ENS Resolver API

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