Agent skill

Fireblocks Webhooks Skill

Receive and verify Fireblocks webhooks. Use when setting up Fireblocks webhook handlers, debugging Fireblocks-Webhook-Signature verification (detached JWS / RS512 / JWKS), or handling digital-asset events like transaction.created, transaction.status.updated, or transaction.approval_status.updated.

Install this skill

npx skills add hookdeck/webhook-skills --skill fireblocks-webhooks

When to Use This Skill

How do I receive Fireblocks webhooks?
How do I verify the Fireblocks-Webhook-Signature header?
Why is my Fireblocks webhook signature verification failing?
How do I handle transaction.created or transaction.status.updated events?
How do I validate a Fireblocks detached JWS (RS512) against the JWKS endpoint?

Verification (core)

Fireblocks Webhooks v2 signs every request with a detached JWS (RS512, RSA + SHA-512) in the Fireblocks-Webhook-Signature header. The header is a compact JWS with an empty payload segment (<protected-header>..<signature>). To verify, reinsert the raw request body (base64url-encoded) as the payload, then verify against the auto-rotated regional JWKS (https://keys.fireblocks.io/.well-known/jwks.json). Use the raw body bytes — never JSON.parse first.

import { createRemoteJWKSet, compactVerify } from 'jose';

const JWKS = createRemoteJWKSet(
  new URL('https://keys.fireblocks.io/.well-known/jwks.json')
);

// signatureHeader = value of the `Fireblocks-Webhook-Signature` header (detached JWS)
export async function verifyFireblocksWebhook(rawBody, signatureHeader) {
  const [header, , signature] = signatureHeader.split('.');   // header .. signature
  const payload = Buffer.from(rawBody).toString('base64url');  // raw body as JWS payload
  const fullJws = `${header}.${payload}.${signature}`;
  const { payload: verified } = await compactVerify(fullJws, JWKS, {
    algorithms: ['RS512'],                                     // pin alg (no alg confusion)
  });
  return JSON.parse(Buffer.from(verified).toString('utf8'));   // { id, eventType, data, ... }
}

For complete handlers with route wiring, event dispatch, and tests, see:
examples/express/
examples/nextjs/
examples/fastapi/

Legacy (Webhooks v1): the older Fireblocks-Signature header (base64 RSA PKCS#1 v1.5 over the SHA-512 hash of the raw body, verified against a static per-environment PEM key) reached its migration deadline on March 20, 2026. New integrations should use the v2 JWKS scheme above. See references/verification.md for the legacy path.

Common Event Types

Event names are dotted lowercase (v2). The event type is in the eventType field; the resource lives in data.

Event	Description
`transaction.created`	A new transaction was created
`transaction.status.updated`	The transaction's primary status changed
`transaction.approval_status.updated`	The transaction's approval/authorization status changed
`transaction.network_records.processing_completed`	Network-level (on-chain) processing completed
`transaction.alert.stuck_confirming`	An EVM transaction is stuck `CONFIRMING` due to low fees

Other categories (vault_account.*, whitelist.*, tokenization.*, network_connection.*) follow the same envelope. See references/overview.md and the transaction event types.

Environment Variables

# Selects the regional JWKS endpoint: production | eu | eu2 | sandbox
FIREBLOCKS_WEBHOOK_ENV=production
# Optional: override the JWKS URL entirely (advanced / self-testing)
# FIREBLOCKS_JWKS_URL=https://keys.fireblocks.io/.well-known/jwks.json

No shared secret is needed — verification uses Fireblocks' public JWKS keys.

Local Development

# Start tunnel (no account needed)
npx hookdeck-cli listen 3000 fireblocks --path /webhooks/fireblocks

Reference Materials

references/overview.md - Fireblocks webhook concepts and event types
references/setup.md - Configure webhooks in the Fireblocks Console / Webhooks v2 API
references/verification.md - Detached JWS / JWKS verification details and gotchas