Welcome to the Cold Mail Reseller API
Build a fully white-labeled cold email platform without managing email infrastructure yourself.The Cold Mail Reseller API lets you provision domains, create mailboxes, manage subscriptions, automate warmup, and export credentials to sending platforms.Your customers interact only with your platform while CMR handles domain registration, mailbox provisioning, and deliverability behind the scenes.Whether you're building a lead generation platform, a cold outreach tool, an agency dashboard, or an email SaaS, the API gives you what you need to launch and scale reliable sending infrastructure.
Start Building#
Quick Start
Build your first integration end-to-end in one worked example.
Authentication
Generate an API key and authenticate every request.
Overview
How the API works and how resources are connected.
Core Resources#
Users
Create and manage the customers on your platform.
Domains
Register, renew, and manage domains.
Mailboxes
Provision and manage business mailboxes.
DNS Management
Configure SPF, DKIM, and DMARC records.
Subscriptions
Manage billing, renewals, and cancellations.
Pre-Warmup
Order mailboxes that are already warmed and ready to send.
Mailbox Warmup
Automate sender reputation building for new mailboxes.
Domain Renewal
Handle renewals, grace periods, and expiration.
1+ Year Subscriptions
Pricing changes once a subscription crosses 12 months.
Platform Exports
Push SMTP credentials to a supported sending platform.
OAuth Exports
Connect a mailbox to Google or Microsoft directly.
Sandbox API
Test order flows without real charges.
Event-Driven Integrations#
Every async operation — orders, renewals, warmup, exports — reports completion through a webhook rather than the original request. Start with Webhooks Overview for delivery, retries, and signature verification, then use the event-specific pages below for exact payload shapes.
Webhooks Overview
Delivery, retries, and signature verification.
Domain Events
Domain registration and renewal events.
Mailbox Events
Mailbox creation and update events.
Subscription Events
Renewal, past-due, and cancellation events.
Prewarmup Events
Pre-warmup order assignment events.
Mailbox Warmup Events
Warmup start and removal events.
Developer Resources#
Errors
Status codes, error messages, and retry strategy.
Rate Limits
Request limits and how to handle 429 responses.
Pagination
page and limit query params on list endpoints. Modified at 2026-08-06 06:22:18