svelte-adapter-uws-extensions

The core adapter keeps everything in-process memory. That works great for single-server deployments, but the moment you scale to multiple instances you need shared state. This package provides drop-in replacements backed by Redis and Postgres - same API shapes you already know from the built-in plugins, distributed state.

What you get:

• Distributed pub/sub - platform.publish() reaches all instances, not just the local one
• Persistent replay buffers - messages survive restarts, backed by Redis sorted sets or a Postgres table
• Cross-instance presence - who is online across your entire fleet, with multi-tab dedup
• Distributed rate limiting - token bucket enforced across all instances via atomic Lua script
• Distributed broadcast groups - named groups with membership and roles that span instances
• Shared cursor state - ephemeral positions (cursors, selections, drawing strokes) visible across instances
• Database change notifications - Postgres LISTEN/NOTIFY forwarded straight to WebSocket clients
• Prometheus metrics - expose extension metrics for scraping, zero overhead when disabled

Installation

npm install svelte-adapter-uws-extensions ioredis

Postgres support is optional:

npm install pg

Requires svelte-adapter-uws >= 0.2.0 as a peer dependency.