BYOD

Bring your own domain. Own your agent mailboxes.

BYOD gives Claude Code (or any MCP client) email addresses on a domain you own: signup@yourname.xyz, invoices@yourname.xyz, as many as you like. Agents create them, read what arrives with the codes and links already picked out, wait for a verification email, save attachments, and reply or send with files from your computer.

The mail lands in a Cloudflare Worker in your own Cloudflare account and is stored there, in a Durable Object only you can reach. The MCP server runs on your machine. There is no account to sign up for, and nothing passes through anyone else.

What you need

• A domain. A .xyz on Spaceship is usually a dollar or two for the first year (check the renewal price).

• A free Cloudflare account. Receiving mail works on the free plan. Sending to any address needs Cloudflare's Workers Paid plan ($5 a month).

• Node.js 20 or newer.

Related MCP server: email.deadsimple/dead-simple-email

Set it up

1. Buy a domain on Spaceship

Search for a name on spaceship.com, sort by price, buy the cheapest one you like. Any name works; it only has to be yours.

2. Move its DNS to Cloudflare

1. In Cloudflare, Add a domain, type it in, pick the Free plan and continue. Cloudflare shows two nameservers, like ada.ns.cloudflare.com and bob.ns.cloudflare.com.

2. In Spaceship, open Advanced DNS and pick the domain. Under Nameservers, click Change, choose Custom nameservers and confirm, paste Cloudflare's two in place of Spaceship's, and Save. This ends Spaceship's own email forwarding or hosting on that domain, which is what you want.

3. Wait for Cloudflare to say the domain is Active. It is often minutes, at most 48 hours.

3. Deploy your Worker

npx -y github:brandonmlicea/byod setup yourname.xyz

It signs you in to Cloudflare with Wrangler the first time, deploys the byod Worker to your account, sets a random secret token on it, and saves the Worker's address and token to ~/.byod/config.json (readable only by you). Give several domains to use them all: setup yourname.xyz other.dev. Run it again any time to update; the token stays the same.

4. Two switches in the Cloudflare dashboard

For each domain:

1. Receive: Compute > Email Service > Email Routing > Onboard Domain. Then Routing rules > Catch-all address > Edit > action Send to a Worker > byod > Save, and make sure the catch-all is on.

2. Send (Workers Paid): Compute > Email Service > Email Sending > Onboard Domain. Cloudflare adds the SPF, DKIM and DMARC records itself.

5. Add it to Claude Code

claude mcp add byod -- npx -y github:brandonmlicea/byod

Any other MCP client (Claude Desktop, Cursor, Codex...):

{
  "mcpServers": {
    "byod": { "command": "npx", "args": ["-y", "github:brandonmlicea/byod"] }
  }
}

To point it somewhere else, set BYOD_URL and BYOD_TOKEN instead of the config file.

Tools

Try it

• "Make me a mailbox for signing up to Figma, sign up with it, and paste me the confirmation code."

• "Create invoices@ and tell me when something arrives there."

• "Reply to the last email in support@ saying we'll ship Friday, and attach ~/Desktop/quote.pdf."

How it behaves

• Mail to an address that is not a mailbox is refused, so the catch-all never collects spam. name+anything@ goes to name@.

• Mail always leaves from one of your mailboxes; nothing an agent passes can set another From.

• The API answers only to your token, compared in constant time.

• Each mailbox keeps its last 1,000 messages. Inbound mail is capped at 10 MB.

• Sending: 50 recipients an email, 10 files and about 3.5 MB of attachments, and 100 emails a day by default (DAILY_LIMIT in worker/wrangler.jsonc), so a runaway agent cannot burn your domain's reputation.

• Expired mailboxes are deleted with their mail the next time the Worker is used.

Check it

npm install
npm test        # the code and link picker on labelled cases
npm run e2e     # the Worker in wrangler dev and the MCP server, end to end

npm run e2e runs everything on your machine: it sends real MIME messages into a local Worker, reads them, waits for one, saves an attachment, replies and deletes, through the MCP server.

Remove it

Delete the byod Worker in Cloudflare (Workers & Pages), which deletes its mail, and ~/.byod.

License

MIT