Snippets examples

Refer to the following examples to get started creating your snippet code.

Refer to How Snippets work and Create a snippet in the dashboard for overall guidance.

A/B testing with same-URL direct access

Set up an A/B test by controlling what response is served based on cookies.

Append dates to cookies to use with A/B testing

Dynamically set a cookie expiration and test group.

Auth with headers

Allow or deny a request based on a known pre-shared key in a header. This is not meant to replace the WebCrypto API.

Send Bot Management information to origin

Send Bots information to your origin. Refer to Bot Management variables for a full list of available fields.

Send suspect bots to a honeypot

Use the bot score field to send bots to a honeypot.

Bulk redirect based on a map object

Redirect requests to certain URLs based on a mapped object to the request's URL.

Country code redirect

Redirect a response based on the country code in the header of a visitor.

Custom cache

Store, retrieve, and remove assets from cache programmatically. Use this template to optimize performance and implement custom caching strategies.

Debugging logs

Send debugging information in an errored response to a logging service.

Define CORS headers

Adjust Cross-Origin Resource Sharing (CORS) headers and handle preflight requests.

Follow redirects from the origin

Modify the fetch request to follow redirects from the origin, ensuring the client receives the final response.

Add HEX timestamp to a request header

Add a custom header to requests sent to the origin server with the current timestamp in hexadecimal format for debugging, tracking, or custom routing purposes.

Validate JSON web tokens (JWT)

Extract a JWT from the Authorization header, verify its HMAC-SHA256 signature using the WebCrypto API, and validate its claims.

Maintenance page

Serve a custom maintenance page instead of fetching content from the origin server or cache. Ideal for downtime notifications, planned maintenance, or emergency messages.

Override a Set-Cookie header with a certain value

Get a specific Set-Cookie header and update it with a certain value.

Redirect 403 Forbidden to a different page

If origin responded with 403 Forbidden error code, redirect to different page.

Redirect from one domain to another

Redirect all requests from one domain to another domain.

Remove fields from API response

If origin responds with JSON, parse the response and delete fields to return a modified response.

Remove query strings before sending request to origin

Remove certain query strings from a request before passing to the origin.

Remove response headers

Remove from response all headers that start with a certain name.

Return information about the incoming request

Respond with information about the incoming request provided by Cloudflare’s global network.

Rewrite links on HTML pages

Dynamically rewrite links in HTML responses. This is useful for site migrations and branding updates.

Change origin and modify paths

Route requests to a different origin, prepend a directory to the URL path, and remove specific segments.

Set security headers

Set common security headers such as X-XSS-Protection, X-Frame-Options, and X-Content-Type-Options.

Send timestamp to origin as a custom header

Convert timestamp to hexadecimal format and send it as a custom header to the origin.

Route to a different origin based on origin response

If response to the original request is not 200 OK or a redirect, send to another origin.

Sign requests

Verify a signed request using the HMAC and SHA-256 algorithms or return a 403.

Slow down suspicious requests

Define a delay to be used when incoming requests match a rule you consider suspicious based on the bot score.