ENS Resolver API

Resolve ENS names to ETH addresses and reverse -- avatar URLs included. Identity layer for agents. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

{
  "mcpServers": {
    "ens-resolver": {
      "url": "https://ens-resolver.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://ens-resolver.api.klymax402.com/api/resolve" \
  -H "Content-Type: application/json" \
  -d '{}'
# -> 402 Payment Required, with an x402 payment challenge in the response body

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

Tool	Method	Path	Price	Description
`crypto_resolve_ens`	POST	`/api/resolve`	$0.005	Resolve ENS name to Ethereum address or reverse-resolve address to ENS name

`crypto_resolve_ens`

Use this when you need to resolve an ENS name to an Ethereum address, or reverse-resolve an address to its ENS name. Returns resolution data in JSON.

Parameters

Name	Type	Required	Description
`name`	string	no	ENS name to resolve (e.g. vitalik.eth)
`address`	string	no	Ethereum address for reverse resolution (e.g. 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045)

Returns

address -- resolved Ethereum address (0x...)
ensName -- ENS name (e.g. vitalik.eth)
avatar -- avatar URL associated with the ENS name (if set)
resolvedDirection -- "forward" (name to address) or "reverse" (address to name)

Example response:

{"address":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045","ensName":"vitalik.eth","avatar":"https://...","resolvedDirection":"forward"}

When to use: sending funds to an ENS name to verify the correct address. Essential for identity resolution and human-readable wallet lookup.

Not for: wallet balances (use wallet_get_portfolio), token safety (use token_check_safety), NFT metadata (use crypto_get_nft_metadata).

Example agent prompts

"Resolve an ENS name to an Ethereum address, or reverse-resolve an address to its ENS name"

Payment

Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
Network: Base L2 (eip155:8453)
Asset: USDC
Facilitator: Coinbase CDP (primary), PayAI (fallback)
Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)

Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

Catalog: https://klymax402.com/llms.txt
Full API reference: https://klymax402.com/llms-full.txt
Live stats: https://klymax402.com/stats

License

MIT