Systems | Development | Analytics | API | Testing

Bruno is an open source, offline-first API client that stores your API collections as plain text files inside your Git repo. It gives you a fast GUI for building and sending REST, GraphQL, gRPC, and WebSocket requests, plus a scripting layer for writing tests against the responses. This guide covers Bruno API testing from install to CI, so by the end you can build a request, assert on its response, and run the whole suite from the command line.

Service virtualization replaces real external dependencies (APIs, databases, queues, or third-party services) with controlled simulations that respond like the real thing. Tests run against these virtual services whether the real dependency is unavailable, expensive to call, or still being built. Keploy implements this by capturing real dependency interactions from live traffic and replaying them automatically in CI.

Detecting API performance issues before they impact users is the difference between APIs that scale reliably and those that quietly erode user trust. When users encounter lag, failed requests, or timeouts, the consequences are immediate: lost transactions, customer frustration, and brand damage. Teams that build scalable APIs recognize that performance is not just a technical metric – it’s fundamental to business health and reputation.

Kong is named **a Leader** in *The Forrester Wave: API Management Software, Q3 2026*. APIs used to be about connecting systems to each other. Now they're also how AI agents connect to everything: tools, data, other agents. That shift changes what good API management looks like, and it's where we at Kong have shifted our focus. Forrester's take on where we land.

AI has changed how fast testing teams can move, yet sorting through duplicate test cases still trips teams up. Ask the SmartBear Zephyr Agent for Rovo to generate test cases for a requirement, and coverage that used to take an afternoon comes back in a single conversation. That speed is a genuine win for teams building faster than ever, but as AI generates more test coverage, how do you make sure all of it stays worth keeping?

Drift detection stays narrow on purpose. It checks contract conformance – structure, status codes, schema – and deliberately leaves workflows and business logic to functional and end-to-end tests. That’s what makes it a fast add to our pipeline to prevent API drift. That narrow scope keeps it cheap to run. Fast execution, low flakiness, low maintenance cost – the kind of checks that make you more confident shipping. Catching drift early is the whole point.

Handwritten mocks are cheap one at a time. This series built enough of them to show how quickly that stops being true. Nine posts took one package notifier from a function returning "delayed" to a captured response from a real carrier. Along the way, we hand-authored canned successes, failure cases, a spy, a stateful fake, an HTTP server, response fixtures, and contract-drift tests in four languages.

DreamFactory 7.7.0 is now the recommended stable release. It's a substantial one: AI agents become governed, human-owned API consumers; a new open-source API Builder lets you author custom REST endpoints without writing scripts; versioned Schema Contracts catch database drift before it reaches your consumers; and the platform baseline moves to Laravel 13.25 and PHP 8.3.

The notifier has returned a message throughout this series, which made testing almost suspiciously easy. Assert on the return value and you are done. Real notifiers do more than build strings: they send them. Once a message goes to an email provider or SMS gateway, the function may return nothing useful. When that change lands, every existing test loses the value it asserted on. This is part 4 of a ten-part series. The code is in Java, Node.js, Go and Python.