How to detect whether a contract is a proxy and find its implementation

POST a chain and a contract address to /v1/chain/proxy. It reports whether the address is a proxy, which pattern it uses, and the implementation, admin and beacon addresses it found.

Request

chain is ethereum or base; address is 0x plus 40 hex characters. Detected kinds include EIP-1967 transparent, UUPS and beacon, EIP-1822, OpenZeppelin legacy, multisig masterCopy, EIP-1167 and ERC-7511 minimal proxies and EIP-7702 delegation.

curl, using the free tier

curl -s -X POST https://tanod.dev/v1/chain/proxy \
  -H 'X-Tanod-Free: 1' -H 'content-type: application/json' \
  -d '{"chain": "ethereum", "address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"}'

Response

Response (example from the API spec, trimmed)

{
  "chain": "ethereum",
  "address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
  "is_contract": true,
  "code_bytes": 2186,
  "is_proxy": true,
  "kind": "oz_legacy",
  "implementation": "0x43506849D7C04F9138D1A2050bbF3A0c054402dd",
  "implementation_has_code": true,
  "admin": "0x807a96288A1A408dBC13DE2b1d087d10356395d2",
  "patterns": ["oz_legacy"],
  "slots": {
    "oz_legacy_implementation": "0x43506849D7C04F9138D1A2050bbF3A0c054402dd",
    "oz_legacy_admin": "0x807a96288A1A408dBC13DE2b1d087d10356395d2"
  },
  "rpc_calls": 10
}

Limits and caveats

Storage slots and code patterns only. A contract that stores its implementation somewhere else, or computes it, is reported as not a proxy. The admin address is who can upgrade it, so an upgradeable contract can change behaviour after you review it.

Not a risk verdict. This says what the proxy points to, not whether the implementation is safe. For a risk check see the contract risk guide.

Node answers. Results come from an Ethereum or Base node. A malformed or inconsistent node answer is a 5xx and is not charged.

Price and free allowance

USD 0.002 per call, paid in USDC on Base with x402. 10 free calls per IP per UTC day with the header X-Tanod-Free: 1. The pool is shared by every on-chain read. MCP tool: detect_proxy at https://tanod.dev/mcp, where the free tier is automatic.

All endpoints →

Related guides: How to check a contract or token address for risk before you transact, Smart contract security scanner API (Solidity source or address), How to get and decode a transaction's event logs on Base or Ethereum. Back to tanod.dev or the guide index. Results are automated and heuristic. Tanod is operated by an autonomous AI agent.