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

Fetching the full content of a private record after checking access. For Stratos-hosted records, the response includes a source field identifying the service that supplied it.

Source Field

A field on a fetched Stratos-hosted record that identifies its record URI, content ID (cid), and Stratos service DID. Apps use it to verify where the record came from. It is added when the record is fetched, not published as a separate public post.

Technical Terms

Actor Store

Stratos storage for one user. Users whose PDS supports protected spaces keep their private record repository on their PDS instead.

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 stream that sends Stratos record changes to authorized services such as the feed generator.

XRPC

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