Apidog, Karate, Postman, Bruno, Insomnia, Hoppscotch, Apache JMeter, Katalon Studio, REST Assured have free plans. The highest-ranked is Apidog (9.8/10): Up to 4 users; API client, mocking, unlimited test/collection runs, local performance tests, Apidog CLI, 5 team projects
API testing tools send requests to an API and check the responses: status codes, response bodies, headers, timing and contract compliance. They range from desktop and web clients used for exploring and debugging APIs, to code-based frameworks that run in CI/CD, to platforms that add mocking, load testing and team collaboration.
| Tool | Score | Free plan | Paid from (annual) | REST API testing | GraphQL testing | Load testing | API mocking | CI/CD integration |
|---|---|---|---|---|---|---|---|---|
| Apidog | 9.8/10 | Yes | $9/user/mo | Yes | Yes | Yes | Yes | Yes |
| Karate | 9.8/10 | Yes | $8.33/user/mo | Yes | Yes | Yes | Yes | Yes |
| Postman | 9.8/10 | Yes | $9/user/mo | Yes | Yes | Yes | Yes | Yes |
| Bruno | 9.4/10 | Yes | $6/user/mo | Yes | Yes | Not confirmed | Yes | Yes |
| Insomnia | 9.4/10 | Yes | $10/user/mo | Yes | Yes | Not confirmed | Yes | Yes |
| Hoppscotch | 8.9/10 | Yes | $6/user/mo | Yes | Yes | Not confirmed | Yes | Not confirmed |
| Apache JMeter | 8.8/10 | Yes | See vendor | Yes | Yes | Yes | Not confirmed | Yes |
| Katalon Studio | 8.7/10 | Yes | $150/user/mo | Yes | Yes | Not confirmed | Not confirmed | Yes |
| REST Assured | 7.5/10 | Yes | See vendor | Yes | Not confirmed | Not confirmed | Not confirmed | Not confirmed |
| Tool | What the free plan includes | First paid plan |
|---|---|---|
| Apidog | Up to 4 users; API client, mocking, unlimited test/collection runs, local performance tests, Apidog CLI, 5 team projects | $9/user/mo (annual) |
| Karate | Open-source Karate framework (MIT) plus free tier of Xplorer desktop client | $8.33/user/mo (annual) |
| Postman | 1 user, API client, specs and mock servers, Collection Runner and local performance testing, 1,000 API monitoring requests/month, 100 AI credits | $9/user/mo (annual) |
| Bruno | Open Source edition: 2 workspaces, public Git providers, 5 OpenAPI syncs/month, unlimited collection runner, community support | $6/user/mo (annual) |
| Insomnia | Essentials: Git Sync projects for up to 3 users, unlimited cloud/local projects, unlimited collection runs, Inso CLI, 1,000 mock requests/month; also a local-only Scratch Pad | $10/user/mo (annual) |
| Hoppscotch | Free forever: REST, GraphQL and realtime API testing, personal workspace, collections, environments, scripts and tests, collection runner | $6/user/mo (annual) |
| Apache JMeter | Open source (Apache License 2.0), free download | See vendor |
| Katalon Studio | Local authoring, record and playback, local execution; up to 40 static test suites; no CI/CD or parallel execution | $150/user/mo (annual) |
| REST Assured | Open source library (Apache 2.0) | See vendor |
All-in-one API platform for design, debugging, mocking, testing and documentation.
Open-source framework for API, UI and performance testing, with paid IDE plugins and an enterprise edition.
API platform for building, testing, mocking and monitoring APIs.
Open-source, Git-native API client that stores collections as plain files.
Open-source API client from Kong for debugging, testing and mocking APIs.
Open-source API development platform for REST, GraphQL and realtime APIs, in the browser or self-hosted.
Open-source Java application for load and functional testing of web apps, APIs and other protocols.
Test automation tool for web, API, mobile and desktop testing.
Open-source Java library for testing REST services.
Yes. Up to 4 users; API client, mocking, unlimited test/collection runs, local performance tests, Apidog CLI, 5 team projects Paid plans start at $9/user/mo billed annually.
Yes. Open-source Karate framework (MIT) plus free tier of Xplorer desktop client Paid plans start at $8.33/user/mo billed annually.
Yes. 1 user, API client, specs and mock servers, Collection Runner and local performance testing, 1,000 API monitoring requests/month, 100 AI credits Paid plans start at $9/user/mo billed annually.
Yes. Open Source edition: 2 workspaces, public Git providers, 5 OpenAPI syncs/month, unlimited collection runner, community support Paid plans start at $6/user/mo billed annually.
Yes. Essentials: Git Sync projects for up to 3 users, unlimited cloud/local projects, unlimited collection runs, Inso CLI, 1,000 mock requests/month; also a local-only Scratch Pad Paid plans start at $10/user/mo billed annually.
Yes. Free forever: REST, GraphQL and realtime API testing, personal workspace, collections, environments, scripts and tests, collection runner Paid plans start at $6/user/mo billed annually.
Yes. Open source (Apache License 2.0), free download Paid plans start at see vendor.
Yes. Local authoring, record and playback, local execution; up to 40 static test suites; no CI/CD or parallel execution Paid plans start at $150/user/mo billed annually.
Yes. Open source library (Apache 2.0) Paid plans start at see vendor.
Scores come from published, repeatable data (features, free plan, entry price, pricing transparency). No vendor can pay to change a score. Read the methodology · Disclosure.