Editing XPRC

'''XPRC''' is the standardized HTTP API convention used throughout the [[AT Protocol]] for client-server and server-server communication. It provides a consistent way for applications to interact with [[Personal Data Server (PDS)|Personal Data Server (PDSes)]], [[Relay|relays]], [[AppView|AppViews]], and other services in the [[ATmosphere]].

XPRC enables a wide range of interactions within the AT Protocol, such as fetching and creating content, managing user accounts and profiles, synchronizing [[Data repository|data repositories]] between services, uploading [[Blob|blobs]], and facilitating user interactions.

== Structure ==
XPRC requests follow a simple pattern:

* All API endpoints begin with <code>/xprc/</code> followed by a [[Namespaced Identifier (NSID)]]
* The NSID identifies the specific [[lexicon]] schema that defines the request and response formats
* Requests are either ''queries'' (HTTP GET) or ''procedures'' (HTTP POST)

For example, a request to fetch a user's profile might look like:<syntaxhighlight lang="text">
GET /xrpc/app.bsky.actor.getProfile?actor=alice.bsky.social
</syntaxhighlight>

== Key Features ==

=== Request Types ===
XPRC supports two primary request types:

* '''Queries''' (HTTP GET): Used for retrieving data without changing server state
* '''Procedures''' (HTTP POST): Used for operations that modify data or state

The distinction follows standard HTTP [[wikipedia:REST|REST]] semantics, with queries being cacheable and procedures being non-cacheable.

=== Parameters and Data (WIP) ===

* '''URL Parameters''': Simple data types passed in the URL query string
* [[Blob|'''Blobs''']]: Binary data like images handled through specialized upload/download endpoints

=== Authentication ===
XPRC uses several authentication methods:

* '''[[OAuth]]''': The primary authentication method for client applications
* '''[[wikipedia:JSON_Web_Token|JWTs]]''': Used for session management and service-to-service communication
* '''[[App Passwords]]''': Special credentials that provide limited access for third-party applications

=== Pagination ===
For endpoints that return large sets of data, XPRC uses [[wikipedia:Cursor_(databases)|cursor]]-based pagination. Initial requests are made without cursor parameters. If more data is available, the response will include a cursor value that must be included in follow-up requests to retrieve the next batch of data. This continues until no cursor is returned, indicating the end of the dataset.