---
title: "Pubky Moderation"
---

Content moderation service for the Pubky ecosystem, designed to protect [homeserver](https://pubky.org/explore/pubkycore/homeserver.md) operators and users from harmful content. Monitors events from homeservers and [Nexus](https://pubky.org/explore/pubky-apps/indexing-and-aggregation/pubky-nexus.md), sends content to [Checkstep](https://www.checkstep.com/) for moderation, and enforces policy decisions.

- **Repository**: https://github.com/pubky/pubky-moderation
- **Language**: Rust

## Philosophy

- **Per-homeserver/indexer only**: Actions affect a single homeserver's content, not identity or data on other homeservers.
- **Operator choice**: Each homeserver decides whether to run moderation services.
- **Replaceable**: Anyone can run their own moderation stack with different policies.

## Moderation Flows

1. **Homeserver moderation**: Raw media content at `<public key>/` (except `pubky.app/`). Syncs homeserver `/events/`, resolves pubky resources to HTTPS URLs, and submits to Checkstep. Enforces decisions via homeserver admin API.

2. **Nexus moderation**: Social content at `<public key>/pubky.app/`. Syncs [Nexus](https://pubky.org/explore/pubky-apps/indexing-and-aggregation/pubky-nexus.md) `/v0/events`, parses social entities (profiles, posts, tags, threads), and sends to Checkstep with partial content support. Enforces via moderation bot tagging and homeserver admin API.

## Architecture

Both flows are implemented as a Rust workspace with multiple long-running services and a shared PostgreSQL database:

```
Homeserver/Nexus Events -> Sync Services -> PostgreSQL -> Request Service -> Checkstep API
                                                                            |
Homeserver Admin API <- Response Service (webhook) <- Checkstep Decision
```

Each sync service runs with cursor-based pagination, exponential backoff, and graceful shutdown handling.

## Resources

- [Repository with workspace layout and setup](https://github.com/pubky/pubky-moderation)
- [Checkstep documentation](https://docs.checkstep.com/standard/)