Stratos

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Glossary ​

This glossary defines key terms and concepts used across the Stratos project.

Core Concepts ​

Boundary ​

A service-qualified identifier in {serviceDid}/{name} format (e.g., did:web:stratos.example.com/engineering). Records in Stratos have boundaries, and a viewer must be enrolled in at least one of those boundaries to access the record.

Enrollment ​

The process by which a user registers with a Stratos service via OAuth. This results in an enrollment record being published to the user's PDS, which downstream services use for discovery and verification.

Hydration ​

The process where a client or AppView fetches the full content of a Stratos-backed record. Because Stratos records are private and live only in the user's per-actor repo on Stratos, hydration resolves a record reference into its full content after verifying access controls, returning it with a source field.

Source Field ​

A field returned on a hydrated record that specifies where the full record is located. It includes the uri of the record in Stratos, the cid for verification, and the service DID of the Stratos instance. Stratos does not write per-record stubs to the user's PDS; the source field is attached at hydration time.

Technical Terms ​

Actor Store ​

The per-user storage within Stratos that holds records, blobs, and repository metadata for a specific DID.

MST (Merkle Search Tree) ​

A data structure used by AT Protocol to represent a repository's state. Stratos uses MSTs to maintain per-actor repositories that are compatible with AT Protocol's sync primitives.

Service DID ​

The decentralized identifier for the Stratos service itself (e.g., did:web:stratos.actor). It is used to sign enrollment attestations and as the source.service reference on hydrated records.

subscribeRecords ​

A WebSocket sync stream provided by Stratos (and the PDS) that allows indexers to receive real-time updates about record creations, updates, and deletions.

XRPC ​

The AT Protocol's remote procedure call mechanism used for communication between clients, PDSs, and services like Stratos.