Build an Email Validation System with a Free API — Disposable Detection, MX Checks, Typo Suggestions

#api #webdev #python #email

Bad email addresses cost money. Every bounced email hurts your sender reputation, and disposable emails pollute your user database. Most email validation services charge $0.005–$0.01 per check — that's $50 for 10,000 validations.

I built a free Email Validation API that handles the heavy lifting: syntax validation, MX record verification, disposable domain detection (500+ domains), and even typo suggestions (catches gmial.com → gmail.com).

What It Checks

Syntax validation — RFC-compliant format check
MX record lookup — Does the domain actually accept email?
Disposable detection — 500+ throwaway email providers flagged
Typo correction — Suggests fixes for common domain typos
Role-based detection — Flags info@, admin@, support@ addresses

Quick Start

curl "https://email-validation-api.p.rapidapi.com/validate?email=user@gmial.com"

Response:

{
  "email": "user@gmial.com",
  "valid_syntax": true,
  "mx_records": false,
  "is_disposable": false,
  "is_role_based": false,
  "suggestion": "user@gmail.com",
  "score": 30,
  "verdict": "risky"
}

Notice it caught the gmial.com typo and suggested gmail.com.

JavaScript — Form Validation

async function validateEmail(email) {
  const response = await fetch(
    `https://email-validation-api.p.rapidapi.com/validate?email=${encodeURIComponent(email)}`
  );
  const result = await response.json();

  if (result.is_disposable) {
    return { valid: false, reason: 'Disposable emails are not allowed' };
  }

  if (result.suggestion) {
    return { valid: false, reason: `Did you mean ${result.suggestion}?` };
  }

  if (result.score < 50) {
    return { valid: false, reason: 'This email address appears invalid' };
  }

  return { valid: true };
}

// Usage in a signup form
const { valid, reason } = await validateEmail('user@gmial.com');
if (!valid) {
  showError(reason); // "Did you mean user@gmail.com?"
}

Python — Bulk Validation

import requests
import csv

def validate_email(email: str) -> dict:
    response = requests.get(
        "https://email-validation-api.p.rapidapi.com/validate",
        params={"email": email},
        timeout=10
    )
    return response.json()

# Validate a CSV of emails
with open("emails.csv") as f:
    reader = csv.DictReader(f)
    for row in reader:
        result = validate_email(row["email"])
        if result["is_disposable"]:
            print(f"DISPOSABLE: {row['email']}")
        elif result["score"] < 50:
            print(f"INVALID: {row['email']} (score: {result['score']})")
        elif result.get("suggestion"):
            print(f"TYPO: {row['email']} → {result['suggestion']}")
        else:
            print(f"OK: {row['email']}")

When to Use This

Scenario	Without validation	With validation
Signup form	15% fake emails → bounce	Catch typos + disposables at entry
Newsletter	High bounce rate → domain blacklisted	Only valid addresses get through
Lead gen	Sales wastes time on bad leads	Only real emails in CRM
Waitlist	Inflated numbers, useless data	Accurate user count

API Response Fields

Field	Type	Description
`valid_syntax`	boolean	RFC email format check
`mx_records`	boolean	Domain has MX records
`is_disposable`	boolean	Known throwaway provider
`is_role_based`	boolean	Generic address (info@, admin@)
`suggestion`	string	Typo correction (null if none)
`score`	number	0–100 deliverability score
`verdict`	string	`valid`, `risky`, or `invalid`