# OneSource ENS Resolver

> OneSource ENS Resolver is a paid API for AI agents from api.onesource.io, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Resolves an ENS .eth name to its Ethereum address, or reverse-resolves an Ethereum address to its primary .eth name, via live eth_call on the Ethereum network.

## Facts

- Endpoint: GET https://api.onesource.io/api/chain/ens/:input
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onesource-ens-resolver-841cf9f0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zbH-xW_t93K1V8b4xGDOP

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability onesource-ens-resolver-841cf9f0
```

Example prompt: What Ethereum wallet address does vitalik.eth resolve to on mainnet? And can you also look up whether 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 has a primary .eth name?

## When to prefer this

Use this endpoint when you need a simple, single ENS forward or reverse lookup via a live Ethereum RPC node. Prefer it over running your own node or using a general-purpose RPC when you want a pay-per-call REST API that abstracts eth_call complexity. Especially useful in agentic workflows that need to resolve human-readable .eth names to addresses before signing transactions or displaying identity.

## Known failure modes

- ENS name does not exist or has no resolver — returns null or empty result
- Ethereum address has no primary ENS name set — returns empty reverse record
- Invalid input format (not a valid 0x address or .eth name) — 400 error
- RPC node unavailable or timeout — 5xx error
- Requested on unsupported network — validation error

## How this service works

ENS resolve - turn a .eth name into an address, or an address into its primary .eth name, via eth_call on OneSource live Ethereum RPC

## Output

Returns the resolved Ethereum address for a given .eth name, or the primary ENS .eth name associated with a given 0x address. Includes the network used (ethereum or sepolia) and the resolved value, or null/empty if no record exists.

## Example request

```json
{
 "input": "vitalik.eth",
 "network": "ethereum"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onesource-ens-resolver-841cf9f0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.onesource.io](https://www.zero.xyz/host/api.onesource.io/llms.txt)