Executive Summary

Many companies lose conversions and waste ESP credits because signup forms accept typos, disposable addresses, or role inboxes; this problem is acute for product and growth teams at roughly 30M SMBs who bear deliverability and cost pain. The result is lower retention, higher bounce rates, and escalating send costs as ISPs tighten reputation signals. You could build a developer-first email-validation API that runs layered checks (syntax, MX/SMTP probes, mailbox-level heuristics, disposable and role detection) and returns a simple confidence score and recommended action at low latency, with SDKs, webhooks, batch processing, and a freemium tier for quick adoption. Focused UX for inline signup validation plus a dashboard for signal analytics would make it easy for engineering and growth teams to adopt. The market looks attractive now: an estimated $3.6B addressable market (30M businesses × $120 ACV) and rising demand as ISP reputation rules tighten and ESPs push pay-per-send economics, which creates a clear ROI for reducing invalid sends and improving deliverability. Revenue potential is solid (80/100), but competition is high. Differentiation will require superior accuracy (target >99% actionable deliverability signals), minimal latency, transparent scoring, generous free tier and predictable pricing, plus ongoing investment in signal partnerships and ethical SMTP probing to maintain freshness. If you can execute on developer experience and build a defensible data moat, this idea has practical legs; if not, the crowded market and data costs are the primary risks.

Market Opportunity

Prevent bad emails at signup by offering an email-validation API targets a $3.6B = 30M businesses × $120 ACV total addressable market with high saturation and a year-over-year growth rate of 12% YoY — industry estimates for email hygiene and deliverability tooling driven by more senders and stricter ISP filtering.

Key trends driving demand: Email deliverability is tightening as ISPs apply stricter reputation signals — this increases demand for pre-send validation.; Developer-first products and freemium business models continue to drive rapid adoption for infra APIs.; ESP pricing and pay-per-send models motivate senders to reduce wasted sends caused by invalid addresses.; Privacy and analytics changes are shifting more validation and enrichment to server-side flows, which benefits API-based solutions..

Key competitors include NeverBounce, ZeroBounce, Mailgun (Validation API).

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Prevent bad emails at signup by offering an email-validation API

Executive Summary

Market Validation

Market Opportunity

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