Agent-native mailbox API (new, 2026)
The Best Robotomail Alternative for AI Agents
Robotomail is a genuinely agent-native two-way mailbox API, new in 2026. Lumbox covers the same agent-owned inbox and adds OTP-to-JSON, long-poll /otp, a credential vault, IMAP and 77 MCP tools — and has more of a track record.
Robotomail is a genuinely agent-native mailbox API: one API call creates a mailbox with a real address, an agent can self-onboard via a /skill page and a single POST, and you get two-way send and receive, inbound over HMAC-signed webhooks, SSE or polling, automatic threading, custom domains with auto DKIM/SPF/DMARC, attachments and per-mailbox guardrails over a REST API and CLI. Its honest edge is a simple, cheap, genuinely agent-owned two-way inbox. It does not document or advertise OTP / verification-code extraction, an MCP server, first-party SDKs or a credential vault, so an agent that needs those builds them itself. It is also very new (launched around May 2026) with no reviews, funding or team signals and no SOC 2, and a human still has to create the account and API keys before the agent operates. Lumbox's edge is OTP / magic-link / backup-code extraction to JSON, a long-poll /otp endpoint, an encrypted AES-256-GCM credential vault, IMAP, 77 native MCP tools, self-hosting and being more proven.
Lumbox vs Robotomail: feature comparison
| Capability | Lumbox | Robotomail |
|---|---|---|
| Creates agent-owned inboxes (no human OAuth) | ||
| Automatic OTP / magic-link / backup-code extraction to JSON | ||
| Long-poll endpoints (/otp, /wait) — no polling loops | ||
| IMAP access (read inboxes from any mail client) | ||
| Native MCP tools (Claude Code, Cursor) | ||
| Encrypted credential vault (AES-256-GCM) | ||
| Custom domains with auto DKIM / SPF / DMARC | ||
| Self-hostable |
full · partial / DIY · not available
Where Robotomail falls short for agents
- Does not document or advertise automatic OTP / magic-link / backup-code extraction — the agent parses raw email itself.
- Does not document an MCP server, first-party SDKs or a credential vault.
- Very new (launched around May 2026) with no reviews, funding or SOC 2 yet, and a human must create the account and API keys before the agent runs.
What Lumbox adds
- OTPs, magic links and backup codes extracted to JSON, with a long-poll /otp endpoint that returns just the code.
- Encrypted AES-256-GCM credential vault, IMAP access and 77 native MCP tools for Claude Code and Cursor.
- Self-hostable and more proven, with the full inbound-and-identity stack rather than a two-way inbox alone.
When to choose Robotomail instead
Lumbox isn't the right tool for every job. Pick Robotomail when:
- You want a minimal, cheap two-way agent inbox and don't need OTP extraction, a vault, MCP or IMAP.
- You're comfortable running on a brand-new service without reviews, funding or SOC 2 yet.
- Self-onboarding an agent over a /skill page and a single POST is the main thing you care about.
Robotomail alternative — frequently asked questions
What is the difference between Robotomail and Lumbox?
Both create agent-owned inboxes with two-way send and receive and custom domains. Robotomail's edge is a simple, cheap, genuinely agent-owned inbox. Lumbox adds OTP / magic-link / backup-code extraction to JSON, a long-poll /otp endpoint, an AES-256-GCM credential vault, IMAP and 77 native MCP tools, and is more proven.
Does Robotomail extract OTP codes or include an MCP server?
Robotomail does not document or advertise OTP / verification-code extraction, an MCP server, first-party SDKs or a credential vault. If your agent needs those, Lumbox provides OTP-to-JSON, a long-poll /otp endpoint, a credential vault and 77 native MCP tools out of the box.
Is Robotomail or Lumbox better for a new project?
Choose Robotomail for a minimal two-way agent inbox when you don't need OTP extraction, a vault, MCP or IMAP and are comfortable on a brand-new service. Choose Lumbox when you need OTP handling, a credential vault, MCP tools, IMAP, self-hosting or a more proven platform.
Give your agent its own inbox
Free during beta. One POST to create an inbox, one GET to get an OTP.
Start freeCompare more tools on the email API for AI agents overview.