====== Developer documentation ======
This section describes ApuOS APIs, ApuSync transfers and the SPKG package format. Read the security and compatibility requirements before writing a client or package.

* [[developer/http|HTTP API conventions]]
* [[developer/transfers|File transfer API]]
* [[developer/sync-photos|Photo synchronization contract]]
* [[packages/manifest|SPKG manifest and schema]]
* [[packages/publishing|Package publishing and review]]

Every client must verify HTTPS, pairing identity, request scope, response size and final content hashes. Every package must declare its host version, architecture, permissions, source and signature metadata.