What's the difference between Kerno and Postman?
Postman is the industry standard for designing, testing, and collaborating on APIs. Kerno is the best tool for testing AI-generated backend code. It runs integration tests and API regression tests against your real infrastructure locally in Docker, catching breaking changes before code leaves your machine.
How do Kerno and Postman compare?
Scope
Local API testing and regression detection for AI-generated backend code, against real local infrastructure.
Full API lifecycle platform: design, test, document, monitor, collaborate, govern.
Test environment
Built-in. Derives your stack from existing config, orchestrates real dependencies locally in Docker, seeds data, executes tests, cleans up. Third-party services (e.g. Stripe) are automatically mocked.
Not built-in. You maintain test environments yourself. AI Engineer runs in a cloud-hosted sandbox but does not provision local infrastructure, seed data, or manage test lifecycle.
Test creation
Automatic. Indexes your codebase with SCIP, discovers endpoints, generates scenarios for functional workflows, API contract validation, error handling, auth, and edge cases.
Manual or AI-assisted. Build collections and write test scripts, or use AI to generate them. AI Engineer (beta) uses a Context Graph for more informed output.
Where validation happens
During development: runs API regression tests against baseline, flags breaking changes and unintended side effects with debug context. You approve intentional changes or reject and fix in the same session.
At PR time: AI Engineer triggers from PRs, Slack, or CLI, runs test suites in a sandbox, posts results back. During development: re-run collections manually or on a schedule.
Test maintenance
Flags regressions and unintended behavioral changes, waits for approval. Adds scenarios for new endpoints, retires removed ones. No manual upkeep.
Manual upkeep: edit collections when APIs change. AI Engineer (beta) can suggest updates. You review collections and decide when to update.
Native MCP server for API testing
Native MCP server for API testing. Your AI coding agent starts environments, captures baselines, runs regression tests, and fixes issues in one session.
MCP server with 100+ tools for platform access. AI Engineer (beta) triggers from PRs/Slack/CLI, runs suites in sandboxed environments.
What is Kerno good at?
Ltesting against your real stack
Kerno reads your build config and Docker Compose, orchestrates app and its dependencies locally in Docker, and runs integration tests against your real stack.
Kerno reads your build config and Docker Compose, orchestrates app and its dependencies locally in Docker, and runs integration tests against your real stack.
API regression testing in every coding session
Kerno runs API regression tests on every change against your real system and gives your agent the results in the same session.
Kerno runs API regression tests on every change against your real system and gives your agent the results in the same session.
Catch breaking changes before they ship
Kerno captures how your endpoints behave and flags breaking changes, regressions, and unintended side effects when code changes.
Kerno captures how your endpoints behave and flags breaking changes, regressions, and unintended side effects when code changes.
Automatic test lifecycle from your codebase
Kerno discovers endpoints, generates integration test scenarios and API contract validations, and proposes updates as your APIs evolve.
Kerno discovers endpoints, generates integration test scenarios and API contract validations, and proposes updates as your APIs evolve.
What is Postman good at?
API exploration and debugging
Postman is the most widely used tool for sending requests, inspecting responses, and debugging APIs during development.
Postman is the most widely used tool for sending requests, inspecting responses, and debugging APIs during development.
API design and documentation
Spec Hub, mock servers, SDK generation, and auto-generated documentation give teams a complete design-to-publish workflow.
Spec Hub, mock servers, SDK generation, and auto-generated documentation give teams a complete design-to-publish workflow.
Protocol coverage
Postman supports REST, GraphQL, gRPC, WebSocket, SOAP, and more. Kerno currently supports HTTP(S) only, with other protocols on the roadmap.
Postman supports REST, GraphQL, gRPC, WebSocket, SOAP, and more. Kerno currently supports HTTP(S) only, with other protocols on the roadmap.
API catalog and discoverability
Postman acts as a central registry where teams publish, discover, and version APIs across an organization.
Postman acts as a central registry where teams publish, discover, and version APIs across an organization.
Should I use Kerno, Postman, or both?
Use Postman if...
Your team needs a platform for API design, documentation, and collaboration. If you manually explore APIs, share collections, and generate SDKs.
Use Kerno if...
You use AI coding agents to write backend code and want automated API regression testing and integration testing against your real local infrastructure before code hits CI.
Use both if ...
You need a tool to manage how your team builds and shares APIs, and one to make sure your AI agent's code changes don't break them.
Trusted by AI-native engeneering teams to ship better software
Kerno was up and running in minutes with no manual work, and it made our API migration so much smoother. We could instantly validate that every change made by Cursor worked the way we expected, and now it's a core part of our how we build.
Misch Strotz
Co-Founder & CEO, LetzAI
Using Kerno with Claude Code has been a game changer. You get quick feedback with no manual effort, and it saves you a lot time and hassle debugging integration issues post-merge.
Jonathan Bernales
CTO, Germen
Kerno saves us a lot of manual work and helps us catch side effects and issues that would definitely break our projects' backends. Our engineering team loves it.
Santiago J. Valls
Co-Founder & CTO, Bewise
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Doesn't Postman already have AI-generated tests?
Do I need Kerno if I already use Postman?
Can I use Kerno and Postman together?
Does Kerno support GraphQL or gRPC like Postman?
How does Kerno handle intentional API changes vs accidental regressions?
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