API Reference
Developer API Docs
Free Email Checker API reference – verify emails and look up domain reputation/identity data over REST, with a public OpenAPI 3.0 spec and copy-paste curl examples for every endpoint.
What this API is for
Everything the checker widget on this site does – the 8-signal trust score, disposable/catch-all detection, and domain reputation/identity lookups – is also available as a REST API, so it can be called from a script, a CRM, an automation platform, or an AI agent instead of only through the web form.
Built for real integrations, not just this website
The endpoints below accept and return plain JSON, are described by a standard OpenAPI 3.0 document, and return results synchronously for a single check or as a pollable/webhook-notified job for a batch – the same shape a production integration would expect, whether that integration is a person writing code or an automated agent calling it as a tool.
Frequently Asked Questions
Do I need an API key to read this documentation?
No – this page and the OpenAPI spec it links to are both public. A key is only required to actually call the endpoints.
Is there a machine-readable spec I can import into Postman/an SDK generator/an AI agent?
Yes – the OpenAPI 3.0 JSON spec linked at the top of this page describes every endpoint, parameter, and response shape and can be imported directly.
Is this API free to use?
Every key gets a daily quota set when it is created; there is no separate charge for API access beyond whatever quota the site owner assigns the key.
