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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>curl - List of Features</title> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta content="text/html; charset=UTF-8" http-equiv="Content-Type"> <link rel="stylesheet" type="text/css" href="/curl.css"> <link rel="shortcut icon" href="/favicon.ico"> <link rel="icon" href="/logo/curl-symbol.svg" type="image/svg+xml"> <link rel="alternate" type="application/rss+xml" title="cURL Releases" href="https://github.com/curl/curl/releases.atom"> </head> <body> <div class="main"> <div class="menu"> <a href="/docs/" class="menuitem" title="Documentation Overview">Docs Overview</a> <div class="dropdown"> <a class="dropbtn" href="/docs/projdocs.html">Project</a> <div class="dropdown-content"> <a href="/docs/bugbounty.html">Bug Bounty</a> <a href="/docs/bugs.html">Bug Report</a> <a href="/docs/code-of-conduct.html">Code of conduct</a> <a 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href="/docs/thanks.html">Thanks</a> <a href="/docs/thename.html">The name</a> </div> </div> </div> <div class="contents"> <div class="where"><a href="/">curl</a> / <a href="/docs/">Docs</a> / <a href="/docs/projdocs.html">Project</a> / <b>Features</b></div> <div class="relatedbox"> <b>Related:</b> <br><a href="comparison-table.html">feature comparison table</a> </div>  <h1 id="features----what-curl-can-do">Features -- what curl can do</h1> <h2 id="curl-tool">curl tool</h2> <ul> <li>config file support</li> <li>multiple URLs in a single command line</li> <li>range "globbing" support: [0-13], {one,two,three}</li> <li>multiple file upload on a single command line</li> <li>redirect stderr</li> <li>parallel transfers</li> </ul> <h2 id="libcurl">libcurl</h2> <ul> <li>URL RFC 3986 syntax</li> <li>custom maximum download time</li> <li>custom lowest download speed acceptable</li> <li>custom output result after completion</li> <li>guesses protocol from hostname unless specified</li> <li>supports .netrc</li> <li>progress bar with time statistics while downloading</li> <li>standard proxy environment variables support</li> <li>have run on 101 operating systems and 28 CPU architectures</li> <li>selectable network interface for outgoing traffic</li> <li>IPv6 support on Unix and Windows</li> <li>happy eyeballs dual-stack IPv4 + IPv6 connects</li> <li>persistent connections</li> <li>SOCKS 4 + 5 support, with or without local name resolving</li> <li><em>pre-proxy</em> support, for <em>proxy chaining</em></li> <li>supports username and password in proxy environment variables</li> <li>operations through HTTP proxy "tunnel" (using CONNECT)</li> <li>replaceable memory functions (malloc, free, realloc, etc)</li> <li>asynchronous name resolving</li> <li>both a push and a pull style interface</li> <li>international domain names (IDN)</li> <li>transfer rate limiting</li> <li>stable API and ABI</li> <li>TCP keep alive</li> <li>TCP Fast Open</li> <li>DNS cache (that can be shared between transfers)</li> <li>non-blocking single-threaded parallel transfers</li> <li>Unix domain sockets to server or proxy</li> <li>DNS-over-HTTPS</li> <li>uses non-blocking name resolves</li> <li>selectable name resolver backend</li> </ul> <h2 id="url-api">URL API</h2> <ul> <li>parses RFC 3986 URLs</li> <li>generates URLs from individual components</li> <li>manages "redirects"</li> </ul> <h2 id="header-api">Header API</h2> <ul> <li>easy access to HTTP response headers, from all contexts</li> <li>named headers</li> <li>iterate over headers</li> </ul> <h2 id="tls">TLS</h2> <ul> <li>selectable TLS backend(s)</li> <li>TLS False Start</li> <li>TLS version control</li> <li>TLS session resumption</li> <li>key pinning</li> <li>mutual authentication</li> <li>Use dedicated CA cert bundle</li> <li>Use OS-provided CA store</li> <li>separate TLS options for HTTPS proxy</li> </ul> <h2 id="http">HTTP</h2> <ul> <li>HTTP/0.9 responses are optionally accepted</li> <li>HTTP/1.0</li> <li>HTTP/1.1</li> <li>HTTP/2, including multiplexing and server push</li> <li>GET</li> <li>PUT</li> <li>HEAD</li> <li>POST</li> <li>multipart formpost (RFC 1867-style)</li> <li>authentication: Basic, Digest, NTLM (9) and Negotiate (SPNEGO) to server and proxy</li> <li>resume transfers</li> <li>follow redirects</li> <li>maximum amount of redirects to follow</li> <li>custom HTTP request</li> <li>cookie get/send fully parsed</li> <li>reads/writes the Netscape cookie file format</li> <li>custom headers (replace/remove internally generated headers)</li> <li>custom user-agent string</li> <li>custom referrer string</li> <li>range</li> <li>proxy authentication</li> <li>time conditions</li> <li>via HTTP proxy, HTTPS proxy or SOCKS proxy</li> <li>HTTP/2 or HTTP/1.1 to HTTPS proxy</li> <li>retrieve file modification date</li> <li>Content-Encoding support for deflate, gzip, brotli and zstd</li> <li>"Transfer-Encoding: chunked" support in uploads</li> <li>HSTS</li> <li>alt-svc</li> <li>ETags</li> <li>HTTP/1.1 trailers, both sending and getting</li> </ul> <h2 id="https">HTTPS</h2> <ul> <li>HTTP/3</li> <li>using client certificates</li> <li>verify server certificate</li> <li>via HTTP proxy, HTTPS proxy or SOCKS proxy</li> <li>select desired encryption</li> <li>select usage of a specific TLS version</li> <li>ECH</li> </ul> <h2 id="ftp">FTP</h2> <ul> <li>download</li> <li>authentication</li> <li>Kerberos 5</li> <li>active/passive using PORT, EPRT, PASV or EPSV</li> <li>single file size information (compare to HTTP HEAD)</li> <li>'type=' URL support</li> <li>directory listing</li> <li>directory listing names-only</li> <li>upload</li> <li>upload append</li> <li>upload via http-proxy as HTTP PUT</li> <li>download resume</li> <li>upload resume</li> <li>custom ftp commands (before and/or after the transfer)</li> <li>simple "range" support</li> <li>via HTTP proxy, HTTPS proxy or SOCKS proxy</li> <li>all operations can be tunneled through proxy</li> <li>customizable to retrieve file modification date</li> <li>no directory depth limit</li> </ul> <h2 id="ftps">FTPS</h2> <ul> <li>implicit <code>ftps://</code> support that use SSL on both connections</li> <li>explicit "AUTH TLS" and "AUTH SSL" usage to "upgrade" plain <code>ftp://</code> connection to use SSL for both or one of the connections</li> </ul> <h2 id="ssh-both-scp-and-sftp">SSH (both SCP and SFTP)</h2> <ul> <li>selectable SSH backend</li> <li>known hosts support</li> <li>public key fingerprinting</li> <li>both password and public key auth</li> </ul> <h2 id="sftp">SFTP</h2> <ul> <li>both password and public key auth</li> <li>with custom commands sent before/after the transfer</li> <li>directory listing</li> </ul> <h2 id="tftp">TFTP</h2> <ul> <li>download</li> <li>upload</li> </ul> <h2 id="telnet">TELNET</h2> <ul> <li>connection negotiation</li> <li>custom telnet options</li> <li>stdin/stdout I/O</li> </ul> <h2 id="ldap">LDAP</h2> <ul> <li>full LDAP URL support</li> </ul> <h2 id="dict">DICT</h2> <ul> <li>extended DICT URL support</li> </ul> <h2 id="file">FILE</h2> <ul> <li>URL support</li> <li>upload</li> <li>resume</li> </ul> <h2 id="smb">SMB</h2> <ul> <li>SMBv1 over TCP and SSL</li> <li>download</li> <li>upload</li> <li>authentication with NTLMv1</li> </ul> <h2 id="smtp">SMTP</h2> <ul> <li>authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM, Kerberos 5 and External</li> <li>send emails</li> <li>mail from support</li> <li>mail size support</li> <li>mail auth support for trusted server-to-server relaying</li> <li>multiple recipients</li> <li>via http-proxy</li> </ul> <h2 id="smtps">SMTPS</h2> <ul> <li>implicit <code>smtps://</code> support</li> <li>explicit "STARTTLS" usage to "upgrade" plain <code>smtp://</code> connections to use SSL</li> <li>via http-proxy</li> </ul> <h2 id="pop3">POP3</h2> <ul> <li>authentication: Clear Text, APOP and SASL</li> <li>SASL based authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM, Kerberos 5 and External</li> <li>list emails</li> <li>retrieve emails</li> <li>enhanced command support for: CAPA, DELE, TOP, STAT, UIDL and NOOP via custom requests</li> <li>via http-proxy</li> </ul> <h2 id="pop3s">POP3S</h2> <ul> <li>implicit <code>pop3s://</code> support</li> <li>explicit <code>STLS</code> usage to "upgrade" plain <code>pop3://</code> connections to use SSL</li> <li>via http-proxy</li> </ul> <h2 id="imap">IMAP</h2> <ul> <li>authentication: Clear Text and SASL</li> <li>SASL based authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM, Kerberos 5 and External</li> <li>list the folders of a mailbox</li> <li>select a mailbox with support for verifying the <code>UIDVALIDITY</code></li> <li>fetch emails with support for specifying the UID and SECTION</li> <li>upload emails via the append command</li> <li>enhanced command support for: EXAMINE, CREATE, DELETE, RENAME, STATUS, STORE, COPY and UID via custom requests</li> <li>via http-proxy</li> </ul> <h2 id="imaps">IMAPS</h2> <ul> <li>implicit <code>imaps://</code> support</li> <li>explicit "STARTTLS" usage to "upgrade" plain <code>imap://</code> connections to use SSL</li> <li>via http-proxy</li> </ul> <h2 id="mqtt">MQTT</h2> <ul> <li>Subscribe to and publish topics using URL scheme <code>mqtt://broker/topic</code></li> </ul> </div> </div> </body> </html>