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Sign Endpoint

Sign messages and transactions without broadcasting them to the network.

Endpoint​

POST /wallet/sign

Requires: Wallet & Agent API enabled, non-read-only key.

Overview​

The sign endpoint supports three signature types:

  • personal_sign — Sign a plain text message
  • eth_signTypedData_v4 — Sign EIP-712 structured data
  • eth_signTransaction — Sign a transaction without submitting it

This is a synchronous endpoint that returns immediately with the signature.

Request​

personal_sign​

{
  "signatureType": "personal_sign",
  "message": "Hello, Bankr!"
}

eth_signTypedData_v4​

{
  "signatureType": "eth_signTypedData_v4",
  "typedData": {
    "domain": { "name": "MyApp", "version": "1", "chainId": 8453 },
    "types": {
      "Message": [{ "name": "content", "type": "string" }]
    },
    "primaryType": "Message",
    "message": { "content": "Hello" }
  }
}

eth_signTransaction​

{
  "signatureType": "eth_signTransaction",
  "transaction": {
    "to": "0x...",
    "chainId": 8453,
    "value": "1000000000000000000"
  }
}

Response​

Success (200 OK)​

{
  "success": true,
  "signature": "0xabc123...",
  "signer": "0x1234...5678",
  "signatureType": "personal_sign"
}

Error (403)​

{
  "error": "Read-only API key",
  "message": "This API key has read-only access..."
}

Access Control​

  • Read-only keys are rejected with 403
  • Allowed recipients configured on the key will block eth_signTransaction and eth_signTypedData_v4 (can't verify recipients from calldata). personal_sign is always allowed since it cannot authorize fund movements.

Examples​

curl​

curl -X POST https://api.bankr.bot/wallet/sign \
  -H "X-API-Key: your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{"signatureType":"personal_sign","message":"Hello, Bankr!"}'

Bankr CLI​

bankr wallet sign --type personal_sign --message "Hello, Bankr!"
bankr wallet sign --type eth_signTransaction --transaction '{"to":"0x...","chainId":8453}'

Backward Compatibility​

POST /agent/sign still works but is deprecated and requires walletApiEnabled.