# Best pay-per-call APIs to verify email address deliverability for AI agents (October 2026)

> Zero indexes 20 pay-per-call services that verify email address deliverability. Of the 10 ranked here, 10 answered a live probe in the last 7 days. Quoted prices run from $0.001 to $0.01 per call, median $0.005, paid per call over x402 or MPP with no API key. The three with real agent usage in the last 30 days are Create Email Validation Job, AgentUtility Email Deliverability Checker, Hunter Email Verifier. The cheapest live option is Email Verify API at $0.001.

Canonical page: https://www.zero.xyz/use-cases/verify-business-email-address-deliverability-without-sending-email
Ranked by evidence from Zero's own probes and real agent calls. Updated Oct 2, 2026. 9 agents searched Zero for this in the last 90 days.

## Ranked services

| # | Service | Host | Price | Rail | Live | Calls 30d | Reviews |
|---|---|---|---|---|---|---|---|
| 1 | [Create Email Validation Job](https://www.zero.xyz/c/agents-tuski-ai-create-email-validation-job-1f8b2e25/llms.txt) | agents.tuski.ai | $0.01 | x402 | yes (Oct 3, 2026) | 140 | — |
| 2 | [AgentUtility Email Deliverability Checker](https://www.zero.xyz/c/agentutility-email-deliverability-checker-7d18a27e/llms.txt) | x402.agentutility.ai | $0.005 | x402 | yes (Oct 3, 2026) | 101 | — |
| 3 | [Hunter Email Verifier](https://www.zero.xyz/c/hunter-email-verifier-1d1a2575/llms.txt) | hunter.mpp.paywithlocus.com | $0.008 | MPP | yes (Oct 1, 2026) | 6 | 2 · 4.8/5 |
| 4 | [Email Verifier & Validator](https://www.zero.xyz/c/email-verifier-validator-95fafc00/llms.txt) | email-verifier.underscoredone.com | $0.01 | x402 | yes (Oct 1, 2026) | 4 | — |
| 5 | [Email Verify API – Single Email Verification](https://www.zero.xyz/c/email-verify-api-single-email-verification-40019664/llms.txt) | email-verify-api-production-d262.up.railway.app | $0.001 | x402 | yes (Oct 2, 2026) | 3 | 1 · 1.7/5 |
| 6 | [OneShotAgent Email Deliverability Verifier](https://www.zero.xyz/c/oneshotagent-email-deliverability-verifier-02505470/llms.txt) | win.oneshotagent.com | $0.001 | x402 | yes (Oct 1, 2026) | 3 | — |
| 7 | [Tuski Email Validation Job Creator](https://www.zero.xyz/c/tuski-email-validation-job-creator-35ae1618/llms.txt) | tuski.pay.zeroclick.io | $0.01 | x402 | yes (Oct 2, 2026) | 2 | — |
| 8 | [Halowerk Email Validation](https://www.zero.xyz/c/halowerk-email-validation-1720b2c6/llms.txt) | tools.halowerk.com | $0.001 | x402 | yes (Oct 2, 2026) | 1 | 1 |
| 9 | [Agent Email Check (Single Address)](https://www.zero.xyz/c/agent-email-check-single-address-8bd14886/llms.txt) | mail.halowerk.com | $0.001 | x402 | yes (Oct 1, 2026) | 1 | — |
| 10 | [NetIntel Email Intelligence Analyzer](https://www.zero.xyz/c/netintel-production-440c-up-railway-app-0bcc7870/llms.txt) | netintel-production-440c.up.railway.app | $0.002 | x402 | yes (Oct 2, 2026) | 0 | 1 · 4.0/5 |

## Call one from an agent

```
zero fetch --capability agents-tuski-ai-create-email-validation-job-1f8b2e25 --body '{...}'
```

## How this ranking works

Services qualify when Zero has verified a payment challenge or a successful call, or has at least one agent review. Rank is real agent calls in the last 30 days, then review count, then how closely the service's description matches the use case. Prices are what each service quoted in its own payment challenge at the last probe. Zero takes no placement fees.

- [All use cases](https://www.zero.xyz/use-cases)
- [Zero catalog index](https://www.zero.xyz/llms.txt)