MindMapVault builds real-time collaboration without server ever reading encrypted data

MindMapVault, an end-to-end encrypted mind mapping tool, encrypts all data in the browser using a key derived from the user's password, meaning the server only ever stores ciphertext. This design made real-time multi-user collaboration unusually difficult, since standard tools like Yjs require the server to parse document updates — which would compromise encryption. The team replaced the standard sync protocol with a custom one where every message is an opaque encrypted payload the server simply logs and relays without interpreting. Client-side compaction handles storage growth: a connected client periodically sends an encrypted snapshot that replaces the update log, effectively letting the server perform garbage collection on data it cannot read. The system runs on Cloudflare Durable Objects, with one globally unique instance per map, eliminating the need for Redis, lock services, or sticky sessions.