Why Nuncio Exists.
Local-first mail, calendar, and contacts, rebuilt without giving up control of your data. Nuncio is pre-alpha and under active, public reconstruction — this page is the vision alongside an honest read of what's actually built so far.
Breaking Away From Walled Gardens
For over a decade, personal and enterprise communication has been fractured across paid cloud subscriptions, closed proprietary formats, and locked-away data silos.
Nuncio is being built to eliminate those trade-offs. Created by James Maes (KofTwentyTwo), the goal is speed, sovereign data ownership, real encryption, and sane AI integration — each pillar below tagged with how far along it actually is.
1. Sane & Controlled AI / LLM Access
AI co-pilots should empower you, not exfiltrate your life. The plan is an RBAC gateway with capability flags, folder boundaries, and PII redaction before any payload reaches an LLM — none of it built yet.
2. First-Class UX in Every Interface
No second-class interfaces, by design: a desktop GUI, a keyboard-driven terminal TUI, a scriptable CLI, and an MCP AI bridge, all clients of one frozen gRPC contract. Only the CLI exists today.
3. A Fast, Native Engine
Built in Rust over single-writer SQLite WAL storage for real local performance, not a race against a specific number — see the feature matrix for what's measured versus aspirational.
4. Sovereign Control & Zero Closed Formats
No cloud lock-in, no proprietary sync servers. Your synced mail, accounts, and rules live in a local SQLite file you can export to standard MBOX, EML, or JSON at any time — that export path works today.
5. Zero-Trust Security & Encryption
Column-level encryption at rest, memory zeroing, and HTML sandboxing are the target. Today, credentials go through the OS keyring; message bodies are not yet encrypted at rest.
6. WORM Cryptographic Audits & Immutability
Real today: rule matches, webhook dispatches, and account mutations are recorded in an immutable, HMAC-SHA256 hash-chained audit ledger.
Open-Source Ecosystem Credits
Nuncio is made possible by the Rust, web, security, and open-protocol communities. Links go to each project's official repository.
Rust Core Systems & Data Storage
Async, pure-Rust SQL engine powering type-safe SQLite operations and migrations.
Pure Rust SQL lexer and parser powering the NSQL filter language compiler.
Event-driven asynchronous Rust runtime driving background IMAP sync and gRPC serving.
Serialization framework powering data models across every crate.
Ergonomic, type-safe Rust error handling used throughout the workspace.
Mail Protocols & Parsing
Security & Credential Storage
Web & Presentation Tooling
Open Protocols & Standards
The open stdio/JSON-RPC standard Nuncio's planned AI client will build on.
Open standards behind Nuncio's portable mail export formats.
Proof Key for Code Exchange, the target flow for OAuth-based providers.