# Best pay-per-call whois lookup APIs for AI agents (October 2026)

> Zero indexes 10 pay-per-call services for whois lookup: 10 of the 10 ranked here answered a live probe in the last 7 days, quoted from $0.001 to $0.054 per call (median $0.006) over x402 or MPP with no API key; the cheapest live option is WHOIS Lookup at $0.001. The two with real agent usage in the last 30 days are agentsvc.io WHOIS Lookup, agentsvc.io Domain Check. Agents call any of them through Zero, which pays per call: no API key and no wallet of your own. New accounts start with $5.

Canonical page: https://www.zero.xyz/use-cases/whois-lookup
Ranked by evidence from Zero's own probes and real agent calls. Updated Oct 26, 2026. 5 agents searched Zero for this in the last 90 days.

## Ranked services

| # | Service | Host | Price | Rail | Live | Calls 30d | Reviews |
|---|---|---|---|---|---|---|---|
| 1 | [agentsvc.io WHOIS Lookup](https://www.zero.xyz/c/agentsvc-io-whois-lookup-578fab64/llms.txt) | agentsvc.io | $0.0045 | x402 | yes (Oct 31, 2026) | 1 | — |
| 2 | [agentsvc.io Domain Check](https://www.zero.xyz/c/agentsvc-io-domain-check-eb0946e0/llms.txt) | agentsvc.io | $0.009 | x402 | yes (Oct 30, 2026) | 1 | — |
| 3 | [WHOIS Lookup (RDAP)](https://www.zero.xyz/c/zeroclick-x402-service-registry-whois-lookup-0d3f4508/llms.txt) | whois.withzero.ai | $0.001 | MPP | yes (Oct 29, 2026) | 0 | 1 · 4.7/5 |
| 4 | [402utils Domain Check (RDAP)](https://www.zero.xyz/c/402utils-domain-check-rdap-4aee3a4b/llms.txt) | 402utils.com | $0.002 | x402 | yes (Oct 27, 2026) | 0 | 1 · 5.0/5 |
| 5 | [2s.io Domain WHOIS via RDAP](https://www.zero.xyz/c/2s-io-add6f158/llms.txt) | 2s.io | $0.001 | x402 | yes (Oct 30, 2026) | 0 | — |
| 6 | [domain.hugen.tokyo WHOIS Lookup](https://www.zero.xyz/c/domain-hugen-tokyo-61d76363/llms.txt) | domain.hugen.tokyo | $0.01 | x402 | yes (Oct 30, 2026) | 0 | — |
| 7 | [WHOIS / RDAP Domain Lookup](https://www.zero.xyz/c/x402-deployer-x402-deployer-workers-dev-d989c7b0/llms.txt) | x402-deployer.x402-deployer.workers.dev | $0.02 | x402 | yes (Oct 30, 2026) | 0 | — |
| 8 | [WHOIS Domain Lookup](https://www.zero.xyz/c/api-strale-io-14ed8463/llms.txt) | api.strale.io | $0.054 | x402 | yes (Oct 30, 2026) | 0 | — |
| 9 | [2s Domain Intelligence Lookup](https://www.zero.xyz/c/2s-domain-intelligence-lookup-4021d141/llms.txt) | 2s.io | $0.0048 | x402 | yes (Oct 27, 2026) | 0 | — |
| 10 | [The Stall — Domain WHOIS Lookup](https://www.zero.xyz/c/the-stall-domain-whois-lookup-d5f953b8/llms.txt) | the-stall.intuitek.ai | $0.006 | x402 | yes (Oct 30, 2026) | 0 | — |

## Call one from an agent

```
zero fetch --capability agentsvc-io-whois-lookup-578fab64 --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.

## Related use cases

- [domain lookup APIs](https://www.zero.xyz/use-cases/domain-lookup/llms.txt)
- [ip geolocation APIs](https://www.zero.xyz/use-cases/ip-geolocation/llms.txt)
- [APIs to host static website](https://www.zero.xyz/use-cases/host-static-website/llms.txt)
- [APIs to geocode an address](https://www.zero.xyz/use-cases/geocode-an-address/llms.txt)

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