email APIs

Mailjet lets you send transactional and marketing emails via a simple REST API using MJML or HTML templates.

Tomba is an email finding and verification service geared toward B2B sales outreach, letting you look up professional email addresses by name and company domain or verify whether an email address is deliverable.

Smarty's US Extract API scans any block of unstructured text — emails, documents, web pages — and extracts all US postal addresses it finds, then validates each one against USPS data for deliverability.

Hunter (hunter.io) provides APIs to find and verify professional email addresses associated with any domain, making it a go-to tool for sales prospecting and lead enrichment.

mailboxlayer is an email validation API that checks whether an email address is syntactically correct, has a valid MX record, and is not a disposable address.

Cloudmersive Validate is a comprehensive validation API that can verify email addresses, phone numbers, VAT numbers, and domain names in a single platform.

Disify is a free, no-auth API that checks whether an email address or domain belongs to a known disposable or temporary email service.

DropMail provides a GraphQL API for creating and managing temporary email inboxes, letting you generate disposable addresses and receive real emails without registration.

Abstract API Email Validation checks whether an email address is deliverable, properly formatted, and not from a disposable or spam-trap domain.

Guerrilla Mail provides a REST API for creating and reading disposable temporary email addresses, useful for testing email flows without exposing real inboxes.

ImprovMX is an email forwarding service with a REST API that lets you programmatically manage domains and forwarding rules — mapping email aliases to real destination addresses.

Kickbox provides a free, no-auth email verification endpoint that checks whether an email address is deliverable by performing syntax validation, domain MX lookup, and disposable address detection.

mail.gw is a REST API for creating and managing temporary 10-minute email addresses with full inbox access, all without authentication for basic use.

mail.tm is a temporary email service API that creates persistent (but disposable) email accounts accessible via a REST interface using JWT authentication.

MailboxValidator performs multi-layered email address validation including syntax checking, DNS/MX record lookup, disposable email detection, and SMTP mailbox verification to help improve email list deliverability.

MailCheck.ai (powered by UserCheck) is a free API that detects whether an email domain belongs to a known temporary or disposable email provider, helping prevent fake sign-ups without requiring authentication.

SendGrid (now part of Twilio) is an industry-standard cloud email API for sending transactional and marketing emails at scale, with support for SMTP relay and REST API delivery.

EmailRep is a free API that evaluates the risk and reputation of an email address in seconds.

Mailsac lets you create disposable email addresses and read incoming messages via API — ideal for testing email-sending features in your app.