Atomic Mail Agentic is an email provider built by Atomic Mail for autonomous AI agents, with the goal of enabling agents to autonomously read, send, and respond to email without any human intervention throughout the process.
Purpose Agents can register their own @atomicmail.ai inbox and manage it end to end, without manual setup, verification, or ongoing intervention. Users only need to describe the workflow in natural language, and the agent can complete tasks such as registering an address, sending and receiving email, and maintaining conversations, without needing to configure scripts, copy API keys between tabs, or remember JMAP details.
Key capabilities
- A full mailbox API based on JMAP (RFC 8620): read and send email, create drafts, manage conversations, search, and more. JMAP is widely present in LLM training data, and models are relatively familiar with its request format, which can reduce retries and improve automation reliability.
- Access is controlled through a proof-of-work (PoW) registration protocol, with strong anti-abuse properties, no CAPTCHA or manual approval required, and agents can join and operate completely hands-free.
- Standard integration paths: MCP, AgentSkill, REST API, etc., usable with agents such as Claude Code, Codex, GitHub Copilot, Cursor, Hermes, OpenClaw, Pi, Kilo Code, and others.
- This repository provides client integrations: MCP, shell CLI, ClawHub, Dify plugin, etc., exposing the API through the three tools register, jmap_request, and help. The connectors in the repository are relatively lightweight and are mainly used to abstract the complexity of the PoW protocol.
- Built-in recovery mechanisms: help provides embedded documentation (presets, cron, troubleshooting), bundled JSON presets cover common operations, and error messages include hints for the next thing to try.
- Presets cover common operations such as send_mail, list_inbox, reply, etc.; when raw JMAP is too cumbersome, a filename can be passed to jmap_request instead of generating the method call JSON from scratch.
- The same authentication, JMAP, preset, and help stack drives both MCP and AgentSkill; when running multiple agents, each inbox has its own credentials directory.
How to use
- Ready-made prompt for use in any agent: add the corresponding configuration to MCP host configuration (or have the agent do it directly), then restart the host and have the agent create an inbox.
- For custom connectors and advanced logic, refer to the documentation docs/rest-auth.md.
- Custom domains: by default the inbox is located at <name>@atomicmail.ai, registered via PoW without manual creation. If you need to send from your own domain (e.g. support@yourcompany.com), you need to set it up once in the dashboard, which is a manual control plane independent of the agent flow, because it requires modifying the DNS of your own domain. Add and verify the domain in the dashboard (TXT ownership record + MX record; can be run repeatedly, propagation usually takes only a few minutes), then create an inbox on it—each inbox gets a full address (agent@yourcompany.com) and an API key from the Connect dialog, and uses a From signature aligned with the domain when sending. The client is unchanged: the same jmap_request, presets, and JMAP structure. A custom domain inbox is a login rather than a PoW registration: you can connect with its API key (atomicmail register --api-key "…") or OAuth. $INBOX resolves to the real address (agent@yourcompany.com), so self-addressing and From remain correct without extra configuration. See docs/custom-domains.md for the full guide.
Use cases
- Newsletter summaries: give the agent a dedicated inbox, subscribe to newsletters, read all content, and summarize daily digests related to AI tools as needed, without touching a personal mailbox.
- Support inbox: monitor support@ and reply to tickets based on documentation, escalating to the user only when unable to answer.
- User research interviews: conduct asynchronous interviews via email, send questions, follow up based on replies, and summarize findings; respondents can reply on their own schedule without scheduling a call.
Limitations
- The default account is free, includes a 100 MB storage quota, custom domains, and rate limits suitable for agent workloads (specific rate values are not provided in the materials).
- Custom domains require the user to make DNS changes on their own domain and cannot be fully completed manually-free by the agent.
- Local development requires Node.js 20+, Deno 2.7+.
- ~/.atomicmail/credentials.json contains the API key and should be treated as confidential; the local credentials file is written with 0600 permissions.
- Inbound email is untrusted input, and the agent should not be allowed to execute instructions in emails without confirmation.
- Install only from the @atomicmail npm scope.
- If the repository documentation is inconsistent with the installation behavior, the help for the same version as the installed package being run should prevail.
Other The service is backed by a continuously warmed IP pool with relay overflow to ensure deliverability. JMAP is an IETF standard, and the inbox can be migrated to any compatible provider in the future, avoiding vendor lock-in. Community projects such as atomic-mail-watcher provide a Docker-ready JMAP inbox listener with Telegram/webhook notifications. PRs are welcome; new features and bug fixes are suggested to be covered by automated Deno tests, and user-facing documentation should be updated when behavior changes; see CONTRIBUTING.md for more details.
