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WEBHOOK
walletTransactionReplaced
{
  "transaction_hash": "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
  "address": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
  "network": "base",
  "replaced_at": "2025-06-01T10:03:00Z"
}

Authorizations

​
X-Hook0-Signature
string
header
required

HMAC-SHA256 signature of the raw request body, computed using your webhook secret. Webhook receivers should always verify this header before processing the event. The header value is hex-encoded and prefixed by the algorithm and timestamp, e.g. t=1700000000,v1=abc123... (refer to the Webhook Security docs for the exact verification algorithm).

This scheme applies to webhook delivery (outbound POSTs from CDP to your endpoint), not to inbound CDP API requests.

Body

application/json

The wallet.transaction.replaced webhook event payload.

Delivered when a pending transaction is replaced (e.g. a fee bump). EVM-only. The payload is one of three EVM wallet-type variants: API Key Wallet, User Wallet, or User Wallet (Delegated Signing).

​
transaction_hash
string
required

The onchain transaction hash of the replaced transaction.

Example:

"0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef"

​
address
string
required

The EVM wallet address whose transaction was replaced.

Required string length: 1 - 128
Pattern: ^0x[0-9a-fA-F]{40}$
Example:

"0x742d35Cc6634C0532925a3b844Bc454e4438f44e"

​
network
enum<string>
required

The blockchain network identifier.

Available options:
base,
ethereum,
solana,
aptos,
arbitrum,
arbitrum-sepolia,
optimism,
polygon,
world,
world-sepolia
Example:

"base"

​
replaced_at
string<date-time>
required

When the transaction was replaced (ISO 8601 format).

Example:

"2025-06-01T10:03:00Z"

Response

Webhook received and processed successfully.