Email APIs

Creates disposable inboxes and returns incoming messages as JSON, authenticating with a session cookie rather than a key. Guerrilla Mail enforces a rate limit but does not publish the exact number.

Validates email addresses, phone numbers, street addresses, VAT numbers and domains in one REST service. The free plan includes 600 calls per month that never expire, but needs an API key.

Issues disposable inboxes through GraphQL and pushes new mail over websocket or long polling instead of forced refreshing. A free token is handed out automatically, no account signup required.

Creates throwaway inboxes for signup confirmations and testing with no signup or key of its own. Requests are capped at 8 per second per IP address, and the service costs nothing to use.

Checks format, MX records and live SMTP deliverability, and flags disposable or catch all addresses. The free plan allows 100 requests a month with no credit card needed to start.

Checks email syntax, MX records, and disposable or privacy relay domains, including plus alias tricks people use to dodge signup limits. Core checks need no signup or API key at all.

Manages custom domain email forwarding and aliases, letting incoming mail route to another inbox. Needs an API key sent as HTTP basic auth, and the free plan is capped at 30 requests per minute.

Checks email syntax, SMTP reachability, and catch all or disposable status to gauge deliverability. The free plan covers 100 requests monthly, sometimes 1000 during a signup promotion, with a key.

Spins up throwaway inboxes so test scripts can complete signup flows that demand email confirmation. No account or API key is needed, though requests are capped at 8 per second per IP.

Rebranded from MailCheck.ai to UserCheck, this service flags disposable, forwarding and typo prone email addresses before signup. Free tier gives 1000 credits monthly at one request per second.

Confirms whether an address belongs to a free email provider versus a business domain, returning JSON or XML. Requires an API key from any MailboxValidator plan, including the free one.

Flags disposable, role based and free provider addresses for signup forms, run by the same team behind Kickbox's paid verification service. No API key is required and anonymous use is allowed.

Sendinblue was renamed Brevo in 2023; the unified REST API now sends email, SMS and WhatsApp messages and manages contacts and ecommerce data. An API key is required for every request.

Twilio owns SendGrid now, and this REST API sends transactional and marketing email at scale while tracking stats and managing contact lists. Every call needs an API key for authentication.

Catches test emails in a sandbox inbox before they reach real recipients, and the same platform sends production email through a token authenticated API. Free plan allows 4000 emails monthly.