Keploy, Joute's Review

The Essentials in 20 Seconds

• Captures your API's real network traffic and transforms it into automatic tests
• E2E and integration tests without writing a single line of test code manually
• Open source, integrated into CI/CD pipelines
• Price: free open source plan, cloud from $30/month

Verdict: Keploy's approach is genuinely different from other AI testing tools. Rather than generating tests from code, it generates them from real usage. For REST APIs, this is a powerful and pragmatic approach.

What is Keploy

Keploy is an open source automatic test generation tool. It intercepts your application's network traffic (HTTP requests, database calls) and automatically creates test cases with their associated mocks.

The result: regression tests based on real behaviors, not fictional scenarios invented by a developer.

Strengths

Tests based on real traffic

The generated tests match the behaviors your application actually had. No theoretical test cases: if the traffic generated this scenario, the test is relevant.

Automatic mocks

Keploy automatically mocks external dependencies (databases, third-party APIs) by recording their responses during capture. Your tests are reproducible without external infrastructure.

Open source and CI/CD-friendly

The core is open source (MIT). It integrates with GitHub Actions, Jenkins, CircleCI. If your CI pipeline already exists, Keploy plugs right in.

Limits

Works mainly on REST APIs

The traffic capture approach is optimized for REST APIs. For GraphQL applications, queue workers, or apps with heavy local state, coverage is more limited.

Cold start: needs real traffic

Keploy needs traffic to capture to generate tests. On a new project with no traffic, you start from zero. You either need to run it in staging or manually play through the scenarios once.

Pricing

• Open source: free, self-hostable
• Cloud: from $30/month

Alternatives

• Diffblue for AI-powered Java unit test generation
• Playwright for manually written E2E tests that are more flexible
• TestGPT for multi-language AI test generation

Verdict

Keploy is an innovative approach that teams maintaining REST APIs should try. The promise of zero manually written tests with real coverage is solid for this specific use case.

FAQ

Does Keploy support Go and Python?

Yes. Keploy supports Go, Python, Java, Node.js. The list of available SDKs is on keploy.io.

Are the generated tests editable?

Yes. Tests are generated in standard formats (YAML/JSON) that you can modify and version in your repo.

Do you need to modify application code to integrate Keploy?

Not for Go and some other languages. Keploy uses eBPF to capture traffic at the OS level without modifying code.

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