Implement a Fireblocks webhook handler to detect and respond to compliance-flagged transaction events

Steps

1. Register a webhook endpoint in the Fireblocks console under Settings > Webhooks; provide an HTTPS URL that returns HTTP 200 within 5 seconds
2. Verify incoming webhooks: Fireblocks signs payloads with an RSA private key; retrieve the public key from the Fireblocks console and verify the X-Fireblocks-Signature header against the SHA-512 hash of the raw body
3. Subscribe to TRANSACTION_STATUS_UPDATED events; parse the data.status field and map REJECTED, FAILED, BLOCKED (TAP-blocked) statuses to compliance workflow triggers
4. For BLOCKED transactions (blocked by TAP policy), extract data.subStatus and data.txHash to identify the transaction; route to your compliance queue with the Fireblocks txId for manual review
5. For COMPLETED transactions, extract data.destinationAddress and data.assetId and submit to Chainalysis KYT or TRM Labs for post-broadcast monitoring using the on-chain txHash
6. Implement exponential backoff retry logic in your webhook handler; if your endpoint returns non-200, Fireblocks retries with increasing delays — ensure idempotent processing using the txId as a deduplication key