Apidog is the top-ranked API testing tool with load testing of the 5 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: Karate at $8.33/user/month billed annually.
These API testing tools can also send high volumes of requests to measure response times and error rates under load, so you can run functional and performance tests from one tool.
Included if: The vendor documents load or performance testing of APIs. We apply this rule to the same data as the full API testing tools ranking, so positions follow the overall score.
| 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 |
| Apache JMeter | 8.8/10 | Yes | See vendor | Yes | Yes | Yes | Not confirmed | Yes |
| ReadyAPI | 8.1/10 | No | $549.92/user/mo | Yes | Yes | Yes | Yes | Yes |
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 Java application for load and functional testing of web apps, APIs and other protocols.
SmartBear's commercial API testing suite covering functional, security, performance testing and service virtualization.
How much do API testing tools with load testing cost? Of the 5 API testing tools with load testing we ranked, 4 publish a paid starting price on annual billing. The lowest is $8.33/user/mo (Karate), 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 with load testing have a free plan? 4 of the 5 we ranked have a free plan: Apidog (9.8/10), Karate (9.8/10), Postman (9.8/10), Apache JMeter (8.8/10).
Which features set API testing tools with load testing apart? API mocking: 4 of 5 (Apidog, Karate, Postman and more). Every tool we ranked confirms REST API testing, GraphQL testing, load testing, CI/CD integration, so these do not separate them.
Apidog ranks first (9.8/10) among the 5 API testing tools that meet this rule: the vendor documents load or performance testing of APIs. Karate is second (9.8/10).
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.