Email Verification API: Build Email Intelligence Into Your App
The Postmaster+ Email Verification API gives developers a single REST endpoint to verify email addresses, score engagement likelihood, and enrich contact data — all in real time. Simple authentication, JSON responses, and comprehensive documentation make integration fast.
Quick Start
Get started with the Email Verification API in minutes. Sign up for a free account, grab your API key, and make your first verification call:
Verify an Email Address
curl -X POST "https://postmasterplus.app/api/v1/intelligence/single-emails/scan" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"email": "user@example.com",
"actions": "verification,activity"
}'Retrieve Existing Email Data
curl -X GET "https://postmasterplus.app/api/v1/intelligence/single-emails/user@example.com" \ -H "Authorization: Bearer YOUR_API_KEY"
Blocklist Scan
curl -X POST "https://postmasterplus.app/api/v1/blocklist/scan/start" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"urls": ["https://example.com/track?id=123"]
}'API Capabilities
Email Verification
Validate syntax, DNS, MX records, and mailbox existence. Detect disposable, role-based, and catch-all addresses. Get deliverable/undeliverable/risky status codes.
Engagement Scoring
0–10 activity score predicting engagement likelihood. Based on historical behavioral signals — recency, frequency, and type of activity — not just whether the mailbox exists, but whether anyone reads it.
Data Enrichment
Append postal addresses, full names, company information, and demographic data from email addresses. Enrich your CRM without third-party append services.
Blocklist Scanning
Scan URLs against impactful blocklists with link detonation. Async job processing with status polling for results.
Risk Assessment
Combined risk scoring based on verification result, domain type, address pattern, and historical data. Make accept/reject decisions with a single score.
Batch Processing
Process lists of email addresses efficiently. Ideal for cleaning existing databases and pre-campaign validation.
API Reference
| Endpoint | Method | Description |
|---|---|---|
| /intelligence/single-emails/{email} | GET | Retrieve existing email intelligence data |
| /intelligence/single-emails/scan | POST | Verify, score, and enrich an email address |
| /blocklist/scan/start | POST | Start a blocklist scan |
| /blocklist/scan/status/{id} | GET | Check blocklist scan results |
Base URL
https://postmasterplus.app/api/v1Authentication
Bearer token in Authorization header
Format
JSON request/response with Content-Type: application/json
Common Integration Patterns
Signup Form Validation
Call the verification endpoint when users submit their email on registration forms. Block disposable emails, catch typos in real time, and prevent fake accounts from entering your system. Average API response time makes it suitable for synchronous form validation.
CRM Data Quality
Run batch verification on your CRM database to identify invalid, risky, and disengaged contacts. Use engagement scoring to segment your database and enrich records with postal and demographic data.
Pre-Campaign List Cleaning
Before sending email campaigns, verify your target segment. Remove hard bounces, suppress risky addresses, and prioritize contacts with high engagement scores.
E-commerce Checkout
Verify the customer's email at checkout to ensure order confirmations, shipping notifications, and receipts will be delivered. Flag suspicious addresses to reduce fraud.
Lead Scoring Enhancement
Combine verification status and engagement scores with your existing lead scoring model. A verified email with a high activity score is a better lead than an unverified one.
Content Link Safety
Use the Blocklist API to scan all links in your email content before sending. A single blocklisted URL in your email can cause the entire campaign to be filtered to spam.
API Pricing
The Email Verification API uses a credit-based pricing model. All API calls — verification, engagement scoring, data enrichment, and blocklist scanning — draw from the same credit pool.
Starting at
$0.01
per credit
Volume pricing
$0.005
per credit at scale
Credits valid for
12
months from purchase
Developer Resources
API Documentation
Complete endpoint reference with request/response examples.
OpenAPI Specification
Machine-readable API spec for code generation and testing.
Postman Collection
Pre-built collection for testing API endpoints in Postman.
Partner Program
Integrate Postmaster+ into your platform with our partner API.