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If-None-Match Header

Makes the request conditional; execution occurs only if the client ETag does not match the server ETag.

Header TypeRequest Header
SpecificationStandard RFC compliant
Associated CodesHTTP 304,HTTP 412

What is the If-None-Match header?

The If-None-Match request header is used for conditional GET requests. The server will send the full resource only if the current ETag on the server does not match the client’s ETag.

API Usage & Best Practices

  • Enable HTTP/CDN Caching: Essential for optimizing mobile apps or web frontends querying configuration, catalogs, or large asset datasets.
  • Returns 304: If the ETags match, return 304 Not Modified with no body.

Examples

GET /v1/leads/lead_123 HTTP/1.1
If-None-Match: "w/3a84e27f01"

Associated HTTP Status Codes

HTTP 304 — Not Modified

Instructs the client that the cached version of the resource is still valid.

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HTTP 412 — Precondition Failed

One or more preconditions in the request headers evaluated to false.

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