BounceZero

About the startup

BounceZero validates email addresses at the mailbox level — not just syntax or DNS. It runs real SMTP probes, detects catchalls, scores each address with a Bayesian model trained on millions of real bounce signals, and returns a verdict: valid, invalid, risky, or unknown. Built for teams that send at scale and can't afford bounces wrecking their sender reputation. What it does: — Single and bulk email validation via API or CSV upload — SMTP probe network across multiple IPs to avoid false negatives — Catchall detection with domain-level intelligence — MX, DNS, and syntax checks as first-pass filters — Confidence scoring from 0–100, not just pass/fail — Real-time API with sub-second response for single lookups — Bulk jobs up to 1M emails with progress tracking Free tier includes credits that never expire. No credit card required