curl
curl · founded 1998
What it is
curl is a free command-line tool and library for transferring data using URLs. It is used in commands and scripts, while libcurl is embedded in a wide range of devices and software. Supported protocols include HTTP, HTTPS, FTP, SFTP, SMTP, IMAP, MQTT, and WebSocket. For HTTP, listed capabilities include GET, POST, and PUT, plus cookies, custom headers, redirects, HTTP/2, HTTP/3, HSTS, and Alt-Svc. Its TLS features include versions 1.0 through 1.3, mutual authentication, OCSP stapling, ECH, key pinning, and session resumption. Transfer controls include limits, stall detection, retries, timeouts, and parallel or serial transfers. libcurl provides a stable API and ABI, persistent connections, proxy chaining, IPv6, DNS-over-HTTPS, and transfer rate limiting. The project mostly provides source packages; external people and organizations provide other packages. Documentation, mailing lists, chat, videos, and a free online book are available. Commercial support through wolfSSL includes customization, ports, feature work, patch maintenance, bug fixing, security scanning, and options up to 24/7 support.
For and against
For
- Free and open source
- Supports HTTP, HTTPS, FTP, SFTP, MQTT, and WebSocket
- Includes retries, timeouts, and transfer rate limits
- libcurl offers a stable API and ABI
Against
- The project mostly provides source packages
- Other packages come from external people and organizations
The verdict
curl pairs command-line transfers with a library for embedding in applications and devices. Its documentation, community channels, and optional commercial support provide different ways to get help.
Who it suits
curl suits people who transfer data from command lines or scripts, and developers embedding libcurl in software or devices. Its broad protocol and transfer controls also serve varied network-transfer needs.
Plans and prices
curl
Free and open source software; transfers data using URLs
Read 11 Oct 2026 · curl.se
On the record
- Commercial support
- Commercial support through wolfSSL includes customization, ports, feature development, patch maintenance, bug fixing, security scanning, and options up to 24/7 support.curl.se · read 11 Oct 2026
- Community support
- The project provides documentation, mailing lists, IRC or chat, videos, and a free online book called Everything curl.curl.se · read 11 Oct 2026
- Distribution
- The curl project mostly provides source packages, while other packages are provided by external people and organizations.curl.se · read 11 Oct 2026
- HTTP features
- Its HTTP capabilities include GET, POST, PUT, cookies, custom headers, redirects, HTTP/2, HTTP/3, HSTS, and Alt-Svc.curl.se · read 11 Oct 2026
- Latest release
- The page lists curl 8.22.0 as the latest stable version, released on 2026-09-02.curl.se · read 11 Oct 2026
- Library capabilities
- libcurl provides a stable API and ABI and supports features such as persistent connections, proxy chaining, IPv6, DNS-over-HTTPS, and transfer rate limiting.curl.se · read 11 Oct 2026
- Protocols
- curl supports protocols including HTTP, HTTPS, FTP, SFTP, SMTP, IMAP, MQTT, WebSocket, and many others.curl.se · read 11 Oct 2026
- Purpose
- curl is a command line tool and library for transferring data with URLs.curl.se · read 11 Oct 2026
- Security features
- Listed TLS features include versions 1.0–1.3, mutual authentication, OCSP stapling, ECH, key pinning, and session resumption.curl.se · read 11 Oct 2026
- Security reporting
- The project asks people who find or suspect a security problem in curl or libcurl to file a detailed report and links to a table of vulnerable versions.curl.se · read 11 Oct 2026
- Transfer controls
- The project lists transfer and request rate limits, stall detection, retries, timeouts, and parallel or serial transfers.curl.se · read 11 Oct 2026
- Use cases
- The project says curl is used in command lines and scripts, while libcurl is embedded in a wide range of devices and software applications.curl.se · read 11 Oct 2026
- WebSocket support
- Yescurl.se · read 20 Sep 2026
