> For the complete documentation index, see [llms.txt](https://soundprotocol.gitbook.io/soundprotocol/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://soundprotocol.gitbook.io/soundprotocol/discovery-node/discovery-api-interfaces.md).

# Discovery API interfaces

SoundProtocol will produce a first-party discovery API interface, but other community members are encouraged to author their own interfaces that extend or modify the core API. The protocol allows fans to select any discovery API interface registered in the SoundProtocol content ledger.

An API interface must index new blocks from the SoundProtocol ledger atomically (i.e. all-or-nothing), and all API methods must be deterministic. Because of these requirements, for a given block hash, all discovery nodes running a given API interface will produce identical results for the same query.