Email Warm-up API and MCP server

Building an AI SDR, Clay table or n8n workflow? Start with Warm-up API for AI SDRs and outbound agents.

Free with every BobWork Email Warm-up account. Connect mailboxes, watch warm-up health, check SPF, DKIM and DMARC, and run Outbound campaigns from your own code, from Zapier or Make, or straight from an AI assistant such as Claude, ChatGPT or Cursor through MCP.

Quick start

1. Sign in at app-emailwarmup.bobwork.ai (free, no card).
2. Open API in the sidebar and create a key. It starts with bwk_ and is shown once.
3. Send it as a Bearer token. JSON in, JSON out. Base URL: https://app-emailwarmup.bobwork.ai/api/v1

An AI agent can do steps 1 and 2 without a browser: POST https://app-emailwarmup.bobwork.ai/api/v1/signup/code with the person's email, read the 6-digit code from that inbox, then POST https://app-emailwarmup.bobwork.ai/api/v1/signup/verify to get the key. See the agent guide and the OpenAPI spec.

curl https://app-emailwarmup.bobwork.ai/api/v1/mailboxes \
  -H "Authorization: Bearer bwk_YOUR_KEY"

Connect mailboxes by API

Three ways, the same as in the app. Every connection is tested before it is saved, and warm-up starts the same day.

Any IMAP/SMTP mailbox (Gmail with an app password, Yahoo, iCloud, Lark, custom domains, SES, SendGrid, Mailgun). Use a preset from GET /providers, or give the hosts yourself.

curl -X POST https://app-emailwarmup.bobwork.ai/api/v1/mailboxes/imap \
  -H "Authorization: Bearer bwk_YOUR_KEY" -H "Content-Type: application/json" \
  -d '{"email": "sales@yourdomain.com", "password": "APP_PASSWORD", "preset": "gmail-imap", "name": "Sam"}' 

Gmail / Google Workspace with Google sign-in. Ask for a link, open it, sign in and allow. The mailbox appears in GET /mailboxes a few minutes later.

curl -X POST https://app-emailwarmup.bobwork.ai/api/v1/mailboxes/google/link -H "Authorization: Bearer bwk_YOUR_KEY"

Zoho Mail, free plan included. Create a Self Client at api-console.zoho.com, generate a code, and send the id, secret and code.

curl -X POST https://app-emailwarmup.bobwork.ai/api/v1/mailboxes/zoho \
  -H "Authorization: Bearer bwk_YOUR_KEY" -H "Content-Type: application/json" \
  -d '{"email": "you@yourdomain.com", "client_id": "1000.XXX", "client_secret": "XXX", "code": "1000.XXX", "dc": "com"}' 

Everything the API can do

Sign up without a browser

Billing

Account

Connect mailboxes

Mailboxes

Health

Outbound

Domains & mailboxes

Errors return {"error": "…"} with status 400, 401, 402 (out of credits: the body says how to pay; over the free mailbox limit a connect still answers 201 with needs_billing:true), 404, 409 or 429.

Paying: the person clicks once

An agent cannot pay. For extra mailboxes call POST /billing/checkout (monthly, or {"yearly": true}); for Outbound credits call POST /credits/checkout with {"usd": 10}, 25 or 100. Each returns a Stripe Checkout url for the account owner to open. Then poll GET /billing: subscription.active turns true, or credits_usd rises, as soon as Stripe confirms. The same three calls are the MCP tools create_billing_checkout, create_credits_checkout and get_billing_status.

MCP server

The same features as an MCP server, so an AI assistant can connect mailboxes, read warm-up health and run campaigns for you. Remote server, nothing to install. URL: https://app-emailwarmup.bobwork.ai/mcp, transport Streamable HTTP, auth with your API key.

Claude Code

claude mcp add --transport http email-warmup https://app-emailwarmup.bobwork.ai/mcp \
  --header "Authorization: Bearer bwk_YOUR_KEY"

Cursor, Windsurf, VS Code and other clients (mcp.json)

{
  "mcpServers": {
    "email-warmup": {
      "url": "https://app-emailwarmup.bobwork.ai/mcp",
      "headers": { "Authorization": "Bearer bwk_YOUR_KEY" }
    }
  }
}

Claude Desktop (claude_desktop_config.json, through the mcp-remote bridge)

{
  "mcpServers": {
    "email-warmup": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://app-emailwarmup.bobwork.ai/mcp", "--header", "Authorization: Bearer ${EW_KEY}"],
      "env": { "EW_KEY": "bwk_YOUR_KEY" }
    }
  }
}

Then ask things like "connect sales@mydomain.com with this app password", "which of my mailboxes are ready for outbound?" or "why is my spam rate up on hello@?".

MCP tools (39)

Limits and safety

• 120 requests per minute per key, up to 5 keys per account. Keys are stored hashed and can be revoked at any time.
• A key acts as its owner only: it sees and changes only your own mailboxes and campaigns, never anyone else's.
• Removing a mailbox needs an explicit confirm. Starting a campaign sends real email, uses credits and requires accepting the sending rules.
• The API and MCP are free. Warm-up is free up to 10 mailboxes (20 for accounts created before 27 October 2026), then $5 per mailbox per month ($3 each from 10 extra, $2 each from 50 extra)); Outbound emails cost $2 per 1,000 in prepaid credits.

FAQ

Is there a cost to use the API? No. The API and MCP server are free. You only pay for mailboxes above your free mailboxes, or for Outbound emails you choose to send.

Can I connect Outlook / Microsoft 365? Not yet: Microsoft requires OAuth for mailbox access, which is on the roadmap.

Does the API read my real email? No. Warm-up only touches its own warm-up emails. The optional Inbox feature is separate, opt-in, and not part of the API.

Where do I get help? Email info@bobwork.ai or use the Feedback page in the app.