Extensions are installable packages which give CiviCRM new functionality, and this directory provides a centralized list of extensions which the CiviCRM community has created.

Further resources:

Mobile application for few specific actions in CiviCRM Current feature includes: * Contacts - Search Contacts - Add/Update/View Contacts - Proximity search for contacts * Events - participant search and checkin * Survey - Search for suvery - Record survey responses    ...
Current Usage: 581
This extension allows CiviCRM to send emails and process bounces through the SparkPost service. It was designed with the following goals and/or features:...
Current Usage: 580
Allows Drupal's cron to invoke CiviCRM's cron.
Current Usage: 530
This extension adds the possibility to export directly into the MS Excel (.xlsx) format, instead of CSV (less fiddling, easier to use). It supports exporting from reports and from search results....
Current Usage: 526
Twilio and CiviCRM integration allows delivering single and mass short message service (SMS) messages through its Twilio Gateway to mobile phone users. Download Link: https://github.com/civicrm/org.civicrm.sms.twilio/releases/latest...
Current Usage: 522
CiviRules is an extension that allows rules based actions, like automatically adding a contact to a group when he/she contributes more than
Current Usage: 514
This is a payment processor extension for the iATS Payments payment processing service, making use of the web services interface.
Current Usage: 494
Displays CiviCRM events in a calendar using the "fullcalendar" jQuery plugin.
Current Usage: 483
Provides integration with Clickatell SMS gateway for sending single and mass messages.
Current Usage: 449
This extension provides additional mail merge tokens for CiviCRM for use in emails, mass emails, or PDF letters....
Current Usage: 438
Sometimes CiviCRM can be real tough to debug. Especially when you are getting fatal errors, but only by some users, and you can't recreate the problems. This utility will send you a detailed email when a CiviCRM fatal error occurs....
Current Usage: 392
Once installed, an 'API Key' tab will be available on contact screens for which you are authorized to manage the API key for this contact. You are authorized either if the contact if yourself, or if you are an administrator with the 'edit all contacts' permission....
Current Usage: 379
This extension loads United States counties when you first install it.  Once enabled, it does nothing.  You may disable it or uninstall it, and nothing will happen: the counties will remain loaded in your database.  If you re-enable it, it will check for missing counties and just add those....
Current Usage: 305
Provides WordPress widgets for a single event or a list of events, in the sidebar or with shortcodes.
Current Usage: 300
This extension facilitates uploading CSVs via the CiviCRM import interface. Useful for bulk uploading events or campaigns etc. The civicrm api entity can be set to, for example, Event or Campaign. (Note that for entities like Contribution Pages you need to use API names - either ContributionPage or contribution_page). The same permissions apply as for any api create call....
Current Usage: 293