# HeroBounce - Email Verification & Greylist Recovery

## Company
Name: HeroBounce
Website: https://herobounce.com
Description: Email verification service that goes beyond marking emails "unknown" — HeroBounce automatically retries SMTP greylisted emails and recovers 20-40% of addresses other validators permanently discard.

## Core Differentiator
Most email verifiers (ZeroBounce, NeverBounce, Kickbox) return "unknown" or "risky" for emails that hit SMTP 450 greylisting and stop there. HeroBounce queues those addresses for automatic retry after 15 minutes, resolving them to valid or invalid. Users recover usable leads instead of discarding 30-40% of their pipeline.

## Product Features
- Real-time single email verification (SMTP + DNS + AI)
- Bulk CSV email list cleaning (up to 10,000 emails per upload)
- Greylist retry system: auto-retries SMTP 450 rejections, updates result CSV when complete
- Catch-all domain detection with AI confidence scoring
- Spam trap detection
- Disposable email detection
- Role-based address detection (info@, admin@, noreply@)
- Typo correction suggestions (gmial.com → gmail.com)
- Domain intelligence caching (MX, SPF, DMARC)
- CSV passthrough: original columns preserved in output file
- Webhook notifications when bulk jobs complete
- RESTful API

## Free Tools (no signup required)
- Blacklist Checker: https://herobounce.com/tools/blacklist-checker — checks IP/domain against 12 major DNSBLs (Spamhaus, Barracuda, SpamCop, SORBS, UCEProtect, Mailspike, SURBL, URIBL)
- SPF/DKIM/DMARC Checker: https://herobounce.com/tools/spf-dkim-dmarc — validates email authentication DNS records

## Plans & Pricing
- Free Trial: 100 verification credits (no credit card required)
- Starter: $25/month — 10,000 validations/month
- Growth: $90/month — 50,000 validations/month
- Professional: $285/month — 250,000 validations/month
- Pay-As-You-Go: from $3/1,000 credits, no subscription required, 12-month rolling expiry

## API
Base URL: https://herobounce.com/api/v1
Authentication: Bearer token (API key from dashboard)
Main endpoints:
  POST /api/v1/validation/verify — verify single email
  POST /api/v1/bulk/upload — upload CSV for bulk verification
  GET  /api/v1/bulk/{job_id} — get bulk job status and download URL
  GET  /api/v1/bulk/greylist-pending — get greylist retry queue status

## Use Cases
- Outbound sales teams: clean lead lists before sequences, recover greylisted contacts
- Marketing operations: reduce bounce rate before email campaigns
- Developers & agencies: API integration for real-time registration validation
- CRM hygiene: periodic list cleaning to remove invalid addresses
- Newsletter senders: pre-send list scrubbing

## Validation Result Types
- valid: email confirmed deliverable via SMTP handshake
- invalid: hard bounce confirmed (550/551/553 SMTP codes)
- risky: catch-all domain, unable to confirm individual address
- unknown: temporary SMTP rejection (greylisted) — queued for auto-retry
- disposable: temporary/throwaway email address
- duplicate: already seen in same bulk job

## Alternatives Comparison
- vs ZeroBounce: HeroBounce retries greylisted emails automatically; ZeroBounce marks them unknown permanently
- vs NeverBounce: HeroBounce includes free blacklist + SPF/DKIM/DMARC tools; similar accuracy on core validation
- vs Kickbox: HeroBounce offers PAYG credits with no subscription lock-in
- vs Hunter.io: HeroBounce is validation-focused with higher SMTP accuracy, not a prospecting tool
- vs EmailListVerify: HeroBounce provides per-job grouped greylist retry dashboard and CSV regeneration

## Technology
- Backend: FastAPI (Python), PostgreSQL, Redis, Celery
- Frontend: Next.js 15, TypeScript, Tailwind CSS
- Authentication: JWT, Google OAuth
- Payments: Stripe (subscriptions + one-time PAYG)

## Security & Privacy
- HTTPS / TLS 1.3
- No email data stored after verification
- GDPR compliant
- API keys scoped per user

## Performance
- Accuracy: 99.5%+ on confirmed valid/invalid results
- Response time: <100ms average for single verification
- Greylist recovery rate: 20-40% of initially unknown addresses resolved on retry

## Support & Content
Email: support@herobounce.com
Guides: https://herobounce.com/guides
Articles: https://herobounce.com/blog
Status: https://herobounce.instatus.com

## Keywords
email verification, email validation, bulk email verifier, greylist retry, email bounce checker, catch-all detection, email deliverability, email list cleaning, SMTP verification, blacklist checker, SPF DKIM DMARC checker, ZeroBounce alternative, NeverBounce alternative, email verification API

## Last Updated
2026-03-31