chatmail.at

What It Is

Chatmail is not a traditional email marketing provider. It is a community-driven FOSS open-source infrastructure project that aims to make email feel more like instant messaging while strengthening security and interoperability. It mainly consists of the chatmail/relay relay deployment template and the chatmail/core Rust library, serving relay operators, chat app developers, bot developers, and their users.

Core Capabilities

At the transport layer, Chatmail is still based on email, but it uses email for instant message delivery and supports optional temporary peer-to-peer real-time messaging. On the security side, the project emphasizes automatic end-to-end encryption, metadata minimization, and temporary transmission only, without long-term storage. relay can automatically deploy a minimal MTA that only transmits end-to-end encrypted, metadata-minimized Internet Messages, and it communicates with other MTAs through cryptographic interoperability standards, reducing reliance on IP reputation and anti-spam mechanisms.

API, Integrations, and Performance

chatmail/core is a cross-platform Rust infrastructure library designed for chat app and bot integrations. It provides a high-level JSON-RPC API for managing contacts and chats, and for sending and receiving instant messages via email and P2P real-time messaging. Its lower-level capabilities include secure TLS configuration, DNS caching, SMTP/IMAP connection handling, MIME and OpenPGP parsing and message construction, as well as the Iroh P2P network. The source text does not disclose quantified delivery rates, latency, or throughput data, but it highlights reliable connection handling and resilience features.

Pricing, Pros, and Cons

The source text does not provide commercial subscription pricing or payment methods. Its cost information is closer to a self-hosted operations model: the hosting cost for 100K relay users is about half a US cent per user per year, and system administration costs are close to zero after deployment. Its strengths are that it is open source, low-cost, clearly designed around security, and suitable for interoperable communications. Its drawbacks are that it is more of a lower-level infrastructure component, lacking a ready-to-use dashboard, SLA, customer support, compliance certifications, and delivery-rate metrics, so it requires a technically capable team.

Who It’s For and Access from China

Chatmail is suitable for developers and community projects that want to build secure instant email chat, decentralized communications, bot messaging systems, or low-cost relay networks. It is less suitable for businesses that simply want to buy marketing email, transactional email, or SMS services. Access from mainland China is not specified in the source text; network connectivity, payment methods, and alternatives need to be tested independently. If you need a mature commercial email API, compare it with Mailgun, SendGrid, or Postmark. If you care more about instant messaging, consider Matrix, Signal, or Delta Chat.