Apidog is the top-ranked API testing tool of the 11 we ranked (9.8/10, free plan), best for teams that want API design, mocks, tests and docs in one tool at a low per-user price. Karate is the runner-up (9.8/10).
Cheapest paid entry: Bruno at $6/user/month billed annually.
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 |
| ReadyAPI | 8.1/10 | No | $549.92/user/mo | Yes | Yes | Yes | Yes | Yes |
| iceDQ | 7.8/10 | No | See vendor | Yes | Yes | Not confirmed | Not confirmed | Yes |
| REST Assured | 7.5/10 | Yes | See vendor | Yes | Not confirmed | Not confirmed | Not confirmed | Not confirmed |
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.
SmartBear's commercial API testing suite covering functional, security, performance testing and service virtualization.
Data testing, reconciliation and monitoring platform from Torana Inc. that checks data across databases, files, APIs and BI reports.
Open-source Java library for testing REST services.
How much do API testing tools cost? Of the 11 API testing tools we ranked, 8 publish a paid starting price on annual billing. The lowest is $6/user/mo (Bruno), the median is $9/user/mo and the highest entry price is $549.92/user/mo (ReadyAPI). Prices checked November 2026.
How many API testing tools publish their prices? 10 of the 11 we ranked publish a price or a free plan; 1 is quote-only: iceDQ.
How many API testing tools have a free plan? 9 of the 11 we ranked have a free plan: Apidog (9.8/10), Karate (9.8/10), Postman (9.8/10), Bruno (9.4/10), Insomnia (9.4/10), Hoppscotch (8.9/10), Apache JMeter (8.8/10), Katalon Studio (8.7/10), REST Assured (7.5/10).
Which features set API testing tools apart? GraphQL testing: 10 of 11 (Apidog, Karate, Postman and more). CI/CD integration: 9 of 11 (Apidog, Karate, Postman and more). API mocking: 7 of 11 (Apidog, Karate, Postman and more). Every tool we ranked confirms REST API testing, so it does not separate them.
Apidog ranks first on our data score (9.8/10). It is best for teams that want API design, mocks, tests and docs in one tool at a low per-user price. Karate is second (9.8/10).
Bruno has the lowest paid entry price in this list at $6 per user/month billed annually. Free plans are available from Apidog, Karate, Postman, Bruno, Insomnia, Hoppscotch, Apache JMeter, Katalon Studio, REST Assured.
Apidog, Karate, Postman, Bruno, Insomnia, Hoppscotch, Apache JMeter, Katalon Studio, REST Assured offer a free plan. ReadyAPI, iceDQ do not.
API testing checks an application programming interface directly, without a user interface, by sending requests and verifying the responses (status code, data, headers, response time) against expected results.
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.