Mails.so vs ZeroBounce (2026): which should you pick?

Pick Mails.so if

• Fits if you want a flat monthly price instead of buying packs
• Works for people who also want an email finder

Look elsewhere if

• Watch out: the 90% first-month discount lasts one month, then the plan renews in full
• Skip it if you want a free plan, since it's 50 credits once
• Pricey if you validate small amounts, as plans start at €48 a month
• Watch out: prices were read in euros and the dollar price is unconfirmed

Pick ZeroBounce if

• Fits if you want list cleaning, warm-up and DMARC for one domain on one bill
• Works for developers who want an API with SDKs in 16 languages, or checks from an iPhone or iPad

Look elsewhere if

• Pricey if you only need a list cleaned, at about $129 for 10,000 checks
• Tight if you send from several domains, as ONE watches DMARC for just one
• Watch out: unused tests, monitors and warm-up seeds on ONE don't roll over, only verification credits do
• Watch out: the free 100 checks a month need a business email domain at sign-up
• Not for you if you're on Android or a desktop, as the only app is for iPhone and iPad

Mails.so

• Prices were read in euros; a US dollar view could not be read, so the dollar price is unconfirmed.
• The 90% first-month discount applies to the first month only; the plan then renews at full price.
• The free allowance is a one-time 50 credits, not a monthly free plan.
• Only the three paid plans were listed; there is no separate pay-as-you-go pack on the page.

ZeroBounce

• Warm-up and DMARC monitoring come only with ZeroBounce ONE, and it covers a single DMARC domain.
• Unused tests, monitors, searches and warm-up seeds on ONE do not roll over; only verification credits do.
• The FAQ says credits never expire with an active ONE subscription; otherwise expiry rules may apply depending on when they were bought.
• The free credits need a business or premium email domain at sign-up.

Mails.so

List validation

Upload a list to check its addresses, or paste single addresses into the checker on the homepage.

Validation API

Every paid plan includes API access, for checking addresses at signup or inside other software.

Email finder

An email finder is included on all three paid plans.

Mailchimp and HubSpot integrations

Listed on every paid plan for cleaning lists held in those platforms.

Top-ups

Extra validations can be bought at any time on Pro and Business at a stated per-validation rate.

ZeroBounce

Email validation

Checks lists by file upload or real-time API and flags invalid, catch-all, disposable, role-based, abuse and spam-trap addresses. Unknown results and duplicates are free.

AI scoring

An AI model scores each address for quality at one extra credit, which helps decide whether to send to catch-all and other uncertain addresses.

Email Finder

Finds a person's work address from a name and company domain, at 20 credits per successful search; unknown results cost nothing.

Warm-up and placement tests

ZeroBounce ONE includes warm-up through a seed network, inbox placement tests against 20+ providers and email server tests.

Blacklist and DMARC monitoring

Monitors IPs and domains on blacklists and gathers daily DMARC reports for one domain on the ONE plan.

API, SDKs and iOS app

A validation and scoring API with SDKs in 16 languages, an MCP server, and an iOS app for checking lists from an iPhone or iPad.

Mails.so

• Pro€48

  per month for 10,000 validations

  First month €4.80 (90% off). 5 concurrent validations; top-ups at €0.005 per validation.

• Business€98

  per month for 50,000 validations

  First month €9.80 (90% off). 5 concurrent validations; top-ups at €0.002 per validation.

• Unlimited€498

  per month for unlimited validations

  First month €49.80 (90% off). 10 concurrent validations.

ZeroBounce

• Freemium$0

  100 verification credits that refill each month, one inbox placement test, one server test and one blacklist monitor.

• Pay-As-You-Go$39

  one-time for 2,000 credits

  The minimum purchase. Per-credit rates fall with volume: about $129 for 10,000 ($0.0129 each) and $0.0032 each at 1 million.

• ZeroBounce ONE$79

  per month for 10,000 credits, billed annually ($99 monthly)

  Credits roll over, plus 250 warm-up seeds, 100 inbox tests, 100 server tests, 10 blacklist monitors, 1 DMARC domain and 15% off extra credits.

• EnterpriseCustom

  Purchases or subscriptions of more than 1 million credits, with onboarding and training.

Mails.so

• Other savings

  90% off the first month

  The homepage shows each paid plan at 90% off for the first month, then at full price. No end date is shown.

ZeroBounce

• Annual discount

  20% off ZeroBounce ONE billed annually

  ZeroBounce ONE costs $79 a month when paid annually in one charge, against $99 billed monthly.