Free APIs
Free Email & messaging APIs
| API | Free tier | Auth | Docs |
|---|---|---|---|
| Abstract Email Validation Validate email syntax, MX records and disposable domains Catch: Free plan has a small monthly quota | Free plan with monthly request allowance | API key | docs |
| Hunter Email Verifier Find and verify email addresses Catch: Credits shared between search and verification | Free plan: 50 free leads/month | API key | docs |
| ZeroBounce Email validation and deliverability scoring Catch: Small monthly allowance; API key required | Free monthly validation credits | API key | docs |
| mailboxlayer Email address validation API Catch: Non-commercial use | Free plan: 100 API requests/month | API key | docs |
| Numverify Phone number validation and carrier lookup Catch: Paid plans from $14.99/month | Free: 100 phone validations/month | API key | docs |
| Resend Developer email sending API Catch: Free plan has daily sending limits and one domain | Free plan available | API key | docs |
| Brevo (Sendinblue) Transactional and marketing email, SMS API Catch: Brevo branding on free-plan emails | Free plan: up to 300 emails/day | API key | docs |
| MailerSend Transactional email API Catch: Free plan: limited domains and support | Free plan: 3,000 emails/month | API key | docs |
| Mailjet Email sending API Catch: Mailjet branding on free-plan emails | Free plan: 6,000 emails/month, 200/day | API key | docs |
| Telegram Bot API Build bots that send and receive Telegram messages Catch: Bot token from BotFather; flood limits apply | Free | API key | docs |
FAQ
What is the best free email & messaging API?+
Abstract Email Validation, Hunter Email Verifier, ZeroBounce are good places to start. Compare the free tiers and catches in the table; they differ mostly in limits and whether commercial use is allowed.
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