This is the latest version of the API (Application Programming Interface) for CiviCRM. If you are here because you're trying to install an extension that requires this, just install this and you're done!

If you are a developer, read on...

Once installed you can navigate to Support -> Developer -> Api4 Explorer in the menu. This gives a live, interactive code generator in which you can build and test api calls:

The php binding returns an arrayObject. This gives immediate access to the results, plus allows returning additional metadata properties.

$result = \Civi\Api4\Contact::get()->execute();

// you can loop through the results directly
foreach ($result as $contact) {}

// you can just grab the first one
$contact1 = $result->first();

// reindex results on-the-fly (replacement for sequential=1 in v3)
$result->indexBy('id');

// or fetch some metadata about the call
$entity = $result->entity; // "Contact"

We can do the something very similar in javascript thanks to js arrays also being objects:

CRM.api4('Contact', 'get', params).then(function(result) {
  // you can loop through the results
  result.forEach(function(contact, n) {});

  // you can just grab the first one
  var contact1 = result[0];

  // or fetch some metadata about the call
  var entity = result.entity; // "Contact"
});

• Api wrapper
  • In addition to the familiar style of civicrm_api4('Entity', 'action', $params) there is now an OO style in php \Civi\Api4\Entity::action().
  • When chaining api calls together, backreferences to values from the main api call must be explicitly given (discoverable in the api explorer).
  • $checkPermissions always defaults to TRUE. In api3 it defaulted to TRUE in REST/Javascript but FALSE in php.
  • A 4th param index controls how results are returned: Passing a string will index all results by that key e.g. civicrm_api4('Contact', 'get', $params, 'id') will index by id. Passing a number will return the result at that index e.g. civicrm_api4('Contact', 'get', $params, 0) will return the first result and is the same as \Civi\Api4\Contact::get()->execute()->first(). -1 is the equivalent of $result->last().
• Actions
  • Get no longer sets a default limit of 25 outside the api explorer.
  • Use the Update action to update an entity rather than Create with an id.
  • Update and Delete can be performed on multiple items at once by specifying a where clause, vs a single item by id in api3.
  • getsingle is gone, use $result->first() or index 0.
  • getoptions is no longer a standalone action, but part of getFields.
• Input
  • Instead of a single $params array containing a mishmash of fields, options and parameters, each api4 parameters is distinct. e.g. for the Get action: select, where, orderBy and limit are different params.
  • Custom fields are refered to by name rather than id. E.g. use constituent_information.Most_Important_Issue instead of custom_4.
• Output
  • Output is an array with object properties rather than a nested array.
  • In PHP, you can foreach the results arrayObject directly, or you can call methods on it like $result->first() or $result->indexBy('foo').
  • By default, results are indexed sequentially like api3 sequential => 1, but the index param or indexBy() method let you change that. e.g. civicrm_api4('Contact', 'get', $params, 'id') or \Civi\Api4\Contact::get()->execute()->indexBy('id') will index results by id.

Each action object has a $checkPermissions property. This always defaults to TRUE, and for calls from REST it cannot be disabled.

• An Entity is a class implementing one or more static methods (get(), create(), delete(), etc).
• Each static method constructs and returns an Action object.
• All actions extend the AbstractAction class. A number of other abstract action classes build on this, e.g. AbstractBatchAction is the base class for batch-process actions (delete, update, replace).
• Most entity classes correspond to a CRM_Core_DAO subclass. E.g. Civi\Api4\Contact corresponds to CRM_Contact_DAO_Contact.
• A set of DAO action classes (e.g. DAOGetAction, DAODeleteAction) exists to support DAO-based entities. DAOGetAction uses Api4SelectQuery to query the database.
• A set of Basic action classes (e.g. BasicGetAction, BasicBatchAction) exists to support many other use-cases, e.g. file-based entities.
• The base action execute() method calls the core civi_api_kernel service runRequest() method which invokes hooks and then calls the _run method for that action.
• Each action object has a _run() method that accepts and updates a Result object (which is an extended ArrayObject).

To alter the behavior of an existing entiy action, use hook_civicrm_apiWrappers.

Create a class which extends a generic action class (see below). Give it the same namespace and file location as other actions for that entity. It will be picked up automatically by api4's getActions file scanner.

If your entity has a database table and DAO, simply add a class to the Civi/Api4 directory of your extension. Give the file and class the same name as your entity, and extend the DAOEntity class.

For specialty apis, try the BasicGet, BasicCreate, BasicUpdate, BasicBatch and BasicReplace actions as in this example.

Tests are located in the tests directory (surprise!) To run the entire Api4 test suite go to the api4 extension directory and type phpunit4 from the command line.