Signing

Sign messages, typed data, and raw transactions with your wallet keys

In a nutshell
The Blockradar Signing API lets you cryptographically sign plain text messages, structured data (typed data), and raw transactions using your wallet’s private keys. Sign messages to prove wallet ownership. Sign transactions built externally (e.g., Jupiter swaps on Solana) without exposing private keys, and optionally broadcast them on-chain.

Prerequisites

Before using the Signing API, ensure you have:

1. API Key

   Get your API key from the Blockradar Dashboard. Navigate to Developers to generate one.

2. Wallet Created

   Create a master wallet from the Blockradar Dashboard. Navigate to Wallets and create one for your target blockchain. You’ll need the walletId for signing operations.

3. Environment

   Choose between Testnet (for development) or Mainnet (for production). Wallets are isolated per environment.

How It Works

The Signing API produces a cryptographic signature that proves you control a specific wallet address. The signed output can be verified by any third party without accessing your private keys.

Message Signing

Sign plain text messages to prove wallet ownership. Works on all supported blockchains: EVM, Tron, and Solana.

Typed Data Signing

Sign structured data following the EIP-712 standard. Used for gasless approvals (EIP-2612 Permit) and authorized transfers (EIP-3009). EVM-only.

Transaction Signing

Sign raw transactions built externally. Build a swap on Jupiter, a contract call via ethers.js, or a TronWeb transfer, then send the unsigned tx and get it signed without exposing private keys.

Transaction Broadcast

Sign and broadcast a raw transaction in one step. Blockradar signs the transaction and submits it on-chain via a reliable queue with automatic retries.

Common use cases

• Third-party provider registration: Prove you own an address when onboarding with services like Iron, Circle, or other DeFi protocols
• Gasless token approvals: Sign EIP-2612 Permit messages to authorize token spending without an on-chain transaction
• Authorized transfers: Sign EIP-3009 TransferWithAuthorization messages for delegated transfers
• Off-chain attestations: Create verifiable proofs of intent or agreement tied to a wallet address
• External swap execution: Build a Jupiter swap on Solana, sign it with Blockradar, and broadcast it on-chain
• Custom contract interactions: Build any transaction externally and have Blockradar sign and/or submit it

Master Wallet vs Child Address

The Signing API is available at two levels:

Master Wallet

Sign using the master wallet’s keys. Ideal for treasury-level operations and provider integrations.

Child Address

Sign using a specific child address’s keys. Use when the third party requires a signature from a deposit address.

Endpoints

Operation	Master Wallet	Child Address
Sign Message	POST /v1/wallets/{walletId}/signing/message	POST /v1/wallets/{walletId}/addresses/{addressId}/signing/message
Sign Typed Data	POST /v1/wallets/{walletId}/signing/typed-data	POST /v1/wallets/{walletId}/addresses/{addressId}/signing/typed-data
Sign Transaction	POST /v1/wallets/{walletId}/signing/transaction	POST /v1/wallets/{walletId}/addresses/{addressId}/signing/transaction
Sign + Broadcast	POST /v1/wallets/{walletId}/signing/broadcast	POST /v1/wallets/{walletId}/addresses/{addressId}/signing/broadcast

---

Message Signing

Sign a plain text message with your wallet’s private key. The API signs the message, verifies the signature matches the wallet address, and returns both the signature and a transaction record.

Supported Blockchains

Blockchain	Signing Standard	Signature Format
EVM (Ethereum, Polygon, BSC, Base, Arbitrum, Optimism, Celo)	EIP-191 (personal_sign)	Hex-encoded with r, s, v components
Tron	TronWeb signMessageV2	Hex-encoded string
Solana	Ed25519	Base58-encoded string

Request Parameters

Parameter	Type	Required	Description
message	string	Yes	The plain text message to sign. Maximum 4,096 characters.
reference	string	No	Your internal tracking ID. Use for idempotency. Duplicate references are rejected.
metadata	object	No	Custom key-value pairs stored with the transaction record.

Message Signing Example

Curl

curl --request POST \
  --url https://api.blockradar.co/v1/wallets/{walletId}/signing/message \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '{
    "message": "Please sign this message to verify your wallet ownership for Iron provider registration.",
    "reference": "iron-verification-001",
    "metadata": {
      "provider": "iron",
      "purpose": "wallet-verification"
    }
  }'

EVM Response

{
  "message": "Message signed successfully",
  "statusCode": 200,
  "data": {
    "id": "770f9100-7338-4823-b1ce-3658fc67db09",
    "hash": "0xdb095e6cbf235d630cee43e0953e60c351e46897bc4e65abfce3e975810e21335aa3918399dac1e01badb2dc8c59c171e65d0c328c92737de702da9d76b889b31b",
    "status": "SUCCESS",
    "type": "SIGNED",
    "senderAddress": "0x947514e4B803e312C312da0F1B41fEDdbe15ae7a",
    "recipientAddress": "0x947514e4B803e312C312da0F1B41fEDdbe15ae7a",
    "signedTransaction": {
      "r": "0xdb095e6cbf235d630cee43e0953e60c351e46897bc4e65abfce3e975810e2133",
      "s": "0x5aa3918399dac1e01badb2dc8c59c171e65d0c328c92737de702da9d76b889b3",
      "v": 27,
      "signature": "0xdb095e6cbf...b31b"
    },
    "reference": "iron-verification-001",
    "metadata": {
      "provider": "iron",
      "purpose": "wallet-verification"
    },
    "confirmed": true,
    "createdAt": "2025-03-02T19:00:52.000Z"
  }
}

Tron / Solana Response

For Tron and Solana, the signedTransaction object contains only the signature field (no r, s, v components):

{
  "message": "Message signed successfully",
  "statusCode": 200,
  "data": {
    "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "hash": "3xYkZ9...",
    "status": "SUCCESS",
    "type": "SIGNED",
    "senderAddress": "TJRabPrwbZy45sbavfcjinPJC18kjpRT9Y",
    "recipientAddress": "TJRabPrwbZy45sbavfcjinPJC18kjpRT9Y",
    "signedTransaction": {
      "signature": "3xYkZ9..."
    },
    "reference": "tron-verification-001",
    "confirmed": true,
    "createdAt": "2025-03-02T19:00:52.000Z"
  }
}

Response Fields

Field	Description
id	Unique transaction ID for the signing record
hash	The cryptographic signature. For EVM: hex string. For Tron: hex string. For Solana: base58 string.
status	Always SUCCESS for completed signatures
type	Always SIGNED for signing transactions
senderAddress	The wallet address that produced the signature
signedTransaction	Signature components. EVM includes r, s, v, and full signature. Tron and Solana include signature only.
reference	Your provided reference string (if any)
metadata	Your provided metadata object (if any)

---

Typed Data Signing (EVM Only)

Sign structured data following the EIP-712 standard. This is used for gasless approvals, delegated transfers, and other on-chain authorization flows that require a structured signature.

Typed data signing is only available for EVM-compatible blockchains (Ethereum, Polygon, BSC, Base, Arbitrum, Optimism, Celo). Tron and Solana do not support EIP-712.

Supported Standards

Standard	Use Case
EIP-712	Generic structured data signing
EIP-2612 (Permit)	Gasless token approvals. Approve spending without an on-chain transaction
EIP-3009 (TransferWithAuthorization)	Delegated transfers. Authorize a transfer that a third party submits

Request Parameters

Parameter	Type	Required	Description
domain	object	Yes	EIP-712 domain separator. Includes name, version, chainId, and verifyingContract.
types	object	Yes	Type definitions for the structured data.
message	object	Yes	The data to sign, conforming to the type definitions.

EIP-2612 Permit Example

Curl

curl --request POST \
  --url https://api.blockradar.co/v1/wallets/{walletId}/signing/typed-data \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '{
    "domain": {
      "name": "USD Coin",
      "version": "2",
      "chainId": 11155111,
      "verifyingContract": "0xa0b86a33e6441b8c4c8c0c077bcdd28571685701"
    },
    "types": {
      "Permit": [
        { "name": "owner", "type": "address" },
        { "name": "spender", "type": "address" },
        { "name": "value", "type": "uint256" },
        { "name": "nonce", "type": "uint256" },
        { "name": "deadline", "type": "uint256" }
      ]
    },
    "message": {
      "owner": "0x742d35cc6634c0532925a3b8d4c9db96c4b4d8b6",
      "spender": "0x8ba1f109551bd432803012645aac136c4c8c8c0c",
      "value": "1000000000",
      "nonce": "0",
      "deadline": "1641081600"
    }
  }'

Typed Data Response

{
  "message": "Typed data signed successfully",
  "statusCode": 200,
  "data": {
    "id": "770f9100-7338-4823-b1ce-3658fc67db09",
    "hash": "0xdb095e6cbf235d630cee43e0953e60c351e46897bc4e65abfce3e975810e21335aa3918399dac1e01badb2dc8c59c171e65d0c328c92737de702da9d76b889b31b",
    "status": "SUCCESS",
    "type": "SIGNED",
    "senderAddress": "0x947514e4B803e312C312da0F1B41fEDdbe15ae7a",
    "recipientAddress": "0x947514e4B803e312C312da0F1B41fEDdbe15ae7a",
    "signedTransaction": {
      "r": "0xdb095e6cbf235d630cee43e0953e60c351e46897bc4e65abfce3e975810e2133",
      "s": "0x5aa3918399dac1e01badb2dc8c59c171e65d0c328c92737de702da9d76b889b3",
      "v": 27,
      "signature": "0xdb095e6cbf...b31b"
    },
    "confirmed": true,
    "createdAt": "2025-03-02T19:00:52.000Z"
  }
}

Domain Object Fields

Field	Type	Required	Description
name	string	Yes	The name of the signing domain (e.g., the token name or dApp name)
version	string	Yes	The version of the domain
chainId	number	Yes	The chain ID. Must match the wallet’s blockchain network.
verifyingContract	string	Yes	The contract address that will verify the signature
salt	string	No	Optional domain salt for EIP-712 v4

Chain ID validation
The chainId in your domain object must match the chain ID of the wallet’s blockchain network. If they don’t match, the API returns a 400 Chain ID mismatch error.

---

Child Address Signing

Sign messages, typed data, transactions, or broadcast using a specific child address instead of the master wallet. All four signing operations are available for child addresses:

Curl

curl --request POST \
  --url https://api.blockradar.co/v1/wallets/{walletId}/addresses/{addressId}/signing/message \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '{
    "message": "Verify ownership of deposit address for provider onboarding.",
    "reference": "address-verify-001"
  }'

Child address signing follows the same request and response format as master wallet signing. The only difference is the endpoint URL, which includes the addressId.

---

Webhook Events

Signing operations trigger a webhook with the transaction record:

Event	Description
signed.success	Signing completed successfully. For message/typed data/transaction sign, this fires immediately. For broadcast, this fires after on chain confirmation.
signed.failed	Transaction broadcast failed after all retries were exhausted. Only applies to the /broadcast endpoint.

Webhook Payload (Message or Typed Data Signing)

{
  "event": "signed.success",
  "data": {
    "id": "770f9100-7338-4823-b1ce-3658fc67db09",
    "hash": "0xdb095e6cbf...b31b",
    "status": "SUCCESS",
    "type": "SIGNED",
    "senderAddress": "0x947514e4B803e312C312da0F1B41fEDdbe15ae7a",
    "recipientAddress": "0x947514e4B803e312C312da0F1B41fEDdbe15ae7a",
    "signedTransaction": {
      "r": "0xdb095e6cbf...2133",
      "s": "0x5aa3918399...89b3",
      "v": 27,
      "signature": "0xdb095e6cbf...b31b"
    },
    "reference": "iron-verification-001",
    "metadata": {
      "provider": "iron",
      "purpose": "wallet-verification"
    },
    "wallet": {
      "id": "d236a191-c1d4-423c-a439-54ce6542ca41",
      "name": "Ethereum Master Wallet"
    },
    "blockchain": {
      "name": "ethereum",
      "network": "testnet"
    },
    "confirmed": true,
    "createdAt": "2025-03-02T19:00:52.000Z"
  }
}

Webhook Payload (Transaction Signing)

For transaction signing, the signedTransaction field is a string (not an object). The format depends on the chain.

{
  "event": "signed.success",
  "data": {
    "id": "782942da-48b0-416b-924b-8f657ae637a7",
    "reference": "52TQawmiqYpNiWD2Ks0P",
    "hash": "0xac4c73ca084608ac6b981e54db948dc80c15b4ea3ffd0c9f5781f3af7ad6fe51",
    "status": "SUCCESS",
    "type": "SIGNED",
    "senderAddress": "0xC887a3Cb8E7AbA4A77D7275AD4B242f71cbd5446",
    "recipientAddress": "0xC887a3Cb8E7AbA4A77D7275AD4B242f71cbd5446",
    "signedTransaction": "0x02f87383aa36a763843b9aca008459682f00...",
    "network": "testnet",
    "chainId": 11155111,
    "confirmed": true,
    "wallet": {
      "id": "3f9aca5c-38ee-4e1d-ab67-c084a2e37bb2",
      "name": "Ethereum Wallet"
    },
    "blockchain": {
      "name": "ethereum",
      "symbol": "eth",
      "slug": "ethereum"
    },
    "createdAt": "2026-03-19T13:34:24.937Z"
  }
}

Webhook Payload (Broadcast Success)

After the broadcast queue confirms the transaction on chain, you receive this webhook. The hash field is updated to the on chain transaction hash and confirmed changes to true.

{
  "event": "signed.success",
  "data": {
    "id": "f3efdbaa-a1f8-4365-b3b4-768413c9a92b",
    "reference": "docs-test-broadcast",
    "hash": "5bKNw9RX8aXkrK1VEHg5aPa1xtckpShPyenSRET4mUBXh5uCkWLFV5MhGRi4cMACDJvFn6VfkoKb75Pk4KYw6xtw",
    "status": "SUCCESS",
    "type": "SIGNED",
    "senderAddress": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
    "recipientAddress": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
    "signedTransaction": "AeWpW65y80rSu+TU0CSrcvFNovyDiybKRjSskCpfffAFLM0GIYzx...",
    "network": "testnet",
    "chainId": 103,
    "confirmed": true,
    "wallet": {
      "id": "c72a6f21-6ab5-48ad-9f99-fd90a2d6d311",
      "name": "Solana Testnet Wallet"
    },
    "blockchain": {
      "name": "solana",
      "symbol": "sol",
      "slug": "solana"
    },
    "createdAt": "2026-03-19T13:35:09.921Z"
  }
}

Webhook Payload (Broadcast Failed)

If the broadcast fails permanently after all retry attempts, you receive this webhook. The status is FAILED and confirmed remains false.

{
  "event": "signed.failed",
  "data": {
    "id": "f3efdbaa-a1f8-4365-b3b4-768413c9a92b",
    "reference": "docs-test-broadcast",
    "hash": "5bKNw9RX8aXkrK1VEHg5aPa1xtckpShPyenSRET4mUBX...",
    "status": "FAILED",
    "type": "SIGNED",
    "senderAddress": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
    "recipientAddress": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
    "signedTransaction": "AeWpW65y80rSu+TU0CSrcvFNovyDiybKRjSskCpfffAFLM0GIYzx...",
    "network": "testnet",
    "chainId": 103,
    "confirmed": false,
    "wallet": {
      "id": "c72a6f21-6ab5-48ad-9f99-fd90a2d6d311",
      "name": "Solana Testnet Wallet"
    },
    "blockchain": {
      "name": "solana",
      "symbol": "sol",
      "slug": "solana"
    },
    "createdAt": "2026-03-19T13:35:09.921Z"
  }
}

---

Transaction Signing

Sign a raw, unsigned transaction built externally. You build the transaction using any SDK (ethers.js, TronWeb, Solana web3.js, Jupiter API), then send the serialized unsigned transaction to Blockradar. Blockradar signs it with the wallet’s private key and returns the signed transaction without ever exposing the key to your application.

Supported Blockchains and Formats

Blockchain	transaction field format	How to build
Solana	Base64 of VersionedTransaction.serialize()	Jupiter API /swap response, or @solana/web3.js TransactionMessage
EVM	JSON string of {to, value, data, nonce, chainId, gasLimit, maxFeePerGas, ...}	ethers.js populateTransaction()
Tron	JSON string of TronWeb transaction object {txID, raw_data, raw_data_hex}	tronWeb.transactionBuilder.triggerSmartContract()

Request Parameters

Parameter	Type	Required	Description
transaction	string	Yes	The serialized unsigned transaction. Format depends on the blockchain.
reference	string	No	Your internal tracking ID.
metadata	object	No	Custom key-value pairs stored with the transaction record.

Transaction Signing Example (Solana + Jupiter)

JavaScript

import { Connection, PublicKey, VersionedTransaction } from '@solana/web3.js';

// Step 1: Build the swap transaction via Jupiter API
const quoteResponse = await fetch(
  'https://quote-api.jup.ag/v6/quote?inputMint=SOL&outputMint=USDC&amount=1000000&slippageBps=50'
).then(r => r.json());

const swapResponse = await fetch('https://quote-api.jup.ag/v6/swap', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    quoteResponse,
    userPublicKey: walletAddress, // Your Blockradar wallet's Solana address
    wrapAndUnwrapSol: true,
  })
}).then(r => r.json());

// Step 2: Send the unsigned transaction to Blockradar for signing
const signResponse = await fetch(
  `https://api.blockradar.co/v1/wallets/${walletId}/signing/transaction`,
  {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'x-api-key': apiKey
    },
    body: JSON.stringify({
      transaction: swapResponse.swapTransaction, // Base64 VersionedTransaction
      reference: 'jupiter-swap-001'
    })
  }
).then(r => r.json());

console.log('Signed tx:', signResponse.data.signedTransaction);
console.log('Hash:', signResponse.data.hash);

Transaction Signing Example (EVM)

JavaScript

import { ethers } from 'ethers';

// Step 1: Build the unsigned transaction
const provider = new ethers.providers.JsonRpcProvider('https://rpc.sepolia.org');
const nonce = await provider.getTransactionCount(walletAddress);
const feeData = await provider.getFeeData();

const unsignedTx = JSON.stringify({
  to: '0xRecipientAddress',
  value: ethers.utils.parseEther('0.01').toHexString(),
  nonce,
  chainId: 11155111, // Sepolia
  gasLimit: ethers.utils.hexlify(21000),
  maxFeePerGas: feeData.maxFeePerGas.toHexString(),
  maxPriorityFeePerGas: feeData.maxPriorityFeePerGas.toHexString(),
  type: 2,
});

// Step 2: Send to Blockradar for signing
const signResponse = await fetch(
  `https://api.blockradar.co/v1/wallets/${walletId}/signing/transaction`,
  {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'x-api-key': apiKey
    },
    body: JSON.stringify({
      transaction: unsignedTx,
      reference: 'eth-transfer-001'
    })
  }
).then(r => r.json());

// The signed transaction can be broadcast via any RPC
// await provider.sendTransaction(signResponse.data.signedTransaction);

Sign-Only Response (EVM)

{
  "statusCode": 200,
  "message": "Transaction signed successfully",
  "data": {
    "id": "782942da-48b0-416b-924b-8f657ae637a7",
    "reference": "52TQawmiqYpNiWD2Ks0P",
    "senderAddress": "0xC887a3Cb8E7AbA4A77D7275AD4B242f71cbd5446",
    "recipientAddress": "0xC887a3Cb8E7AbA4A77D7275AD4B242f71cbd5446",
    "hash": "0xac4c73ca084608ac6b981e54db948dc80c15b4ea3ffd0c9f5781f3af7ad6fe51",
    "confirmed": true,
    "status": "SUCCESS",
    "type": "SIGNED",
    "createdChannel": "api",
    "reason": "Transaction signed",
    "network": "testnet",
    "chainId": 11155111,
    "metadata": null,
    "signedTransaction": "0x02f87383aa36a763843b9aca008459682f0082520894000000000000000000000000000000000000dead865af3107a400080c080a0b760...",
    "amount": null,
    "amountUSD": "0.00",
    "fee": null,
    "feeUSD": null,
    "currency": "USD",
    "createdAt": "2026-03-19T13:34:24.937Z",
    "updatedAt": "2026-03-19T13:34:24.937Z",
    "wallet": {
      "id": "3f9aca5c-38ee-4e1d-ab67-c084a2e37bb2",
      "name": "Ethereum Wallet",
      "address": "0xC887a3Cb8E7AbA4A77D7275AD4B242f71cbd5446",
      "isActive": true,
      "status": "ACTIVE",
      "network": "testnet"
    },
    "asset": null,
    "blockchain": {
      "id": "85ffc132-3972-4c9e-99a5-5cf0ccb688bf",
      "name": "ethereum",
      "symbol": "eth",
      "slug": "ethereum",
      "isEvmCompatible": true,
      "tokenStandard": "ERC20"
    },
    "beneficiary": null
  }
}

Sign-Only Response (Solana)

{
  "statusCode": 200,
  "message": "Transaction signed successfully",
  "data": {
    "id": "02f404a5-d13e-4bcf-8ad5-c5f51c04fa49",
    "reference": "qZmQqDiIp9owMzQJcDbv",
    "senderAddress": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
    "recipientAddress": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
    "hash": "TjphHHAzjhRBn8t1qhhTRWpUxvkATBnzeRBB8fonWkYpR1gDh4t99rmgah3hrwoCbD3L9Ex1a7SYjjX2TePio3s",
    "confirmed": true,
    "status": "SUCCESS",
    "type": "SIGNED",
    "createdChannel": "api",
    "reason": "Transaction signed",
    "network": "testnet",
    "chainId": 103,
    "metadata": null,
    "signedTransaction": "ARcO4DT2IYg/wemCZy4iYXVRzlGruYHUTGqIcbWI/uWeWet6MNZKVVvUF4yT5GQjRqrb1QD1TaAoflyXXatxzAaAAQABA...",
    "amount": null,
    "amountUSD": "0.00",
    "fee": null,
    "feeUSD": null,
    "currency": "USD",
    "createdAt": "2026-03-19T13:38:45.326Z",
    "updatedAt": "2026-03-19T13:38:45.326Z",
    "wallet": {
      "id": "c72a6f21-6ab5-48ad-9f99-fd90a2d6d311",
      "name": "Solana Testnet Wallet",
      "address": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
      "isActive": true,
      "status": "ACTIVE",
      "network": "testnet"
    },
    "asset": null,
    "blockchain": {
      "id": "196badf5-380f-4480-ab4a-d0e4304e91f0",
      "name": "solana",
      "symbol": "sol",
      "slug": "solana",
      "isEvmCompatible": false,
      "tokenStandard": null
    },
    "beneficiary": null
  }
}

Sign-Only Response (Tron)

{
  "statusCode": 200,
  "message": "Transaction signed successfully",
  "data": {
    "id": "af44218f-d38b-472b-9834-49f461a20fd4",
    "reference": "J6RugzxXI6cdpeMXrhh",
    "senderAddress": "TMUZSkS3aF1pZxnTokWikUQH7SYt3bNb6G",
    "recipientAddress": "TMUZSkS3aF1pZxnTokWikUQH7SYt3bNb6G",
    "hash": "3180f971f692a78f62050278149d746abd946fbd1797a414f5ad0d5ed45c902b",
    "confirmed": true,
    "status": "SUCCESS",
    "type": "SIGNED",
    "createdChannel": "api",
    "reason": "Transaction signed",
    "network": "testnet",
    "chainId": 3448148188,
    "metadata": null,
    "signedTransaction": "{\"visible\":false,\"txID\":\"3180f971f692a78f...\",\"raw_data\":{\"contract\":[{\"parameter\":{\"value\":{\"to_address\":\"418840e6c55b9ada...\",\"owner_address\":\"417e3682ec8f5b98...\",\"amount\":1000000},\"type_url\":\"type.googleapis.com/protocol.TransferContract\"},\"type\":\"TransferContract\"}],\"ref_block_bytes\":\"513f\",\"ref_block_hash\":\"08c7d5da0ddd12fb\",\"expiration\":1773927585000,\"timestamp\":1773927525000},\"signature\":[\"d5adac23f23414083ef4f93b995a4a18...\"]}",
    "amount": null,
    "amountUSD": "0.00",
    "fee": null,
    "feeUSD": null,
    "currency": "USD",
    "createdAt": "2026-03-19T13:38:47.096Z",
    "updatedAt": "2026-03-19T13:38:47.096Z",
    "wallet": {
      "id": "c4bbebea-6cec-4021-b842-ffead75fd0f1",
      "name": "Tron Wallet",
      "address": "TMUZSkS3aF1pZxnTokWikUQH7SYt3bNb6G",
      "isActive": true,
      "status": "ACTIVE",
      "network": "testnet"
    },
    "asset": null,
    "blockchain": {
      "id": "fa91a922-3838-45f6-8a88-a4c771e1443a",
      "name": "tron",
      "symbol": "trx",
      "slug": "tron",
      "isEvmCompatible": false,
      "tokenStandard": "TRC20"
    },
    "beneficiary": null
  }
}

For transaction signing, signedTransaction is a string, not an object. This is different from message signing where it returns an object with signature components like r, s, v.

signedTransaction Format by Chain

Chain	Type	Format	What to do with it
Solana	string	Base64 encoded bytes of the signed VersionedTransaction	Decode to bytes and pass to connection.sendRawTransaction()
EVM	string	Hex string starting with 0x containing the RLP encoded signed transaction	Pass directly to eth_sendRawTransaction or provider.sendTransaction()
Tron	string	JSON string of the signed transaction object containing a signature array	Parse with JSON.parse() and pass to tronWeb.trx.sendRawTransaction()

hash Field by Chain

Chain	Format	How it is derived
Solana	Base58 string	First signature from the signed transaction
EVM	Hex string starting with 0x	Keccak256 hash of the signed transaction bytes
Tron	Hex string	The txID field from the transaction object, computed during transaction building

---

Transaction Broadcast

Sign and broadcast a raw transaction in one step. Blockradar signs the transaction, then submits it on-chain via a reliable queue with automatic retries. The API returns immediately with PENDING status. You’ll receive a signed.success or signed.failed webhook when the on-chain result is confirmed.

Broadcast requires testnet/mainnet funds in the wallet to pay gas fees. The transaction must be valid and not expired (Solana blockhashes expire in ~90 seconds).

Request

Same parameters as transaction signing:

Parameter	Type	Required	Description
transaction	string	Yes	The serialized unsigned transaction.
reference	string	No	Your internal tracking ID.
metadata	object	No	Custom key-value pairs.

Broadcast Example

JavaScript

// Build the unsigned tx (same as sign-only examples above)
const unsignedTx = swapResponse.swapTransaction; // Jupiter base64 tx

// Sign + broadcast in one call
const broadcastResponse = await fetch(
  `https://api.blockradar.co/v1/wallets/${walletId}/signing/broadcast`,
  {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'x-api-key': apiKey
    },
    body: JSON.stringify({
      transaction: unsignedTx,
      reference: 'jupiter-swap-broadcast-001'
    })
  }
).then(r => r.json());

console.log('Status:', broadcastResponse.data.status); // "PENDING"
console.log('Transaction ID:', broadcastResponse.data.id);
// Wait for webhook: signed.success or signed.failed

Broadcast Response (Solana Example, immediate)

{
  "statusCode": 200,
  "message": "Transaction signed and broadcast initiated",
  "data": {
    "id": "f3efdbaa-a1f8-4365-b3b4-768413c9a92b",
    "reference": "docs-test-broadcast",
    "senderAddress": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
    "recipientAddress": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
    "hash": "5bKNw9RX8aXkrK1VEHg5aPa1xtckpShPyenSRET4mUBXh5uCkWLFV5MhGRi4cMACDJvFn6VfkoKb75Pk4KYw6xtw",
    "confirmed": false,
    "status": "PENDING",
    "type": "SIGNED",
    "createdChannel": "api",
    "reason": "Transaction signed and broadcast",
    "network": "testnet",
    "chainId": 103,
    "metadata": null,
    "signedTransaction": "AeWpW65y80rSu+TU0CSrcvFNovyDiybKRjSskCpfffAFLM0GIYzx...",
    "amount": null,
    "amountUSD": "0.00",
    "fee": null,
    "feeUSD": null,
    "currency": "USD",
    "createdAt": "2026-03-19T13:35:09.921Z",
    "updatedAt": "2026-03-19T13:35:09.921Z",
    "wallet": {
      "id": "c72a6f21-6ab5-48ad-9f99-fd90a2d6d311",
      "name": "Solana Testnet Wallet",
      "address": "HKqZUT3wuyJrsPYmrYPcGduDdjXZTggbLrNsF9WHMvbw",
      "isActive": true,
      "status": "ACTIVE",
      "network": "testnet"
    },
    "asset": null,
    "blockchain": {
      "id": "196badf5-380f-4480-ab4a-d0e4304e91f0",
      "name": "solana",
      "symbol": "sol",
      "slug": "solana",
      "isEvmCompatible": false,
      "tokenStandard": null
    },
    "beneficiary": null
  }
}

Broadcast Lifecycle

The transaction goes through these states:

Status	Meaning
PENDING	Transaction signed, broadcast queued. You receive this in the HTTP response.
SUCCESS	Transaction confirmed on-chain. Webhook signed.success is sent.
FAILED	Broadcast failed after all retries exhausted. Webhook signed.failed is sent.

The broadcast queue retries up to 10 times with 5-minute intervals. For Solana, if the blockhash expires, retries will not help. You’ll need to rebuild the transaction with a fresh blockhash.

---

Complete Flow Example

Here’s a full implementation for signing a message and submitting the signature to a third-party provider:

async function signAndVerifyWithProvider(walletId, providerMessage) {
  const apiKey = process.env.BLOCKRADAR_API_KEY;
  const baseUrl = 'https://api.blockradar.co/v1';

  // Step 1: Sign the message
  const signResponse = await fetch(
    `${baseUrl}/wallets/${walletId}/signing/message`,
    {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'x-api-key': apiKey
      },
      body: JSON.stringify({
        message: providerMessage,
        reference: `provider-verify-${Date.now()}`
      })
    }
  ).then(r => r.json());

  if (signResponse.statusCode !== 200) {
    throw new Error(`Signing failed: ${signResponse.message}`);
  }

  const { hash, senderAddress } = signResponse.data;

  // Step 2: Submit the signature to the third-party provider
  // The provider can verify the signature matches the wallet address
  // without accessing your private keys
  return {
    address: senderAddress,
    signature: hash,
    message: providerMessage
  };
}

// Usage
signAndVerifyWithProvider(
  'wallet-uuid',
  'I authorize Iron to manage assets on my behalf.'
);

---

Error Responses

Wallet Not Found

{
  "message": "Wallet not found",
  "statusCode": 404
}

The walletId does not exist or does not belong to your business.

Address Not Found

{
  "message": "Address not found",
  "statusCode": 404
}

The addressId does not exist or is not associated with the specified wallet.

Unsupported Blockchain (Typed Data)

{
  "message": "Typed data signing is only supported for EVM blockchains",
  "statusCode": 400
}

Typed data signing (EIP-712) is only available on EVM-compatible chains. Use message signing for Tron and Solana.

Chain ID Mismatch

{
  "message": "Chain ID mismatch",
  "statusCode": 400
}

The chainId in your typed data domain object does not match the wallet’s blockchain network.

Signature Verification Failed

{
  "message": "Signature verification failed",
  "statusCode": 400
}

Internal round-trip verification failed. This indicates a system error. Please contact support.

Invalid Transaction Format (Solana)

{
  "message": "Invalid transaction format: expected a base64-encoded Solana VersionedTransaction",
  "statusCode": 400
}

The transaction field is not valid base64, or the decoded bytes are not a valid Solana VersionedTransaction.

Invalid Transaction Format (EVM/Tron)

{
  "message": "Invalid transaction format: expected a JSON string",
  "statusCode": 400
}

The transaction field is not valid JSON. EVM and Tron transactions must be JSON-stringified objects.

---

Best Practices

Security

• Use references: Track signing operations with unique reference IDs for audit trails and idempotency
• Verify the message: Before signing, confirm the message content matches what the third-party service expects
• Limit message length: Messages are capped at 4,096 characters. Keep messages concise and specific

Integration

• No gas fees: Signing operations are off-chain and do not require native token balance
• Immediate response: Signatures are generated synchronously. No polling or webhook waiting required for the signature itself
• Listen for webhooks: Use webhooks to maintain an audit trail of all signing events

Typed Data

• Match chain IDs: The chainId in your domain must match the wallet’s network. Use sandbox (testnet) chain IDs for testing and production (mainnet) chain IDs for live operations
• Check the contract: The verifyingContract must be the contract that will verify the signature on-chain

Transaction Signing

• Build the transaction with the correct sender: The unsigned transaction must use the wallet or child address public key as the fee payer (Solana) or sender (EVM/Tron). If the key does not match, signing will fail.
• Solana blockhashes expire quickly: Solana blockhashes are valid for about 60 to 90 seconds. Build the transaction and call the signing endpoint promptly. If using broadcast, the queue retries will not help once the blockhash expires.
• EVM nonce management: Set the nonce correctly. If the nonce is already used, the broadcast will fail. Query the nonce from the chain immediately before building the transaction.
• Tron expiration: Tron transactions have a 24 hour expiration window set during building. This gives plenty of time for signing and broadcast.
• Sign only vs broadcast: Use /signing/transaction when you want to broadcast the transaction yourself or through another service. Use /signing/broadcast when you want Blockradar to handle submission with automatic retries.

---

API Reference

Master Wallet Endpoints

Endpoint	Description
Sign Message	Sign a plain text message
Sign Typed Data	Sign EIP-712 structured data
Sign Transaction	Sign a raw transaction
Broadcast Transaction	Sign and broadcast a raw transaction

Child Address Endpoints

Endpoint	Description
Sign Message	Sign a plain text message from a child address
Sign Typed Data	Sign EIP-712 structured data from a child address
Sign Transaction	Sign a raw transaction from a child address
Broadcast Transaction	Sign and broadcast a raw transaction from a child address