Core Concepts

Reading with an LLM? Give it this page as Markdown: https://nolag.app/docs/concepts.md

These are the building blocks every NoLag app is made of. Read them in order for a full mental model, or jump straight to the one you need.

In this section

Project Hierarchy explains how Projects, Apps, Rooms, and Topics fit together.
Topics & Pub/Sub covers the publish-subscribe model, topic patterns, and wildcards.
Rooms organize topics and manage message namespaces.
Presence tracks who is online and handles join and leave events in realtime.
Lobbies observe presence across many rooms at once.
Filters narrow message delivery to specific entities.
Quality of Service covers at-most-once, at-least-once, and exactly-once delivery.
Webhooks use hydration and trigger webhooks to integrate external systems.
Access Control provides fine-grained per-topic permissions.

Ready to build? Follow the Quick Start, or pick a Guide.