Valid8 Email Verification

Problem

• Regex-only validation wasn’t enough for production data quality and led to higher bounce rates.
• Needed deeper verification with clear risk signals for downstream systems.

Solution

• Designed and built the backend for Valid8 with deep validation: MX lookups, SMTP handshakes, and domain-level risk profiling.
• Supports both real-time checks and bulk list verification.

How it works

• Celery handles async workloads; Redis caches repeat checks to improve performance and reduce repeated network calls.

Decisions & tradeoffs

• Optimized for accuracy and scalability using async processing instead of blocking request threads.
• Used caching to keep costs and latency under control for repeated domains/emails.

Flow

Request / CSV upload
│
├─ Queue job (Celery)
│   ├─ MX lookup
│   ├─ SMTP handshake
│   ├─ Risk profiling
│   └─ Cache results (Redis)
│
└─ Return result / export