TrueUser
TrueUser is a real-time email verification API designed to detect and prevent fraudulent signups. It helps businesses filter out disposable emails, role accounts, and batch signup attacks before they enter the user pipeline. By making a single POST request with an email (and optionally IP and user agent), developers receive a verdict (allow, review, block) along with 14 detailed signals such as disposable domain match, MX/SMTP validity, free-provider flag, and batch-cluster score. The service responds in under 80 milliseconds, allowing seamless integration into signup flows without introducing noticeable latency. TrueUser maintains a continuously updated list of over 5,400 disposable domains, crawling and fingerprinting new providers as they emerge. It also clusters incoming signups by IP block, ASN, fingerprint, timing, and email pattern to identify coordinated batch attacks in real time, reducing noisy individual alerts into a single actionable batch notification. The API is language-agnostic, requiring no SDK, and offers a live dashboard for log replay, policy tuning, and monitoring. Pricing includes a free tier for prototyping and a flat monthly fee for higher volumes, avoiding metered overage surprises.
- Category
- Security Software
- Pricing
- Unknown
Problem solved
Fraudulent signups using disposable emails and bot-driven batch attacks waste resources through unnecessary transactional emails, inflate user counts, degrade sender reputation, and consume onboarding efforts. TrueUser provides an accurate, low-latency API to detect such signups with granular signals, allowing businesses to block or review them automatically and maintain a clean, engaged user base.
Use cases
- Real-time signup form validation to block disposables
- Preventing free-tier abuse from batch account creation
- Protecting sender reputation by eliminating fake email sends
- Reducing onboarding costs for non-existent users
- Bot detection during promotional or referral campaigns
Audience
- Developers
- Product Managers
Pros
- Ultra-fast response (<80 ms)
- Single REST endpoint, no SDK needed
- 14-detailed signals for fine-grained control
- Up-to-date disposable domain list (5,400+ tracked)
- Built-in batch signup clustering
Cons
- No self-hosted option, cloud-only
- Free tier is very limited (1,000 lifetime checks)
- Email verification only, no phone or address validation
- Reliance on third-party ML (Gemini) for some detections
- Limited offline functionality without active internet
Official website: https://trueuser.dev/
Canonical LambdaBase page: https://www.lambdabase.com/tools/trueuser