Developers

API access

Run warmup from your own stack. The Warmup Inbox REST API covers the full inbox lifecycle: create and connect inboxes, start and pause warmup, pull placement metrics, and manage templates, tags, and plans.

Read the API docs Start 7-day free trial

JSON over HTTPS
API key auth
120 requests/min

Example request

$ curl https://api.warmupinbox.com/v1/inboxes \
    -H "x-api-key: YOUR_API_KEY"

200 OK

{
  "items": [
    {
      "inbox_id": "inbox_GM5i7HCSJ9bMN10O",
      "status": "running",
      "type": "google",
      "email": "outreach@yourdomain.com",
      "score": 98
    }
  ]
}

API surface

Manage the full warmup lifecycle over REST

Everything below ships today in v1, documented endpoint by endpoint with request parameters, response schemas, and error codes.

Inbox lifecycle

Create inboxes, update their settings, start and pause warmup, and delete inboxes when a campaign winds down.

POST/v1/inboxes

Any provider, SMTP/IMAP included

Connect Google and Microsoft accounts via OAuth, or any custom mailbox with advanced SMTP and IMAP settings.

POST/v1/inboxes/advanced

Placement metrics

Pull inbox, spam, and category placement plus replies for any timeframe, per inbox. Pipe scores into your own reporting.

GET/v1/inboxes/{id}/metrics

Templates and topics

Create custom warmup templates and set AI-generated email topics on Pro and Max plans.

POST/v1/email-templates

Plans and credits

Move an inbox between Basic, Pro, and Max, and check the remaining credits on your account.

PATCH/v1/inboxes/{id}/plan

Getting started

Three steps to your first call

Create an account

Start with the 7-day free trial or any paid plan, then generate your API key inside the Warmup Inbox app.

Authenticate

Send your key in the x-api-key header. Every endpoint lives under api.warmupinbox.com/v1 and returns JSON.

Build and ship

Work from the interactive reference or import the Postman collection with ready-made requests and code snippets for Node.js, Python, and more.

Who builds on it

Built for teams that automate warmup

Agencies

Spin up warmup the moment a client hands you a new domain. Tag inboxes per client and feed placement metrics straight into your reporting.

SDR teams

Wire warmup into the rest of your sales stack. Pause inboxes while sequences ramp, restart them between campaigns, and watch scores from your own dashboards.

Integration partners

Offer warmup inside your own product, backed by a network of 30,000+ real inboxes. Talk to us about partner access.

Ready when you are

Warm up inboxes from your own stack

Generate an API key, make your first call in minutes, and let 30,000+ real inboxes handle the engagement that gets you to 98%+ inbox placement.

Start 7-day free trial Read the API docs

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FAQ

Frequently asked questions

How do I get an API key?

Create a Warmup Inbox account (the 7-day free trial works) and generate a key inside the app. You then send it with every request in the x-api-key header.

What can I do with the API?

The full inbox lifecycle: create, update, start, pause, and delete inboxes, connect mailboxes over SMTP/IMAP or OAuth, pull placement metrics for any timeframe, manage templates, topics, and tags, switch plans per inbox, and check your account credits.

What are the rate limits?

120 requests per minute. Requests beyond the limit are temporarily blocked until it resets, so build retry logic with backoff into your client.

Which API features depend on my plan?

Reply rate caps scale with your plan: up to 25% on Basic, 45% on Pro, and 65% on Max. Email topics, custom templates, and per-inbox sending schedules with timezone control are available on Pro and Max.

Is there a Postman collection?

Yes. It covers every endpoint with pre-configured requests and code snippets for Node.js, Python, and more. The reference is also available as machine-readable JSON for tooling that consumes OpenAPI documents.

Can I connect custom mailboxes through the API?

Yes. The advanced inbox endpoint accepts SMTP and IMAP settings (host, port, TLS) plus Google and Microsoft OAuth configs, so any mailbox you can warm in the dashboard you can also connect over the API.