{"product_id":"prove-openai-retry-cache-hits-in-n8n-with-metrecept-jwks","title":"Prove OpenAI Retry Cache HITs in n8n with Metrecept JWKS","description":"\u003ch3\u003eProve OpenAI Retry Cache HITs in n8n (with Metrecept JWKS verification)\u003c\/h3\u003e\n\u003cp\u003eThis n8n workflow sends the \u003cem\u003eexact same\u003c\/em\u003e OpenAI-style chat completion request to Metrecept twice—first to demonstrate a cache MISS, then (optionally) to produce and prove a cache HIT—verifying the returned receipt signature using \u003cstrong\u003eMetrecept’s public JWKS\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAccepts input via manual run or webhook:\u003c\/strong\u003e a POST request containing \u003ccode\u003eprompt\u003c\/code\u003e or \u003ccode\u003emessages\u003c\/code\u003e (optionally \u003ccode\u003emodel\u003c\/code\u003e and \u003ccode\u003eprove_retry\u003c\/code\u003e).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNormalizes and freezes the payload:\u003c\/strong\u003e converts your input into an OpenAI Chat Completions request body, freezes it as a JSON string, and returns HTTP 400 if no \u003ccode\u003emessages\u003c\/code\u003e are provided.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSends the request to Metrecept:\u003c\/strong\u003e posts the frozen payload to \u003ccode\u003e\/v1\/chat\/completions\u003c\/code\u003e and captures cache\/billing headers. Returns HTTP 402 on budget errors and HTTP 502 for other upstream failures.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGenerates a retry HIT (optional):\u003c\/strong\u003e when \u003ccode\u003eprove_retry\u003c\/code\u003e is enabled and the first response is a cache MISS, the workflow sends the identical payload again to trigger a cache HIT.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVerifies the receipt signature (JWKS):\u003c\/strong\u003e if a receipt JWS header is present, it fetches Metrecept’s public key directory (JWKS) and verifies the \u003cstrong\u003eEd25519\u003c\/strong\u003e signature. If missing, it reports verification as unavailable.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReturns a consolidated proof object:\u003c\/strong\u003e includes mode, cache status, billed amounts, receipt verification result, and current usage from Metrecept \u003ccode\u003e\/v1\/usage\u003c\/code\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eAudit that “retry” behavior in your OpenAI-style integrations actually yields cache HITs.\u003c\/li\u003e\n  \u003cli\u003eValidate Metrecept receipt integrity for compliance or internal reliability testing.\u003c\/li\u003e\n  \u003cli\u003eEstimate billed impact by comparing MISS vs HIT scenarios with returned usage data.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003en8n nodes:\u003c\/strong\u003e \u003ccode\u003ewebhook\u003c\/code\u003e, \u003ccode\u003eif\u003c\/code\u003e, \u003ccode\u003eset\u003c\/code\u003e, \u003ccode\u003ecode\u003c\/code\u003e, \u003ccode\u003eswitch\u003c\/code\u003e, plus sticky notes for clarity.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMetrecept integration:\u003c\/strong\u003e HTTP calls to \u003ccode\u003e\/v1\/chat\/completions\u003c\/code\u003e and \u003ccode\u003e\/v1\/usage\u003c\/code\u003e, plus public JWKS fetch for receipt verification.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAuth setup:\u003c\/strong\u003e an n8n HTTP Header Auth credential using \u003ccode\u003eAuthorization: Bearer \u0026lt;your_intermediate_key\u0026gt;\u003c\/code\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":46029430292659,"sku":"N8N-19595","price":52.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/YE58pUpKfgCnfS5oII7_X_1JNGZvJe.png?v=1789463551","url":"https:\/\/buyflowscripts.com\/products\/prove-openai-retry-cache-hits-in-n8n-with-metrecept-jwks","provider":"N8N Commerce","version":"1.0","type":"link"}