Email Validator API

3-stage email validation: syntax check, MX record lookup, optional SMTP mailbox verification.

Endpoints

GET /validate?email=user@example.com&smtp=false

Parameters:

• email (required): Email address to validate
• smtp (optional, default false): Perform SMTP mailbox verification (slower, ~10s)

Example:

curl "https://your-app.onrender.com/validate?email=test@gmail.com"

Response:

{
  "email": "test@gmail.com",
  "valid": true,
  "stage": "mx",
  "syntax": {"valid": true, "local": "test", "domain": "gmail.com"},
  "mx": {
    "has_mx": true,
    "records": [{"priority": 5, "exchange": "gmail-smtp-in.l.google.com"}, ...],
    "best": "gmail-smtp-in.l.google.com"
  },
  "smtp": null,
  "fetched_at": "2026-07-14T14:54:51.343966+00:00"
}

Stages

Stage	What it checks	Fails on
syntax	RFC 5322 format	Bad format, too long
mx	DNS MX records for domain	Domain can't receive mail
smtp	SMTP RCPT TO command	Mailbox doesn't exist (optional)

GET /health

Returns {"status": "ok"}.

Local development

python -m venv .venv
.venv\Scripts\activate
pip install -r requirements.txt
uvicorn app.main:app --reload --port 8125

Available on RapidAPI

Live API: https://rapidapi.com/On13uka/api/email-validator112

Subscribe and get instant API key. Free tier: 100 requests/month.

Other APIs in the Portfolio

• Domain WHOIS
• Company Info
• Email Validator
• IP Geolocation
• Sanctions Screener

All APIs available on RapidAPI: https://rapidapi.com/user/On13uka