How to Give Your Claude Agent an Email Inbox

The Problem

Your AI agent is running a signup automation flow. It creates an account on some service. The service sends a verification email. Your agent... stops cold. It can't open Gmail. It has no inbox. The flow is dead.

Agents don't have browsers. They need email as a primitive — an inbox they can create programmatically, wait on, and read from an API. That's what EmptyInbox is.

Option 1: MCP (One Config Line)

If you're using Claude Desktop or Claude Code, this is the fastest path. Add to your MCP config file:

{
  "mcpServers": {
    "emptyinbox": {
      "command": "npx",
      "args": ["-y", "emptyinbox-mcp"]
    }
  }
}

On first run, the server auto-registers and creates an account. No API key to copy, no dashboard to visit. Claude gets three tools immediately:

• create_inbox — generates a fresh @emptyinbox.me address
• wait_for_message — blocks until an email arrives (configurable timeout)
• list_messages — poll for messages across all inboxes

A full verification flow then looks like this:

You: Sign up for the Hacker News API with a throwaway address

Claude: Creating inbox...
→ address: "swift.copper.owl@emptyinbox.me"

Signing up at news.ycombinator.com with that address...
Waiting for verification email...
→ subject: "Please verify your email"
→ code: "847291"

Submitting verification code...
Done. Account active.

Claude handles the entire flow — no human in the loop, no browser tab, no copy-paste.

Option 2: REST API (Any Agent Framework)

For LangChain, CrewAI, GPT Actions, or custom Python/Node agents, use the REST API directly.

Step 1: Register (one-time)

curl -X POST https://emptyinbox.me/api/auth/register \
  -H "Content-Type: application/json" \
  -d '{"username": "my-agent"}'

# Response:
# {"api_key": "eiXXXXXXXXXXXXXXXX", "inbox_quota": 1}

Step 2: Create an inbox

curl -X POST https://emptyinbox.me/api/inbox \
  -H "Authorization: Bearer YOUR_API_KEY"

# Response (plain text):
# clever.sunny.butterfly@emptyinbox.me

Step 3: Trigger the signup, then poll for messages

curl https://emptyinbox.me/api/messages \
  -H "Authorization: Bearer YOUR_API_KEY"

# Response:
# [{"subject": "Confirm your email", "text_body": "Code: 482910", ...}]

If you're using GPT Actions or LangChain's OpenAPI tool loader, import the spec at /openapi.yaml and skip the manual curl setup entirely.

Free Tier

Human accounts start with 5 inboxes free. Agent accounts (registered via the API) start with 1 inbox — enough to test the full flow before scaling. When you need more, top up in batches of 10 for $1 USDT. No KYC, no credit card, no subscription.

Messages are auto-deleted after 7 days. No cleanup code needed.