ETag Generator & Conditional Request Tester

Generate strong or weak ETags from text or uploaded files, assemble realistic cache validation headers, and simulate how an origin server should respond to If-None-Match and If-Match.

Strong + weak ETags Text or file input 304 / 412 / 428 simulation Runs locally in browser

Generate validator

Paste text, upload a file, or use a quick example. The browser hashes your data locally with Web Crypto.

Source

Hash algorithm

ETag mode

Resource body / fingerprint input

Resource path

Last-Modified

ValidatorStrong

AlgorithmSHA-256

Fingerprint length0 chars

Source size0 B

Generated output

ETag

Response headers

Example curl

Conditional request simulator

Cache validation Optimistic locking Wildcard support

Scenario

HTTP method

Server state

Require preconditionSimulate APIs that reject unsafe writes without If-Match or similar protection.

Allow weak cache comparisonUse weak comparison semantics for If-None-Match revalidation.

If-None-Match

If-Match

Generate an ETag, then simulate a request. The result panel will explain which precondition matched and why.

Decision summary

No simulation yet.

Request / response preview

No HTTP exchange generated yet.

Validator notes

Strong ETags require byte-for-byte equivalence. Weak ETags say the representation is semantically equivalent for caching, not necessarily identical.