ContainSite by salmutt

Every website you visit is automatically placed in its own isolated container with a unique, deterministic device identity. Sites cannot share sessions, cookies, or correlate you through browser fingerprinting.

Features:
- Automatic per-site containers — no configuration needed
- 18 spoofed fingerprint vectors: Canvas, WebGL, AudioContext, Navigator, Screen, Timezone, WebRTC, Fonts, Font API, ClientRects, Plugins, Battery, Connection, HTTP Headers, Speech Synthesis, matchMedia, Performance Timing, Storage Estimate
- HTTP header spoofing — User-Agent, Accept-Language, and Client Hints per container
- Auth-aware — login redirects stay in the originating container
- Cross-site navigation automatically switches containers
- Options page to toggle individual vectors, whitelist domains, and manage containers

Works alongside Firefox Multi-Account Containers. No external dependencies.