Delta Chat, decentralized secure messenger - Delta Chat | WarmIndex

Delta Chat is a free, open-source decentralized messenger that uses standard email (IMAP/SMTP) infrastructure for secure, end-to-end encrypted instant messaging without requiring phone numbers or central servers, perfect for privacy-focused individuals, families, groups, and organizations.

🚀 Overview

Delta Chat is a secure, cross-platform messenger app that transforms standard email into a fast, reliable chat experience. Instead of relying on proprietary servers like WhatsApp or Signal, it uses your existing email account or free "chatmail" relays for message delivery, ensuring decentralization and interoperability.

What problem does this project solve? Centralized apps collect metadata, mandate phone numbers, limit multi-device use, and risk shutdowns or policy changes by companies. Delta Chat provides instant messaging with audited E2EE, working with any email provider for true privacy and resilience.

Who is it built for? It's for everyday users, friends and family, activist groups, and organizations who want simple, secure communication without big tech oversight.

Why did you build it? The open-source community created Delta Chat to reclaim messaging on internet standards, funded by grants, donations, and public money—no venture capital involved—ensuring it's free forever and resistant to censorship.

✨ Key Features

Reliable instant messaging via email protocols with push notifications and multi-device/multi-profile support
End-to-end encryption by default using Autocrypt (multiple independent audits: 2019, 2020, 2023, 2024)
No phone number or new signup needed—uses any IMAP/SMTP email account
Interactive web apps shared in chats for collaboration, gaming, and tools
Optional: Upcoming Autocrypt v2 and P2P video calls via calls-webapp

🛠 Tech Stack

Core: Rust (deltachat-core-rust)
Android: Java (deltachat-android)
iOS: Swift (deltachat-ios)
Desktop: TypeScript (deltachat-desktop)
Protocols: IMAP/SMTP (async-email libs), OpenPGP (rPGP)
Auth: Email provider credentials
Hosting: App stores, F-Droid, Microsoft Store, direct downloads

👥 Who Is This For?

This project is useful for:

Privacy-conscious users who want decentralized, E2EE chat without phone numbers
Teams and organizations looking for interoperable, server-independent communication
Indie users and activists building censorship-resistant networks

📸 Screenshots / Demo

Live demo: https://get.delta.chat (download for mobile/desktop)
GitHub: https://github.com/deltachat

🔥 Project Status

🟢 Actively building

Last updated: 2026-03-24

❓ FAQ

Is this project free?

Yes — free and open source software for apps and servers, no ads, tracking, or subscriptions.

Is the source code available?

Yes — https://github.com/deltachat (main org with 68 repos, including deltachat-core-rust, -android, -ios, -desktop)

Can I contribute?

Yes — help via GitHub issues/PRs (many "good first issue"), translations on Transifex, donations, testing, or forums. See https://delta.chat/en/contribute