https://nalar.dev/tags/apis/ Recent content in APIs on Nalar Hugo en-us Wed, 02 Sep 2026 00:00:00 +0700 https://nalar.dev/http-content-negotiation-and-correct-vary-headers/ Wed, 02 Sep 2026 00:00:00 +0700 https://nalar.dev/http-content-negotiation-and-correct-vary-headers/ <p>One URL can sometimes represent the same resource in several formats. An API might return JSON or CSV, while a documentation endpoint might return HTML or plain text.</p> <p>HTTP content negotiation lets a client express which representation it can accept. The server chooses a response and tells caches which request headers influenced that choice.</p> <p>The second part is easy to miss: if the response changes based on a request header, shared caches need the correct <code>Vary</code> metadata.</p> https://nalar.dev/contract-tests-for-service-boundaries/ Tue, 01 Sep 2026 00:00:00 +0700 https://nalar.dev/contract-tests-for-service-boundaries/ <p>Distributed systems fail in an awkward place: each service can pass its own tests while the interaction between two services is incompatible.</p> <p>A provider may rename a JSON field, tighten validation, change an enum, or stop returning a value that a consumer quietly depends on. Contract tests make those cross-service assumptions executable.</p> <h2 id="what-a-contract-is">What a contract is</h2> <p>A contract describes an observable interaction between a consumer and a provider.</p> <p>For an HTTP API, it might specify:</p>