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emailzeno vs Mails.so:
which is better for startups and API-first developers?

Both are modern API-first verification tools — emailzeno offers lower flat-rate pricing and native EU hosting.

Try free — 300 verifications See full comparison

All competitor data sourced from public pricing and documentation pages. ¹ Footnote marks denote claims verified as of 2026-05-20.

TL;DR — winner per dimension

✅ Pricing model
➖ Accuracy claim
➖ Free tier
✅ Integrations
➖ REST API
✅ Refund policy
✅ GDPR / EU hosting
✅ Support SLA

✅ emailzeno wins  ·  ⚠️ Mails.so wins  ·  ➖ Tie

Feature-by-feature: emailzeno vs Mails.so

Dimension EmailZeno Mails.so Winner
Pricing model Flat $9–$79/mo unlimited¹ Per-credit + monthly subscription¹ ✅
Accuracy claim 99.6 % (SMTP + MX layer) 99.5 % stated on site¹ ➖
Free tier 300 verifications, no card 100 free verifications¹ ➖
Integrations 35+ via native + Zapier Zapier + limited native¹ ✅
REST API Full REST + webhooks REST API + webhooks¹ ➖
Refund policy Auto-credit on hard bounces No refund policy stated¹ ✅
GDPR / EU hosting EU-hosted by default US servers, EU option paid¹ ✅
Support SLA Email + chat, 24 h SLA Email support only¹ ✅

¹ Competitor data verified from public sources as of 2026-05-20. Pricing and features may change — check the competitor's site for the latest.

Pricing side-by-side

EmailZeno
  • Free $0 300 verifications/mo
  • Solo $9 5 000 verifications/mo
  • Growth $29 25 000 verifications/mo
  • Unlimited $39 Unlimited flat rate
  • Scale $79 100 000 verifications/mo
Start free
Mails.so
  • Starter $19/mo 2 500 verifications/mo¹
  • Growth $49/mo 10 000 verifications/mo¹
  • Pro $149/mo 50 000 verifications/mo¹

¹ As of 2026-05-20. Check their site for latest pricing.

When Mails.so is the better pick

Mails.so has a clean, modern developer dashboard with good documentation and quick onboarding. Their API-first approach appeals to engineering teams that want to integrate verification into sign-up flows. Their Starter plan ($19/mo, 2 500 verifications) is competitively priced for very low-volume users who prefer a subscription model but don't need unlimited throughput.

When emailzeno is the better pick

emailzeno offers more value at every volume tier above 2 500/mo. Our Growth plan covers 25 000 verifications for $29 — Mails.so charges $149 for 50 000 (2× the price for 2× the volume, worse unit economics). EU hosting is our default, no upcharge. Our auto-refund policy and larger integration ecosystem (35+ vs limited native) make us the more complete platform for growing teams.

Moving from Mails.so?

Migrating from Mails.so? Export your verification results CSV from their dashboard — their status column uses valid, invalid, and catch_all categories. Map invalid rows to emailzeno's suppression list. Both APIs support JSON POST at similar endpoints; the migration is primarily a credential swap.

Import your suppression list →

Ready to try emailzeno?

300 free verifications. No credit card. Cancel any time.

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Frequently asked questions

Yes — both offer single-email API endpoints with sub-300 ms response times suitable for sign-up form verification. Both also support bulk CSV upload with webhook callbacks.

Our Growth plan ($29 for 25 000) costs less than their Growth plan ($49 for 10 000). At 50 000/mo, we're $39 (Unlimited) vs their $149 (Pro). The gap widens with volume because our Unlimited plan has no ceiling.

Both tools detect disposable/temporary email addresses and return a distinct status. We maintain our own disposable domain list updated weekly. Neither service guarantees 100% coverage of new burner domains.
Free forever — no credit card

Clean lists ship faster.
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300 verifications /mo · five-minute API integration · credit refund on hard bounces. Trusted by senders who treat sender reputation like the asset it is.

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