curl
curl: A mature, scriptable transfer tool for developers who prefer command-line workflows. Ranked #32 of 38 in API Clients by our editors (5.9/10); pricing: Free plan; best for scriptable command-line transfers.
At a glance
- Editor score5.9 / 10
- PricingFree plan
- Best forScriptable command-line transfers
- Free planYes
- Paid fromFree
- Founded1998
- Facts checked20 Sep 2026
Where it wins
- Free, open-source tool with broad protocol support
- Supports HTTP/1.1, HTTP/2, HTTP/3, and WebSockets
- Retries, timeouts, proxies, authentication, and parallel transfers
Where it doesn't
- Command-line interface rather than a graphical API client
- No stated team workspace or collaboration workflow
- Not positioned for automated API testing or documentation generation
Our verdict on curl
curl is an open-source command-line tool for getting and sending data with URL syntax, paired with the libcurl C API for embedding transfers in applications. It suits developers, automation workflows, and application teams that need scriptable network operations across Windows, macOS, Linux, Android, and iOS. Requests can use custom methods and headers, while transfers cover uploads, downloads, resumption, redirects, proxies, authentication, and rate controls. Its protocol range extends beyond HTTP and HTTPS to FTP, SFTP, SMTP, MQTT, and WebSocket connections through ws:// and wss://.
The main strength is breadth within a command-line and library model. curl supports HTTP/1.1, HTTP/2, and HTTP/3, along with HTTP, HTTPS, and SOCKS proxies. Authentication options include Basic, Digest, NTLM, Kerberos, and Bearer tokens. Parallel transfers, retries, timeouts, and rate limiting give scripts control over common transfer conditions, while libcurl lets developers embed URL transfers into C applications. This makes curl a strong fit when repeatable commands, protocol coverage, and application-level integration matter more than a visual request builder.
Its trade-off is focus. curl is not a graphical API client, and its stated capabilities center on requests, transfers, protocols, and scripting rather than team workspaces, automated API test runs, or documentation generation. Developers seeking a compact command-line utility or embeddable transfer library should find the model well aligned with their work. Teams that need collaborative API design, graphical exploration, GraphQL workflows, or built-in testing and documentation features should choose a more specialized API client instead.
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curl pricing
curl fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| GraphQL support | Not verified |
| gRPC support | Not verified |
| WebSocket support | Yes |
| Automated test runs | Not verified |
| API documentation | Not verified |
| Team workspaces | Not verified |
| Available platforms | Desktop |
| Deployment | Desktop, Mobile |
| Platforms | Windows, macOS, Linux, Android, iOS |
| Pricing | Free plan |
| Website | curl.se |
| Facts checked | 20 Sep 2026 |
Alternatives to curl
- PostmanA broad API workspace spanning requests, testing, mocking, specifications, and delivery workflows.9.4
- SoapUIA mature, testing-focused API client for REST, SOAP, GraphQL, and CI workflows.9.2
- ApidogA broad API workspace for teams that want design, testing, mocks, and CI/CD together.8.8
Also Ranked In
curl is ranked in 2 of our directories.
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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