# Facts402, pay as you go: Email verification API

> Use when an agent needs email validation before sending or saving a signup: RFC syntax and normalisation, live DNS (domain exists, MX, accepts mail, null MX), disposable-domain and role-account (info@, support@) flags. No SMTP probing and no mail sent, so it cannot prove a mailbox exists.

Facts402's x402 pay per call plan for the email verification API costs $10.00 per 1,000 emails. We check each provider's docs for 6 fields. Facts402's docs list 3: Address, Deliverability, Company.
We haven't run Facts402 through [our email verification API benchmark](https://datacircle.dev/best-email-verification-api.txt) yet.
We rank 4,337 plans for email verification APIs by price. Half the plans cost $2.00 or less per 1,000 emails. This plan costs less per 1,000 emails than 10% of the 4,337 plans.
[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. [StableEnrich's pay-as-you-go plan](https://datacircle.dev/validate-email-apis/stableenrich/pay-as-you-go-pay-per-request-with-x402-or-mpp-post-api-minerva-validate-emails/llms.txt) costs the least for 10,000 emails a month: $0.05.
[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.
[pingutil](https://datacircle.dev/validate-email-apis/pingutil/free-api-key-post-v1-verify/llms.txt), [Validemail.co](https://datacircle.dev/validate-email-apis/validemail-co/9-90-monthly-9-90-month-get-api-v1-validate/llms.txt) and [looot](https://datacircle.dev/validate-email-apis/looot/top-up/llms.txt) are the best email verification API providers in the Datacircle benchmark.

- This page: https://datacircle.dev/validate-email-apis/facts402/pay-as-you-go
- [Email validation API: best verification providers compared](https://datacircle.dev/best-email-verification-api.txt)
- Get it: https://api.facts402.com/?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- Request: `POST https://api.facts402.com/email`
- API key: not needed
- Its API docs: https://api.facts402.com/openapi.json?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing#/paths/~1email
- Sold by: Facts402 (https://api.facts402.com?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing)
- Checked: 2026-11-09

## In the answer

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

## Price

- $ per 1,000 emails: $10.00
- Per: call
- Billing: pay as you go

## Aggregators

- Aggregators: none

## Charges

- Also pays for: nothing else

## Not found

- $ per 1,000: $0.00

## In their words

- Their pitch: Use when an agent needs email validation before sending or saving a signup: RFC syntax and normalisation, live DNS (domain exists, MX, accepts mail, null MX), disposable-domain and role-account (info@, support@) flags. No SMTP probing and no mail sent, so it cannot prove a mailbox exists.

## Data

- What it checks: format, mail servers, disposable domains, role addresses
- Keep data: no API terms
- Use data: no API terms

## Plan

- Pay: per call

## Rate limit

- Batch: 1

## Speed

- Answer: in the call

## The call

- You send: email
- Method: POST
- Path: /email

## About the plan

- Plan: x402 pay per call
- Who can get it: anyone with a wallet paying USDC on Base (x402 v2), with no account or API key

## The 13 fields the plan's answer can hold

email address, normalized email address, local part, domain, valid syntax, domain exists, MX records, implicit MX, null MX, accepts mail, disposable domain, role account, disclaimer

## Facts402's plans (1)

- [Facts402, pay as you go](https://datacircle.dev/validate-email-apis/facts402/pay-as-you-go/llms.txt): $10.00 per 1,000, 50% complete

## Facts402's calls for this API (1)

- `POST /email`: [Facts402, pay as you go](https://datacircle.dev/validate-email-apis/facts402/pay-as-you-go/llms.txt)

## Facts402's APIs (4)

- [Facts402: domain WHOIS API pricing, 1 plan](https://datacircle.dev/domain-whois-apis/facts402/pay-as-you-go/llms.txt)
- [Facts402: email verification API pricing, 1 plan](https://datacircle.dev/validate-email-apis/facts402/pay-as-you-go/llms.txt)
- [Facts402: phone validation API pricing, 1 plan](https://datacircle.dev/validate-phone-apis/facts402/pay-as-you-go/llms.txt)
- [Facts402: company enrichment API pricing, 1 plan, POST /vat](https://datacircle.dev/company-enrichment-apis/facts402/pay-as-you-go-x402-pay-per-call-post-vat/llms.txt)
- [Facts402: company enrichment API pricing, 1 plan, POST /lei](https://datacircle.dev/company-enrichment-apis/facts402/pay-as-you-go-x402-pay-per-call-post-lei/llms.txt)

## Facts402: email verification API alternatives

- [Tuski, pay as you go](https://datacircle.dev/validate-email-apis/tuski/pay-as-you-go/llms.txt): $10.00 per 1,000, 50% complete
- [Clearout, $1,000 pack, 500,000 credits, POST /email_verify/instant, Instant Verify, full](https://datacircle.dev/validate-email-apis/clearout/1000-pack-500000-credits-post-email-verify-instant-instant-verify-full/llms.txt): $10.00 per 1,000, 50% complete, live
- [InboxPolicy, pay as you go, Pay-per-call (x402), POST /v1/decide](https://datacircle.dev/validate-email-apis/inboxpolicy/pay-as-you-go-pay-per-call-x402-post-v1-decide/llms.txt): $10.00 per 1,000, 50% complete, 72 hours
- [Catch-all Verifier, $25 pack, 2,500 Credits, POST /api/v1/verify/single](https://datacircle.dev/validate-email-apis/catch-all-verifier/25-pack-2500-credits-post-api-v1-verify-single/llms.txt): $10.00 per 1,000, 33% complete, live
- [AgentX.sale, pay as you go](https://datacircle.dev/validate-email-apis/agentx-sale/pay-as-you-go/llms.txt): $10.00 per 1,000, 33% complete

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-11-09.

- https://api.facts402.com/?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- https://api.facts402.com/.well-known/x402?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- https://api.facts402.com/llms.txt?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing
- https://api.facts402.com/openapi.json?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=email-verification-api-pricing