to send a cookie to a user’s browser during an HTTP response, enabling the server to store information on the client side, often used for session management and user preferences.Cache, Waiting Room
sFlowAn industry standard packet sampling protocol to monitor network devices.Magic Network Monitoring
SFTP (Secure File Transfer Protocol)A secure file transfer protocol that uses the Secure Socket Shell (SSH) protocol for encryption and authentication.Spectrum
shadow IT

Shadow IT is the unsanctioned use of software, hardware, or other systems and services within an organization, often without the knowledge of that organization’s information technology (IT) department.

For more information, refer to the Cloudflare Learning Center.

Cloudflare One
SIEMA Security Information and Event Management (SIEM) solution collects, analyzes, and correlates data to help manage security incidents, detect anomalies, and meet compliance requirements.Area 1, Cloudflare One, WAF
sitekeyThe sitekey is used to invoke Turnstile on your site.Turnstile
SMBSecure Messaging Block (SMB) is a network file sharing protocol used for accessing files and services on a network.Cloudflare One
SMTPStands for Simple Mail Transfer Protocol. It is an Internet standard based on TCP/IP to send and receive email.Area 1
SMTP Server (Simple Mail Transfer Protocol Server)A server responsible for sending, receiving, and relaying email messages over a network, following the SMTP protocol.Spectrum
source endpointThe source endpoint is the endpoint managed by API Shield in Endpoint Management by its routing feature.API Shield
speed indexSpeed index is a web performance metric that quantifies how quickly a user perceives a webpage to load by measuring the visual progression of content rendering over time, providing a comprehensive assessment of the overall user experience during page loading.Speed
SSHSecure Shell (SSH) protocol allows users to connect to infrastructure remotely and execute commands.Cloudflare One
SSOSingle Sign-On (SSO) is a technology that combines multiple application logins into one, requiring users to enter credentials only once.Cloudflare One
static contentStatic content, like images, stylesheets, and JavaScript, remains the same for all users. It can be directly served from the cache without fetching from the origin server because it does not change without manual intervention.Cache
static routeA fixed configuration to route traffic through Anycast tunnels from Cloudflare global network to the customer’s locations.Magic Transit, Magic WAN
Subject Alternative Names (SANs)The SAN field of an SSL certificate specifies additional hostnames (sites, IP addresses, common names, subdomains, apex domains, etc.) protected by a single SSL Certificate.SSL/TLS
subnetAlso known as subnetwork. It refers to a network that is part of another network.Magic Transit, Magic WAN
subrequestA subrequest is any request that a Worker makes to either Internet resources using the Fetch API or requests to other Cloudflare services like R2, KV, or D1.Workers
SYN (Synchronize)The initial step in establishing a TCP connection, where a device requests a connection with another by sending a SYN packet.Spectrum
SYN-ACK (Synchronize-Acknowledge)The second step in the TCP three-way handshake, where the server responds to a SYN request with a SYN-ACK packet.Spectrum
synthetic testA synthetic test is an artificial simulation of user interactions and system behaviors designed to evaluate and measure the performance, responsiveness, and functionality of a website or application under controlled conditions.Speed
Tail WorkerA Tail Worker receives information about the execution of other Workers (known as producer Workers), such as HTTP statuses, data passed to console.log() or uncaught exceptions.Workers
target endpointThe target endpoint is the ultimate destination that a request is sent to by API Shield’s routing feature.API Shield
TCP (Transmission Control Protocol)A connection-oriented protocol in the transport layer of the Internet Protocol Suite, providing reliable and ordered delivery of data between devices.Spectrum
TCP Fast Open (TFO)TCP Fast Open (TFO) is a protocol extension that can significantly improve the speed of establishing TCP connections by allowing data to be sent in the initial SYN packet, rather than requiring a separate handshake before data transmission begins.Fundamentals
TCP Keep-AliveA TCP keep-alive is used to maintain a connection between two endpoints by sending packets to check if the connection is still active. This helps prevent idle connections from being prematurely closed. If a response is not received after a defined period, the connection is terminated.Fundamentals
TCP RST (reset)A TCP Reset (RST) packet is used by a TCP sender to close a connection.Fundamentals
TCP three-way handshakeTCP uses a three-way handshake to establish a reliable connection (SYN, SYN-ACK, ACK) over an IP based connection. SYN is short for synchronize, and ACK is short for acknowledgement.Fundamentals
team domainA unique subdomain assigned to your Cloudflare account (for example, <your-team-name>, where users will find the apps you have secured behind Cloudflare Zero Trust.Cloudflare One
team name

The customizable portion of your team domain, allowing you to personalize your Cloudflare Zero Trust configuration. You can view your team name in Zero Trust under Settings > Custom Pages.

team domainteam name

To learn about the consequences of changing your team name, refer to the FAQ.

Cloudflare One
TerraformAn infrastructure as code software tool that allows you to deploy services from different providers using a standardized configuration syntax.Cloudflare One, Terraform
threat score

The threat score is a score from 0 (zero risk) to 100 (high risk) classifying the IP reputation of a visitor.

IP reputation is calculated based on Project Honeypot, external public IP information, as well as internal threat intelligence from WAF managed rules and DDoS.

time to first byte (TTFB)Time to first byte (TTFB) is the duration measured from the initiation of a web page request to the moment the first byte of data is received by the user’s browser from the web server, indicating the server’s initial response time.Speed
time to interactive (TTI)Time to interactive (TTI) is a web performance metric that measures the time it takes for a web page to become fully interactive and responsive to user input, indicating when users can effectively engage with and use the page.Speed
time-to-live (TTL)The duration for which a cached copy of a resource is considered valid before it needs to be refreshed or revalidated.Cache, Magic WAN
timestampA data field indicating the date and time when an event occurred, often used for sequencing and analysis.Logs
TLS (Transport Layer Security)TLS is a cryptographic protocol that ensures data security over a computer network, such as the Internet. It encrypts the data that is transmitted between a user’s computer and a web server.SSL/TLS
total bandwidth (total egress bandwidth, edge bandwidth)Total bandwidth is the amount of data transferred from Cloudflare to end users within a certain period of time. Total bandwidth equals the sum of all EdgeResponseBytes for a certain period of time.Cache
total blocking time (TBT)Total blocking time (TBT) is a web performance metric that measures the total amount of time between First Contentful Paint (FCP) and Time to Interactive (TTI) where the main thread was blocked for long enough to prevent input responsiveness.Speed
trafficTraffic is the data sent and received by visitors to a website. Cloudflare serves and protects this data as it passes through the Cloudflare network.Fundamentals
traffic managementThe process of controlling and optimizing the flow of network data to ensure efficient and reliable communication.Waiting Room
traffic steeringCloudflare evaluates your route’s health and steers traffic according to priorities defined by you and / or tunnel health.Magic Transit, Magic WAN
tunnelA secure pathway for network traffic to flow between a device and Cloudflare’s global network.Cloudflare One
tunnel health-checkA probe sent by Cloudflare to check for tunnel health. If a tunnel is not considered healthy, Cloudflare reroutes traffic to one that is considered healthy.Magic Transit, Magic WAN

A tutorial is a practical lesson that takes you from a clear starting to ending point.

The goal is to connect products to real-world scenarios to meet a user’s goal.

two-factor authentication (2FA)

Two-factor authentication (2FA) is a security process in which a user provides two different authentication factors to verify their identity. In addition to something you know, typically your password, 2FA adds an extra layer of security to user logins by requiring users to also present something they have, such as Yubikey or a one-time login code, or something you are, such as a fingerprint.

It adds an extra layer of security to user logins by requiring users to present two or more separate pieces of evidence (factors) that establish their identity.

Area 1, Fundamentals
UDP (User Datagram Protocol)UDP (User Datagram Protocol) is a connectionless transport layer protocol that provides fast and lightweight data transmission between devices on a network, prioritizing speed over reliability.Spectrum
uncached bandwidth (uncached egress bandwidth)Uncached bandwidth is the amount of bandwidth that is not cached and therefore is served from the origin. Uncached bandwidth is the sum of all EdgeResponseBytes where CacheCacheStatus does not equal hit, stale, updating, ignored, or revalidated.Cache
uncached requestsUncached requests are requests that are not cached and therefore are served from the origin server. Uncached requests are the sum of all requests where CacheCacheStatus does not equal to hit, stale, updating, or ignored.Cache
Unicast Reverse Path Forwarding (uRPF)A security feature that can prevent spoofing attacks.BYOIP
Universal SSL certificateBy default, Cloudflare issues — and renews — free, unshared, publicly trusted SSL certificates to all domains added to and activated on Cloudflare.SSL/TLS
URL normalizationThe process of modifying the URLs of incoming requests so that they conform to a consistent formatting standard.Rules
URL rewriteAn operation performed by a server that converts a source URL into a target URL.Rules
User risk scoreCloudflare Zero Trust user risk score ranks the likelihood of a user to introduce risk to your organization’s systems and data based on the detection of security risk behaviors. Risk scores add user and entity behavior analytics (UEBA) to the Zero Trust platform.Cloudflare One
User risk score levelCloudflare Zero Trust assigns a risk score of Low, Medium or High based on detections of users’ activities, posture, and settings. A user’s risk score is equal to the highest-level risk behavior they trigger.Cloudflare One
V8Chrome V8 is a JavaScript engine, which means that it executes JavaScript code.Workers
validation level

The level to which a certificate authority validates domain ownership before issuing an SSL/TLS certificate.

The different certificate validation levels are DV (Domain Validated), OV (Organization Validated), or EV (Extended Validation).

verified botBots that are transparent about who they are and what they do.Bots
versionA version is defined by the state of code as well as the state of configuration in a Worker’s wrangler.toml file.Workers
Virtual networkA software abstraction that allows you to logically segregate resources on a private network. Virtual networks are especially useful for exposing resources which have overlapping IP routes.Cloudflare One
Virtual Private Network (VPN)A tool that allows users to send and receive data across shared or public networks as if their devices were directly connected to the private network. For example, employees working from home can use a VPN to access files on the corporate network.Cloudflare One
virtual waiting roomA virtual waiting room is an online system or feature that manages and controls access to a website or service during periods of high traffic, preventing server overload by placing users in a queue until they can be accommodated, ensuring a more equitable and efficient user experience.Waiting Room
wall-clock timeWall-clock time is the total amount of time from the start to end of an invocation of a Worker.Workers
WANStands for Wide Area Network. It refers to a computer network that connects groups of computers over large distances. WANs are often used by businesses to connect their office networks. The objective is to make each of the local area networks (LANs) be remotely connected and accessible.Magic WAN
WARP clientAn application that connects corporate devices to Cloudflare for private network access, advanced web filtering, and other security functions.Cloudflare One
WARP ConnectorAn extension of the WARP client used to establish site-to-site, bidirectional, and mesh networking connectivity. WARP Connector software installs on a Linux server within a private network, which then becomes a gateway for other local networks that need to on-ramp traffic to Cloudflare.Cloudflare One
websiteA website is a collection of web pages and related content that is identified by a common domain name and published on at least one web server.Fundamentals
workerdworkerd is a JavaScript / Wasm server runtime based on the same code that powers Cloudflare Workers.Workers
WranglerWrangler is the Cloudflare Developer Platform command-line interface (CLI) that allows you to manage projects, such as Workers, created from the Cloudflare Developer Platform product offering.Workers
wrangler.tomlThe configuration file used to customize the development and deployment setup for a Worker or a Pages Function.Workers
Zero Trust SecurityZero Trust Security is an IT security model that requires strict identity verification for every person and device accessing resources on a network.Cloudflare One
zoneA zone is a portion of DNS namespace that is managed by a specific organization or administrator.Fundamentals