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Upload a certificate bundle with an RSA and ECDSA certificate per custom hostname

Feb 14, 2025, 11:00 AM

SSL/TLS

Cloudflare has supported both RSA and ECDSA certificates across our platform for a number of years. Both certificates offer the same security, but ECDSA is more performant due to a smaller key size. However, RSA is more widely adopted and ensures compatibility with legacy clients. Instead of choosing between them, you may want both – that way, ECDSA is used when clients support it, but RSA is available if not.

Now, you can upload both an RSA and ECDSA certificate on a custom hostname via the API.

curl -X POST https://api.cloudflare.com/client/v4/zones/$ZONE_ID/custom_hostnames \
    -H 'Content-Type: application/json' \
    -H "X-Auth-Email: $CLOUDFLARE_EMAIL" \
    -H "X-Auth-Key: $CLOUDFLARE_API_KEY" \
    -d '{
    "hostname": "hostname",
    "ssl": {
        "custom_cert_bundle": [
            {
                "custom_certificate": "RSA Cert",
                "custom_key": "RSA Key"
            },
            {
                "custom_certificate": "ECDSA Cert",
                "custom_key": "ECDSA Key"
            }
        ],
        "bundle_method": "force",
        "wildcard": false,
        "settings": {
            "min_tls_version": "1.0"
        }
    }
}’

You can also:

• Upload an RSA or ECDSA certificate to a custom hostname with an existing ECDSA or RSA certificate, respectively.

• Replace the RSA or ECDSA certificate with a certificate of its same type.

• Delete the RSA or ECDSA certificate (if the custom hostname has both an RSA and ECDSA uploaded).

This feature is available for Business and Enterprise customers who have purchased custom certificates.