Connect your agent to the outside world.
AI agents can reason, plan and write, but most of them have no address. People cannot write to them, and services they need to sign in to send the login code somewhere the agent never sees. Lumbox gives an agent its own inbox and the tools to act on what arrives there.
What we build
Each agent on Lumbox gets its own email inbox, on our domain or yours. Every message is parsed to JSON when it arrives and threaded with the ones before it. The agent reads it, replies or forwards, signs in with the codes and magic links it receives, and calls your own HTTP tools when it needs data from your systems.
You can connect the agent you already run through the REST API, the Node and Python SDKs, or 104 MCP tools for Claude Code and Cursor. You can also build the agent on Lumbox: give an inbox instructions, a knowledge base and your tools, then choose whether its replies go out on their own or wait as drafts for you to approve.
For logins there is an encrypted credential vault for passwords and 2FA secrets, plus a stealth browser. Custom domains come with DKIM, SPF and DMARC, and you also get webhooks plus IMAP and SMTP access. You can forward texts from your own phone into an inbox today, and dedicated phone numbers for agents are in early access.
Who builds it
Lumbox is built by Deepanshu Kumar, an engineer who kept hitting the same wall while building agents: the agent was ready to act, but had no inbox of its own, so nobody could reach it and it could not get past a login code. Rather than rebuild a mail server for every project, he turned the missing piece into a product.
It is built in public. You can follow the work and reach the founder directly on X (@kumard_3) and GitHub. Support questions go straight to a human at support@lumbox.co.
How it runs
The API and mail server run on dedicated hardware in Germany (Hetzner). The database is Postgres on Supabase in Frankfurt, and this site sits behind Cloudflare. Sensitive data is encrypted at rest with AES-256-GCM, and the credential vault uses envelope encryption with a separate key per organization, so we cannot read what you store. We do not sell your data, and we never use your email content to train AI models.
If you would rather own the whole stack, Lumbox is self-hostable and runs on a $5 server. Full detail on how we protect data lives on the security page.
A note on the name
Lumbox started life as AgentMailr. We rebranded in March 2026 after a trademark notice, but the product, API, and inboxes are unchanged. The full story is on the rebrand page.