API Documentation

Learn how to integrate SendSure email verification into your application. Our RESTful API makes it easy to verify emails in real-time or process large batches.

Authentication

All API requests require authentication using your API key. Include your API key in the Authorization header as a Bearer token.

HTTP Header

Authorization: Bearer YOUR_API_KEY

💡 Tip: You can find your API key in your Dashboard under Settings → API Keys.

Quick Start

Here's a quick example to verify an email address using cURL:

cURL

curl -X POST https://api.sendsure.co/v1/verify/single \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"email": "user@example.com"}'

Verify Single Email

Verify a single email address in real-time. This endpoint returns results immediately.

POST /v1/verify/single

Request Body

Parameter	Type	Required	Description
`email`	string	Yes	The email address to verify

Example Response

JSON

{
  "email": "user@example.com",
  "status": "VALID",
  "result": "valid",
  "score": 95,
  "reason": "Mailbox exists and accepts mail",
  "flags": ["has_mx", "has_spf", "has_dmarc"],
  "metadata": {
    "firstName": "User",
    "lastName": null,
    "domain": "example.com",
    "provider": "google_workspace",
    "verificationTime": 342
  }
}

Verify Batch

Submit a batch of emails for verification. This initiates an async process. Use the returned batchId to check status.

POST /v1/verify/batch

Request Body

Parameter	Type	Required	Description
`emails`	array	Yes	Array of email addresses to verify (max 10,000)
`webhookUrl`	string	No	URL to receive results when processing completes

Response Fields

Every verification response includes these fields:

Field	Type	Description
`status`	string	VALID, INVALID, RISKY, UNKNOWN, or ACCEPT_ALL
`result`	string	Simplified result: valid, invalid, risky, unknown
`score`	integer	Quality score from 0-100 (higher is better)
`flags`	array	Array of detection flags (disposable, role, spam_trap, etc.)
`reason`	string	Human-readable explanation of the result

Rate Limits

API requests are rate-limited to ensure fair usage:

Plan	Rate Limit
Free	10 requests/minute
Paid	100 requests/second
Enterprise	Custom limits available

⚠️ Note: Exceeding rate limits returns a 429 status code. Implement exponential backoff in your integration.