Editing Data repository (section)

== Architecture ==
Repositories are built on a [[Merkle Search Tree (MST)]] data structure, which reduces the entire state to a single root hash. 

The repository structure consists of three main layers:

* '''Commit''': The signed root that authenticates the entire repository
* '''Tree Nodes''': The internal structure organizing the data
* '''Records''': The actual content (posts, likes, follows, etc.)

Each element in this structure is a [https://ipld.io/specs/codecs/dag-cbor/spec/ DAG-CBOR] object referenced by a [[Content Identifier (CID)]] hash.

Repositories can be synchronized across multiple PDSes, allowing users to maintain multiple distributed copies of their data.

Content within repositories can be addressed using [[AT URI|AT URIs]], which follow a hierarchical pattern:<syntaxhighlight lang="text">
at://alice.com                      # Repository root
at://alice.com/app.bsky.feed.post   # Collection
at://alice.com/app.bsky.feed.post/1234  # Specific record
</syntaxhighlight>