Open-source Postman alternatives: 8 API testing tools
Metrics as of , from the GitHub or GitLab API of each repository. Refreshed monthly.
About Postman
Postman's site describes an API platform with an API client, a collection runner, mock servers and monitors. source: Postman home page
Postman is not listed on FreeQATools: the directory lists only tools released under an OSI-approved license (see the inclusion rules). No metrics are shown for it.
Order: Listed tools in the category that are not archived, by GitHub stars. Each line gives one fact from the tool's own documentation, with its source.
8 open-source tools
Bruno: Protocols: REST, GraphQL, SOAP, gRPC, WebSocket. source: Docs: Send Requests Overview
Hurl: Protocols: HTTP: REST, SOAP and GraphQL APIs, HTML content, XML and JSON based APIs. source: README
supertest: Protocols: HTTP; HTTP/2 through an http2 option. source: README
Karate: Protocols: REST over HTTP, GraphQL, SOAP, WebSocket. source: Docs: Why Karate?
REST Assured: Protocols: HTTP: any method, with explicit support for POST, GET, PUT, DELETE, OPTIONS, PATCH, HEAD. source: README
Schemathesis: Protocols: HTTP APIs described by OpenAPI or GraphQL schemas. source: README
RESTler: Protocols: REST APIs. source: README
Microcks: Protocols: HTTP (REST, SOAP, GraphQL, gRPC); Kafka, MQTT, AMQP, WebSocket, NATS, Google PubSub, Amazon SQS, Amazon SNS. source: Docs: Test Parameters
Repository metrics
| 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 |
1 Fetched from the GitHub or GitLab API on . Hover a value for its own date.