# MailTester, free: Email verification API

> Stop bad emails at the front door [...] fake, mistyped and disposable addresses never reach your database. REST, sane result codes, free tier.

MailTester's email verification API on its 100 free verifications plan. It costs $0.00 per 1,000 emails. It returns 3 of the 6 key fields we check: Address, Deliverability, Confidence.
In [our email verification API benchmark](https://datacircle.dev/best-email-verification-api.txt), MailTester's best plan scores 56.0 out of 100.
This plan is free. We rank 3,338 plans for email verification APIs by price. Half the plans cost $1.98 per 1,000 emails or less.
[treg's top-up from $10](https://datacircle.dev/validate-email-apis/treg/top-up-from-10/llms.txt) is the cheapest paid plan per 1,000 emails: $0.00 on average. treg asks one provider after another until one answers. You pay $68.365 per 1,000 emails when no provider answers.
[Disify's $9 monthly plan (/email)](https://datacircle.dev/validate-email-apis/disify/9-monthly-starter-post-email/llms.txt) covers any number of emails. Disify's $9 monthly plan costs less up front than treg's top-up from $10.
[MailTester Ninja](https://datacircle.dev/validate-email-apis/mailtester-ninja/23-99-monthly/llms.txt), [Enrich.so](https://datacircle.dev/validate-email-apis/enrich-so/499-monthly/llms.txt) and [GetProspect](https://datacircle.dev/validate-email-apis/getprospect/369-pack/llms.txt) are the best email verification API providers in our benchmark.

- This page: https://datacircle.dev/validate-email-apis/mailtester/free
- [Email validation API: 160+ providers compared](https://datacircle.dev/best-email-verification-api.txt)
- Get it: https://mailtester.com/pricing?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- Request: `POST https://app.mailtester.com/api/v1/verify`
- API key: with the plan, on https://mailtester.com/pricing?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- Its API docs: https://app.mailtester.com/agent-gateway/openapi.json?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- Sold by: MailTester (https://mailtester.com?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing)
- Checked: 2026-11-02

## In the answer

- Completeness: 50%
- Address: ✓
- Deliverability: ✓
- Confidence: ✓

## Price

- $ per 1,000 emails: $0.00
- Per: call
- Billing: free

## Aggregators

- Aggregators: none

## Charges

- Also pays for: nothing else

## Overage

- Units cap: hard

## Not found

- $ per 1,000: $0.00

## Catch-all

- $ per 1,000: $0.00

## In their words

- Their pitch: Stop bad emails at the front door [...] fake, mistyped and disposable addresses never reach your database. REST, sane result codes, free tier.

## Data

- Freshness: live
- What it checks: format, mail servers, disposable domains, role addresses, mailbox
- Keep data: no limit
- Use data: You may only verify addresses you have a lawful basis to process. You may not use the service to facilitate spam, to validate harvested or purchased lists for unsolicited mail, or in violation of applicable law including the GDPR, CAN-SPAM and CASL.

## Plan

- Pay: $0
- You get: 100 credits
- Enough for: 100 calls, once

## Rate limit

- Batch: 1

## Speed

- Answer: in the call
- Median: 0.64 s

## The call

- You send: email
- Method: POST
- Path: /api/v1/verify

## About the plan

- Plan: 100 free verifications
- Who can get it: anyone with a new account, no credit card required

## The 12 fields the plan's answer can hold

result, reason, score, role, free, disposable, accept-all, spam trap, did you mean, MX records, SMTP provider, email

## MailTester's plans (16)

- [MailTester, free](https://datacircle.dev/validate-email-apis/mailtester/free/llms.txt): $0.00 per 1,000, 50% complete, live
- [MailTester, $19 pack](https://datacircle.dev/validate-email-apis/mailtester/19-pack/llms.txt): $3.80 per 1,000, 50% complete, live
- [MailTester, $29 pack](https://datacircle.dev/validate-email-apis/mailtester/29-pack/llms.txt): $2.90 per 1,000, 50% complete, live
- [MailTester, $49 pack](https://datacircle.dev/validate-email-apis/mailtester/49-pack/llms.txt): $1.633 per 1,000, 50% complete, live
- [MailTester, $79 pack](https://datacircle.dev/validate-email-apis/mailtester/79-pack/llms.txt): $1.58 per 1,000, 50% complete, live
- [MailTester, $159 pack](https://datacircle.dev/validate-email-apis/mailtester/159-pack/llms.txt): $1.59 per 1,000, 50% complete, live
- [MailTester, $299 pack](https://datacircle.dev/validate-email-apis/mailtester/299-pack/llms.txt): $0.997 per 1,000, 50% complete, live
- [MailTester, $399 pack](https://datacircle.dev/validate-email-apis/mailtester/399-pack/llms.txt): $0.798 per 1,000, 50% complete, live
- [MailTester, $499 pack](https://datacircle.dev/validate-email-apis/mailtester/499-pack/llms.txt): $0.499 per 1,000, 50% complete, live
- [MailTester, $999 pack](https://datacircle.dev/validate-email-apis/mailtester/999-pack/llms.txt): $0.40 per 1,000, 50% complete, live
- [MailTester, $1,699 pack](https://datacircle.dev/validate-email-apis/mailtester/1699-pack/llms.txt): $0.34 per 1,000, 50% complete, live
- [MailTester, $2,999 pack](https://datacircle.dev/validate-email-apis/mailtester/2999-pack/llms.txt): $0.30 per 1,000, 50% complete, live
- [MailTester, $79 monthly](https://datacircle.dev/validate-email-apis/mailtester/79-monthly/llms.txt): $0.527 per 1,000, 50% complete, live
- [MailTester, $199 monthly](https://datacircle.dev/validate-email-apis/mailtester/199-monthly/llms.txt): $0.663 per 1,000, 50% complete, live
- [MailTester, $299 monthly](https://datacircle.dev/validate-email-apis/mailtester/299-monthly/llms.txt): $0.399 per 1,000, 50% complete, live
- [MailTester, contact us](https://datacircle.dev/validate-email-apis/mailtester/contact-us/llms.txt): 50% complete, live

## MailTester's calls (1)

- `POST /api/v1/verify`: [MailTester, free](https://datacircle.dev/validate-email-apis/mailtester/free/llms.txt)

## MailTester's APIs (1)

- [MailTester: email verification API pricing, 16 plans](https://datacircle.dev/validate-email-apis/mailtester/free/llms.txt)

## MailTester: email verification API alternatives

- [BillionVerify, $720 yearly, Business, POST /verify/bulk](https://datacircle.dev/validate-email-apis/billionverify/720-yearly-business-post-verify-bulk/llms.txt): $0.30 per 1,000, 67% complete, live
- [NullBounce, $1,500 pack](https://datacircle.dev/validate-email-apis/nullbounce/1500-pack/llms.txt): $0.30 per 1,000, 33% complete, live
- [BounceVerify, $150 pack, Ultimate, POST /api/verify/bulk](https://datacircle.dev/validate-email-apis/bounceverify/150-pack-ultimate-post-api-verify-bulk/llms.txt): $0.30 per 1,000, 50% complete, live
- [VerifyHQ, $750 pack](https://datacircle.dev/validate-email-apis/verifyhq/750-pack/llms.txt): $0.30 per 1,000, 33% complete, live

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-11-02.

- https://app.mailtester.com/agent-gateway/openapi.json?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- https://mailtester.com?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- https://mailtester.com/api-email-checker?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- https://mailtester.com/faq?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- https://mailtester.com/pricing?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- https://mailtester.com/terms?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing