Developer API

Infrastructure as Code for Cold Email

Provision domains, mailboxes, DNS, and sequencer connections in a single API call. Built for AI-native agencies that onboard clients in minutes, not days.

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One Call, Full Stack

Buy 10 domains with 30 mailboxes, configure personas, set forwarding URLs, and connect to your client's sequencer — one POST request. We handle registration, Google Workspace / M365 provisioning, DNS, DKIM, and DMARC.

Bring Your Own Domains

Client already has domains? Import them from any registrar. Stage them, checkout, then choose your DNS setup — point nameservers to us, connect via Cloudflare API, or request done-for-you setup.

Any Sequencer, Any Client

Instantly, Smartlead, EmailBison, PlusVibe, or your client's custom platform. Connect and swap integrations via API. Mailboxes sync automatically — no manual CSV exports.

Onboard a new client in one API call

Register a domain, provision 3 Google Workspace mailboxes with custom personas, and auto-connect to your sequencer. One request, fully automated.

Charges your default payment method. We handle domain registration, workspace creation, DNS records, DKIM, DMARC, forwarding — everything. Get webhook notifications when each mailbox is live and ready to send.

See full endpoint docs

bash

curl -X POST https://api.cheapinboxes.com/v1/orders/checkout \
  -H "Authorization: Bearer ci_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "domains": [
      {
        "domain": "acmeoutreach.shop",
        "mailboxes": {
          "provider": "google",
          "accounts": [
            {
              "first_name": "Emma",
              "last_name": "Johnson",
              "email_prefix": "emma.johnson",
              "profile_picture_url": "https://example.com/emma.jpg",
              "tags": ["SDR", "US-West"]
            },
            {
              "first_name": "Sarah",
              "last_name": "Wilson",
              "email_prefix": "sarah.wilson"
            },
            {
              "first_name": "Olivia",
              "last_name": "Davis",
              "email_prefix": "olivia.davis"
            }
          ]
        }
      }
    ],
    "integration_id": "your-bison-integration-id",
    "promo_code": "LAUNCH20"
  }'

json

{
  "event": "mailbox.credentials_ready",
  "timestamp": "2026-03-30T14:22:00Z",
  "data": {
    "mailbox_id": "mb_abc123",
    "email": "emma.johnson@acmeoutreach.shop",
    "domain": "acmeoutreach.shop",
    "provider": "google",
    "status": "active"
  }
}

domain.provisionedDNS is configured, domain is live

mailbox.activeMailbox created and provisioned

mailbox.credentials_readyLogin credentials available

order.completedAll domains & mailboxes in an order are done

billing.invoice_paidRecurring invoice charged successfully

Know the moment it's ready

Subscribe to webhook events and get notified instantly when domains provision, mailboxes go active, or credentials are ready. Signed payloads, delivery logs, automatic retries.

Set up webhooks from the dashboard or via API. Choose exactly which events matter to your workflow — no noise.

MCP Compatible

Give your AI agent an API key

Cheap Inboxes works as an MCP server. Let your AI agent provision infrastructure, manage DNS, and swap sequencers without human intervention. The same API your code calls, your agent calls.

Give your agent access in 1 click

Add to Cursor

Cursor config (.cursor/mcp.json)

{
  "cheapinboxes": {
    "url": "https://api.cheapinboxes.com/mcp",
    "headers": {
      "Authorization": "Bearer YOUR_API_KEY"
    }
  }
}

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "cheapinboxes": {
      "url": "https://api.cheapinboxes.com/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

Claude Code CLI

claude mcp add cheapinboxes \
  --transport http \
  --url https://api.cheapinboxes.com/mcp \
  --header "Authorization: Bearer YOUR_API_KEY"

Everything you need, one API

70+ endpoints covering the full lifecycle — from domain search to mailbox deprovisioning.

Domain registration & import

Mailbox provisioning (Google & M365)

DNS, DKIM, DMARC management

Sequencer connect & sync

Webhooks with signed payloads

Billing, invoices & payments

Ready to automate your infrastructure?

Get an API key in 30 seconds. Start provisioning domains and mailboxes programmatically.

Read the Docs Get an API Key