Introduction

Stratos lets AT Protocol communities share posts with approved members. People keep their existing identities. A small enrollment record on each user's PDS helps apps find the service; private posts are not published in the public feed.

How It Works

1. A user enrolls with a Stratos service via OAuth. The service writes a zone.stratos.actor.enrollment record to the user's PDS.
2. The user creates a private post for a boundary. Stratos stores it for users whose PDS does not support spaces. Otherwise, the user's PDS stores it in a protected space, with Stratos managing membership.
3. The feed generator collects posts from Stratos and from PDS users whom Stratos lists as members. It verifies PDS updates before saving posts in its encrypted local database.
4. A viewer requests a feed with a signed service token. The feed generator checks the viewer's current Stratos membership and returns only posts they are allowed to read.

Repository Packages

Package	Description
stratos-core	Domain logic, storage interfaces, schema, validation, MST commit builder
stratos-service	HTTP/XRPC service, OAuth enrollment, repo CRUD, sync export, adapters
stratos-client	Discovery, routing, verification, and OAuth scope helpers
stratos-feedgen-ng	Feed generator with encrypted local storage and membership-checked feeds
webapp	Svelte demo client for enrollment and private posting
lexicons	JSON-based lexicon definitions

The TypeScript feedgen and AppView indexer remain in the repository for rollback or historical reference but are deprecated.

Architecture

For a deeper dive into the technical details of Stratos, see the following documentation:

• Reading Private Records — How apps fetch full private records after an access check.
• Feed Generator — How posts enter the encrypted local database and how access is checked.
• Enrollment Signing — How user keys and boundary attestations are managed.
• Multi-Domain Enrollment — How users can enroll in multiple boundaries across different services.

Next Steps

• Read the Glossary for key terms and concepts.
• Follow the First Post Tutorial to get started as a user.
• Follow the Client Integration Guide to add Stratos to your app.
• See the Operator Guide to deploy a Stratos service.
• Explore the Architecture for deep technical detail.