REST API

Verify Emails in Real-Time

Integrate email verification directly into your sign-up flows, CRMs, and applications. Stop bad emails before they enter your database.

Free tier includes 100 verifications

verify.json
{
  "email": "user@company.com",
  "status": "valid",
  "score": 98,
  "checks": {
    "syntax": true,
    "mx_records": true,
    "smtp_check": true,
    "disposable": false,
    "role_based": false
  },
  "reason": "deliverable"
}
~200ms
Response Time
99.99%
Uptime SLA
100+
Requests/Sec
10M+
Daily Checks
Unmatched Accuracy

The World's Most Accurate Verifier API

Identify over 30+ email types in real-time. Protect your sender reputation by blocking bad emails at the source.

Valid Emails

  • • Genuine addresses
  • • Verified MX records
  • • Accept-all domains
  • • AI Scored confidence

Invalid Emails

  • • Syntax errors & Typos
  • • No DNS entries
  • • Unroutable IPs
  • • Mailbox doesn't exist

Threat & Risks

  • • Spam traps & Honeypots
  • • Disposable / Temporary
  • • Toxic & Abuse domains
  • • Role-based (admin@, sales@)

Integrate Where It Matters

See how SendSure fits into your workflow at every touchpoint.

User Enters Email
SendSure API~200ms
Validated
Rejected

Real-Time Form Validation

Validate emails the moment users enter them. Instant feedback improves UX and prevents bad data from ever reaching your database.

Signup FormsCheckoutLead Gen
  • Average 200ms response time
  • Block fake signups at the source
  • Suggest fixes for typos

Common Integration Points

Developers use SendSure's API across their entire stack

User Registration

Validate emails during signup before sending confirmation emails.

CRM Import

Clean contact lists on import to keep your CRM data pristine.

E-commerce Checkout

Verify customer emails before order confirmation to prevent delivery issues.

Marketing Automation

Validate leads before adding to drip campaigns for better deliverability.

Seamless Integration with Popular Platforms

Take advantage of our email validation API with ease by connecting directly to your favorite tools.

HubSpotMailchimpSalesforceZapierMakeActiveCampaign
Integrate

Simple, Powerful Integration

Start verifying emails with a single API call. Standard HTTP methods and descriptive JSON responses.

const SendSure = require('sendsure');
const client = new SendSure('YOUR_API_KEY');

// Verify a single email
const result = await client.verify('user@example.com');

if (result.status === 'valid') {
  console.log('Email is deliverable!');
  console.log(`Confidence: ${result.score}%`);
} else {
  console.log(`Rejected: ${result.reason}`);
}
How It Works

API Service at a Glance

Deploys instantly across your stack to block bad signups, clean incoming leads, and preserve your sender reputation.

Validate Instantly

Intercept invalid addresses in milliseconds at registration, checkout, or CRM import.

  • Blocks disposables & role-based
  • Real-time typo correction

Complete SDKs

Integrate easily with native libraries for Node.js, Python, PHP, Ruby, Java, Go, and more.

NodePythonPHPGo

Geo-Redundant

Deployed globally with smart latency-based routing to ensure requests hit the closest server.

  • 99.99% Uptime SLA
  • ~200ms average response

99% Accuracy

Guaranteed precision

Real-Time

<200ms form checks

Rapid Scale

Auto-scaling infrastructure

Secure

256-bit TLS encryption

Frequently Asked Questions

Common questions about the SendSure API

What does the API response include?

Each response includes status (valid, invalid, risky, unknown), a confidence score (0–100), reason codes, and flags for disposable addresses, role-based emails, catch-all domains, and more.

What are the rate limits?

The API supports 100+ concurrent requests per second. For higher volumes, our batch endpoint can process up to 1,000 emails per call with webhook callbacks for results.

Do you offer sandbox/test mode?

Yes! Use test API keys to verify against our sandbox without consuming credits. The sandbox returns realistic responses for testing your integration.

How do I handle errors?

The API returns standard HTTP status codes with descriptive JSON error bodies. Our SDKs include built-in retry logic with exponential backoff for transient failures.

Is the API GDPR compliant?

Absolutely. All data is encrypted in transit and at rest. We do not store email addresses beyond the verification request. We are SOC 2 Type II certified.

Integrate the Ultimate Verification Engine

Robust RESTful architecture, webhook events, and deep SDK support to embed SendSure seamlessly into your stack.