curl / libcurl / API / Examples

libcurl - small example snippets

A collection of smaller stand-alone applications using the libcurl API in different ways to show how to use it for different Internet transfer scenarios.

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You can also see a list of all libcurl easy options and which example source codes that use them.

All examples are written in C, unless specifically mentioned.

Index of examples

10-at-a-time	Download many files in parallel, in the same thread.
address-scope	HTTP GET to an IPv6 address with specific scope
altsvc	HTTP with Alt-Svc support
anyauthput	HTTP PUT upload with authentication using "any" method. libcurl picks the one the server supports/wants.
cacertinmem	CA cert in memory with OpenSSL to get an HTTPS page.
certinfo	Extract lots of TLS certificate info.
chkspeed	Show transfer timing info after download completes.
connect-to	Use CURLOPT_CONNECT_TO to connect to "wrong" hostname
cookie_interface	Import and export cookies with COOKIELIST.
crawler	Web crawler based on curl and libxml2 to stress-test curl with hundreds of concurrent connections to various servers.
debug	Show how CURLOPT_DEBUGFUNCTION can be used.
default-scheme	Change default scheme when none is provided in the URL
ephiperfifo	multi socket API usage with epoll and timerfd
evhiperfifo	multi socket interface together with libev
externalsocket	Pass in a custom socket for libcurl to use.
fileupload	Upload to a file:// URL
ftp-wildcard	FTP wildcard pattern matching
ftpget	Get a single file from an FTP server.
ftpgetinfo	Checks a single file's size and mtime from an FTP server.
ftpgetresp	Similar to ftpget.c but also stores the received response-lines in a separate file using our own callback!
ftpsget	Get a single file from an FTPS server.
ftpupload	Performs an FTP upload and renames the file just after a successful transfer.
ftpuploadfrommem	FTP upload a file from memory
ftpuploadresume	Upload to FTP, resuming failed transfers. Active mode.
getinfo	Use getinfo to get content-type after completed transfer.
getinmemory	Shows how the write callback function can be used to download data into a chunk of memory instead of storing it in a file.
getredirect	Show how to extract Location: header and URL to redirect to.
getreferrer	Show how to extract referrer header.
ghiper	multi socket API usage together with glib2
headerapi	Extract headers post transfer with the header API
hiperfifo	multi socket API usage with libevent 2
href_extractor	Uses the "Streaming HTML parser" to extract the href pieces in a streaming manner from a downloaded HTML.
hsts-preload	Preload domains to HSTS
htmltidy	Download a document and use libtidy to parse the HTML.
htmltitle (C++)	Get a web page, extract the title with libxml.
http-options	Issue an HTTP 'OPTIONS *' request
http-post	simple HTTP POST using the easy interface
http2-download	Multiplexed HTTP/2 downloads over a single connection
http2-pushinmemory	HTTP/2 server push. Receive all data in memory.
http2-serverpush	HTTP/2 server push
http2-upload	Multiplexed HTTP/2 uploads over a single connection
http3	Very simple HTTP/3 GET
http3-present	Checks if HTTP/3 support is present in libcurl.
httpcustomheader	HTTP request with custom modified, removed and added headers
httpput	HTTP PUT with easy interface and read callback
httpput-postfields	HTTP PUT using CURLOPT_POSTFIELDS
https	Simple HTTPS GET
imap-append	Send email with IMAP
imap-authzid	Retrieve emails from a shared IMAP mailbox
imap-copy	Copy an email from one IMAP folder to another
imap-create	Create a new IMAP folder
imap-delete	Delete an IMAP folder
imap-examine	Obtain information about an IMAP folder
imap-fetch	Retrieve IMAP emails
imap-list	List the folders within an IMAP mailbox
imap-lsub	List the subscribed IMAP folders
imap-multi	Get IMAP email with the multi interface
imap-noop	Perform an IMAP noop
imap-search	Search for new IMAP emails
imap-ssl	IMAP with implicit SSL
imap-store	Modify the properties of an email over IMAP
imap-tls	IMAP using TLS
interface	Use CURLOPT_INTERFACE to bind the outgoing socket to an interface
ipv6	HTTPS GET using IPv6 only
keepalive	Use the TCP keep-alive options
localport	Use CURLOPT_LOCALPORT to control local port number
maxconnects	Set maximum number of persistent connections to 1.
multi-app	A basic application source code using the multi interface doing two transfers in parallel.
multi-debugcallback	multi interface and debug callback
multi-double	multi interface code doing two parallel HTTP transfers
multi-event	multi_socket API using libevent
multi-formadd	using the multi interface to do a multipart formpost without blocking
multi-legacy	A basic application source code using the multi interface doing two transfers in parallel without curl_multi_wait/poll.
multi-post	using the multi interface to do a multipart formpost without blocking
multi-single	using the multi interface to do a single download
multi-uv	multi_socket API using libuv
multithread	A multi-threaded program using pthreads to fetch several files at once
netrc	Use credentials from .netrc
parseurl	Basic URL API use.
persistent	reusing handles to do HTTP persistent connections
pop3-authzid	Retrieve emails from a shared POP3 mailbox
pop3-dele	Delete POP3 emails
pop3-list	List the contents of a POP3 mailbox
pop3-multi	Get POP3 email using the multi interface
pop3-noop	Perform a POP3 noop
pop3-retr	Retrieve POP3 email
pop3-ssl	Get POP3 email using implicit SSL
pop3-stat	Obtain POP3 message statistics
pop3-tls	POP3 using TLS
pop3-top	POP3 example showing how to retrieve only the headers of an email
pop3-uidl	List the contents of a POP3 mailbox by unique ID
post-callback	Issue an HTTP POST and provide the data through the read callback.
postinmemory	Make an HTTP POST with data from memory and receive response in memory.
postit2	HTTP Multipart formpost with file upload and two additional parts.
postit2-formadd	HTTP Multipart formpost with file upload and two additional parts.
progressfunc	Use the progress callbacks, old and/or new one depending on available libcurl version.
protofeats	Outputs all protocols and features supported
range	GET a range only of an HTTP resource
resolve	Use CURLOPT_RESOLVE to feed custom IP addresses for given hostname + port number combinations.
rtsp-options	Very simple RTSP request sending OPTIONS.
sendrecv	Demonstrate curl_easy_send() and curl_easy_recv() usage.
sepheaders	Simple HTTP GET that stores the headers in a separate file
sessioninfo	Uses the CURLINFO_TLS_SESSION data.
sftpget	Gets a file using an SFTP URL.
sftpuploadresume	Upload to SFTP, resuming a previously aborted transfer.
shared-connection-cache	Connection cache shared between easy handles with the share interface
simple	Very simple HTTP GET
simplepost	Very simple HTTP POST
simplessl	Shows HTTPS usage with client certs and optional ssl engine use.
smooth-gtk-thread	A multi threaded application that uses a progress bar to show status. It uses Gtk+ to make a smooth pulse.
smtp-authzid	Send email on behalf of another user with SMTP
smtp-expn	Expand an SMTP email mailing list
smtp-mail	Send email with SMTP
smtp-mime	Send SMTP mime emails
smtp-multi	Send SMTP email with the multi interface
smtp-ssl	Send SMTP email using implicit SSL
smtp-tls	Send SMTP email using implicit TLS
smtp-vrfy	Verify an SMTP email address
sslbackend	Shows HTTPS usage with client certs and optional ssl engine use.
synctime	Set your system time from a remote HTTP server's Date: header.
threaded-ssl	Show the required mutex callback setups for GnuTLS and OpenSSL when using libcurl multi-threaded.
unixsocket	Access HTTP server over Unix domain socket
url2file	Download a given URL into a local file named page.out.
urlapi	Set working URL with CURLU *.
usercertinmem	Use an in-memory user certificate and RSA key and retrieve an https page.
websocket	WebSocket using CONNECT_ONLY
websocket-cb	WebSocket download-only using write callback
xmlstream	Stream-parse a document using the streaming Expat parser.

You also find these examples in the distribution archive, in docs/examples.