Open-source API testing tools: 11 compared
Tools for testing HTTP, GraphQL and gRPC APIs, including clients and assertion libraries.
11 tools are listed here, 3 of them with this as a secondary category. Each one is open source under an OSI-approved license and meets the inclusion rules. The table is sorted by GitHub stars, descending, on the fetch date. Select a column heading to sort by another column.
Metrics as of , from the GitHub or GitLab API of each repository. Refreshed monthly.
| Bruno | 47,1111 | 2026-08-201v4.1.0 | 2026-09-221 | MIT | JavaScript | active |
|---|---|---|---|---|---|---|
| Hurl | 19,2101 | 2026-04-2918.0.1 | 2026-09-211 | Apache-2.0 | Rust | active |
| supertest | 14,4041 | 2026-09-221v7.3.0 | 2026-09-221 | MIT | JavaScript | active |
| Karate | 8,9651 | 2026-08-141v2.1.2 | 2026-09-191 | MIT | Java | active |
| REST Assured | 7,1411 | 2026-07-101rest-assured-6.0.1 | 2026-07-221 | Apache-2.0 | Java | active |
| Schemathesis | 3,6181 | 2026-09-191v4.27.5 | 2026-09-221 | MIT | Python | active |
| RESTler | 2,9461 | 2025-01-301v9.3.1 | 2026-02-131 | MIT | Python | slow |
| Microcks | 2,0461 | 2026-08-0511.15.0 | 2026-09-221 | Apache-2.0 | Java | active |
| Step CI | 1,8671 | 2024-06-1012.8.2 | 2024-08-031 | MPL-2.0 | TypeScript | inactive |
| Tavern | 1,1611 | 2026-03-281v3.3.0 | 2026-09-111 | MIT | Python | active |
| EvoMaster | 7821 | 2026-09-151v6.2.0 | 2026-09-221 | LGPL-3.0 | Kotlin | active |
1 Fetched from the GitHub or GitLab API on . Hover a value for its own date.
Comparisons in this category
Guide
Open-source api testing tools: how the list is sorted and what each covers