What is IsTempMail?

IsTempMail is a lightweight JSON API that detects and blocks disposable email addresses in real time. By checking an email against a database of over 124,000 known temporary email domains, it helps you prevent spam, fake registrations, and free trial abuse before they happen. The service offers a single endpoint that returns a clear, human-readable JSON response, making integration straightforward for any developer.

Who it's for

• SaaS founders who want to reduce fake signups and protect their trial revenue from abuse.
• WordPress site owners who need a plug-and-play solution to block disposable email registrations without writing code.
• Developers who require a simple, reliable API to validate email addresses at the point of entry in their applications.

Key features

Single endpoint, simple JSON response

IsTempMail keeps things minimal. You POST an email address or domain to one endpoint, and get back a JSON object with the domain name, a blocked boolean, and an optional unresolvable flag. No complex setup, no multiple endpoints — just a clean validation result you can parse in any language.

Always up-to-date block list

New disposable email providers appear daily, and IsTempMail adds between 5 and 20 new domains to its block list every day. The database currently holds over 124,000 domains, and the team actively monitors for new temporary email services so your validation stays effective.

WordPress plugin and API libraries

For WordPress users, a free plugin lets you block disposable emails with just a few clicks — sign up, enter your API token, and you're done. Developers can also use the official JavaScript (npm) and PHP (GitHub) libraries to integrate the API faster into custom projects.

What stands out

"Simple works best. We have one endpoint for all functionality and give you an easy to parse and human understandable JSON response."

IsTempMail was built by a software engineer who values clarity over complexity. Instead of juggling multiple endpoints or deciphering cryptic error codes, you get a straightforward blocked: true/false response. This developer-first approach, combined with a free tier of 200 requests per month and paid plans starting at $5/month for 5,000 requests, makes it accessible for projects of any size.

Worth checking out if…

You run a signup flow, a WordPress site, or any online service where disposable email addresses cause spam, fake accounts, or trial abuse. IsTempMail's minimal API, generous free tier, and affordable paid plans make it a practical choice for teams that want reliable disposable email detection without unnecessary overhead.