mikkelscheike
Email Provider Links
🔒 Modern email provider detection library with enhanced TypeScript support and enterprise security
A robust TypeScript library providing direct links to 93 email providers (180 domains) with concurrent DNS resolution, optimized performance, comprehensive email validation, and advanced security features for login and password reset flows.
🚀 Try it out
Live Demo - Test the library with any email address and see it in action!
✨ New in Version 3.0.0
- 🚀 Performance Optimizations: Further improved DNS resolution and caching
- 🎯 Enhanced Precision: Adjusted performance thresholds based on real-world metrics
- 🛡️ Security Updates: Removed legacy detection methods and updated security hashes
- 📝 TypeScript Improvements: Resolved TypeScript errors and enhanced type safety
- 📚 Documentation: Consolidated and improved documentation for better clarity
- ⚡ Infrastructure: Optimized build process and development workflow
- 🧪 Testing: Expanded test coverage to 445 comprehensive tests
- 🔄 Provider Updates: Added support for 23 new email providers
- 🔍 Advanced Alias Detection: Refined provider-specific email alias handling for dots, plus addressing, and case sensitivity
✨ Core Features
- 🚀 Fast & Lightweight: Zero dependencies, ultra-low memory (0.10MB initial, 0.00004MB per 1000 ops), small footprint (~39.5KB compressed)
- 📧 93 Email Providers: Gmail, Outlook, Yahoo, ProtonMail, iCloud, and many more
- 🌐 207 Domains Supported: Comprehensive international coverage
- 🌍 Full IDN Support: International domain names with RFC compliance and Punycode
- ✅ Advanced Email Validation: International email validation with detailed error reporting
- 🏢 Business Domain Detection: DNS-based detection for custom domains (Google Workspace, Microsoft 365, etc.)
- 🔒 Enterprise Security: Multi-layer protection against malicious URLs and supply chain attacks
- 🛡️ URL Validation: HTTPS-only enforcement with domain allowlisting
- 🔐 Integrity Verification: Cryptographic hash verification for data integrity
- 📝 Type Safe: Full TypeScript support with comprehensive interfaces
- ⚡ Performance Optimized: Smart DNS fallback with configurable timeouts
- 🚦 Rate Limiting: Built-in DNS query rate limiting to prevent abuse
- 🔄 Email Alias Detection: Normalize Gmail dots, plus addressing, and provider-specific aliases
- 🛡️ Fraud Prevention: Detect duplicate accounts through email alias manipulation
- 📦 Batch Processing: Efficiently process multiple emails with deduplication
- 🧪 Thoroughly Tested: 445 tests with 94.65% code coverage
Installation
Using npm:
npm install @mikkelscheike/email-provider-linksRequirements
- Node.js:
>=18.0.0(Tested on 18.x, 20.x, 22.x, 24.x) - TypeScript:
>=4.0.0(optional, but recommended) - Zero runtime dependencies - No external packages required
Node.js 24 Support ✨
Fully compatible with the latest Node.js 24.x! The library is tested on:
- Node.js 18.x (LTS)
- Node.js 20.x (LTS)
- Node.js 22.x (Current)
- Node.js 24.x (Latest) - Full support with latest features
Supported Providers
📊 Current Coverage: 93 providers supporting 207 domains
Consumer Email Providers:
- Gmail (2 domains): gmail.com, googlemail.com
- Microsoft Outlook (15 domains): outlook.com, hotmail.com, live.com, msn.com, and 11 more
- Yahoo Mail (19 domains): yahoo.com, yahoo.co.uk, yahoo.fr, ymail.com, rocketmail.com, and 14 more
- ProtonMail (4 domains): proton.me, protonmail.com, protonmail.ch, pm.me
- iCloud Mail (3 domains): icloud.com, me.com, mac.com
- Tutanota (6 domains): tutanota.com, tutanota.de, tutamail.com, tuta.io, keemail.me, tuta.com
- SimpleLogin (10 domains): simplelogin.io, 8alias.com, aleeas.com, slmail.me, and 6 more
- FastMail, Zoho Mail, AOL Mail, GMX, Web.de, Mail.ru, QQ Mail, NetEase, Yandex, and many more
Business Email (via DNS detection):
- Microsoft 365 (Business domains via MX/TXT records)
- Google Workspace (Custom domains via DNS patterns)
- Amazon WorkMail (AWS email infrastructure via awsapps.com patterns)
- Zoho Workplace, FastMail Business, GoDaddy Email, Bluehost Email
- ProtonMail Business, Rackspace Email, IONOS, and others
Security & Privacy Focused:
- ProtonMail, Tutanota, Hushmail, CounterMail, Posteo
- Mailfence, SimpleLogin, AnonAddy
International Providers:
- Europe: GMX, Web.de, Orange, Free.fr, T-Online, Libero, Virgilio, Telekom, Tiscali, Skynet, Telenet, Xs4All, Planet.nl, Bluewin, Eircom
- Asia: QQ Mail, NetEase, Sina Mail, Alibaba Mail, Rakuten, Nifty, Naver (Korea), Daum (Korea), Biglobe (Japan), Sify, IndiatTimes (India)
- Eastern Europe: Centrum (Czech/Slovak), Interia, Onet (Poland), Rambler (Russia)
- Other Regions: UOL, Terra (Brazil), Telkom (South Africa), Xtra (New Zealand)
API Reference
Core Functions
getEmailProvider(email, timeout?)
Recommended - Complete provider detection with business domain support.
// Known providers (instant response)
const result1 = await getEmailProvider('user@gmail.com');
// Returns: { provider: "Gmail", loginUrl: "https://mail.google.com/mail/" }
// Business domains (DNS lookup with timeout)
const result2 = await getEmailProvider('user@company.com', 2000);
// Returns: { provider: "Google Workspace", detectionMethod: "mx_record" }getEmailProviderSync(email)
Fast - Instant checks for known providers (no DNS lookup).
const result = getEmailProviderSync('user@outlook.com');
// Returns: { provider: "Outlook", loginUrl: "https://outlook.live.com/" }Email Alias Support
The library handles provider-specific email alias rules:
// Gmail ignores dots and plus addressing
emailsMatch('user.name+work@gmail.com', 'username@gmail.com') // true
// Outlook preserves dots but ignores plus addressing
emailsMatch('user.name+work@outlook.com', 'username@outlook.com') // false
// Normalize emails to canonical form
const canonical = normalizeEmail('u.s.e.r+tag@gmail.com');
console.log(canonical); // 'user@gmail.com'Provider Rules Overview:
- Gmail: Ignores dots, supports plus addressing
- Outlook: Preserves dots, supports plus addressing
- Yahoo: Preserves dots, supports plus addressing
- ProtonMail: Preserves dots, supports plus addressing
- FastMail: Preserves dots, supports plus addressing
- AOL: Preserves everything except case
Real-World Example
async function handlePasswordReset(email: string) {
// Validate email first
const validation = validateEmailAddress(email);
if (!validation.isValid) {
throw new Error(`Invalid email: ${validation.error?.message}`);
}
// Get provider information
const result = await getEmailProvider(validation.normalizedEmail);
return {
providerUrl: result.loginUrl,
providerName: result.provider?.companyProvider || null,
isSupported: result.provider !== null,
detectionMethod: result.detectionMethod
};
}Configuration
// Custom DNS timeout (default: 5000ms)
const result = await getEmailProvider(email, 2000);
// Rate limiting configuration
import { Config } from '@mikkelscheike/email-provider-links';
console.log('Max requests:', Config.MAX_DNS_REQUESTS_PER_MINUTE); // 10
console.log('Default timeout:', Config.DEFAULT_DNS_TIMEOUT); // 5000msAdvanced Usage
<summary>📚 Advanced Features & Specialized Use Cases</summary>
Library Statistics
import { getLibraryStats, getSupportedProviders } from '@mikkelscheike/email-provider-links';
const stats = getLibraryStats();
console.log(`Version ${stats.version} supports ${stats.providerCount} providers`);
const providers = getSupportedProviders();
console.log(`Total providers: ${providers.length}`);Email Alias Detection & Normalization
import {
normalizeEmail,
emailsMatch
} from '@mikkelscheike/email-provider-links';
// Prevent duplicate accounts
async function registerUser(email: string) {
const canonical = normalizeEmail(email);
const existingUser = await findUserByEmail(canonical);
if (existingUser) {
throw new Error('Email already registered');
}
await createUser({ email: canonical });
}
// Check if login email matches registration
const match = emailsMatch('user@gmail.com', 'u.s.e.r+work@gmail.com');
console.log(match); // true - same person
// Simple normalization
const canonical = normalizeEmail('u.s.e.r+work@gmail.com');
console.log(canonical); // 'user@gmail.com'Provider Support Checking
import { isEmailProviderSupported, extractDomain } from '@mikkelscheike/email-provider-links';
// Check if provider is supported
const supported = isEmailProviderSupported('user@gmail.com');
// Extract domain safely
const domain = extractDomain('USER@EXAMPLE.COM');
console.log(domain); // 'example.com'Performance and Detection System
Development Mode Features
When NODE_ENV is set to 'development', the library provides additional insights:
// Memory usage is automatically logged:
// 🚀 Current memory usage: 0.08 MBPerformance Benchmarks
Extensively optimized for both speed and memory efficiency:
Speed Metrics:
- Initial provider load: ~0.5ms
- Known provider lookup: <1ms
- DNS-based detection: ~27ms average
- Batch processing: 1000 operations in ~1.1ms
- Email validation: <1ms for complex IDN domains
Memory Management:
- Initial load: ~0.10MB heap usage
- Batch operations: ~0.00004MB per 1000 operations
- Maximum load: < 25MB under heavy concurrent operations
- Cache efficiency: >99% hit rate
- Garbage collection: Automatic optimization
Real-World Performance:
- 50,000+ operations/second for known providers
- 100 concurrent DNS lookups in <1 second
- Average latency: <1ms for cached lookups
- Maximum latency: <5ms per lookup
To run benchmarks:
# Memory usage benchmark
npm run benchmark:memory
# DNS performance benchmark
npm run benchmark:dns
# Both scripts are available in the scripts/ directory
# and can be modified for custom performance testingContributing
We welcome contributions! See CONTRIBUTING.md for guidelines on adding new email providers.
Quality Assurance: This project maintains high standards with 445 comprehensive tests achieving 94.65% code coverage (95.95% function coverage). Security Note: All new providers undergo security validation and must pass our allowlist verification.
Security
For security concerns or to report vulnerabilities, see our Security Policy.
License
MIT License - see LICENSE file for details.
Zero dependencies • TypeScript-first • Production ready • International support