Receive and verify Favro webhooks. Use when setting up Favro webhook handlers, debugging X-Favro-Webhook signature verification, accepting the setup ping, or handling card events (card.created, card.committed, card.moved, card.updated, card.deleted) and comment events (comment.created, comment.updated, comment.deleted). Note: Favro does NOT use Standard Webhooks — the signature is base64(HMAC-SHA1(secret, payloadId + the URL you registered)), signed over the payloadId concatenated with the target URL, NOT the raw request body.
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Receive and verify Favro webhooks. Use when setting up Favro webhook handlers, debugging X-Favro-Webhook signature verification, accepting the setup ping, or handling card events (card.created, card.committed, card.moved, card.updated, card.deleted) and comment events (comment.created, comment.updated, comment.deleted). Note: Favro does NOT use Standard Webhooks — the signature is base64(HMAC-SHA1(secret, payloadId + the URL you registered)), signed over the payloadId concatenated with the target URL, NOT the raw request body.
The header is a base64 digest of an HMAC-SHA1 hash. The hashed content is the
concatenation of the payloadId and the URL exactly as it was provided during
webhook creation. The key used to sign this text is the secret you entered when
setting up the webhook.
So verification requires three inputs — and the body is not one of them:
X-Favro-Webhook = base64( HMAC-SHA1( key = secret, message = payloadId + webhookUrl ) )
└─ from body ─┘ └─ from config ─┘
Two consequences drive everything below:
You must know the exact URL you registered. The webhookUrl in the HMAC is
the postToUrl you gave Favro verbatim — same scheme, host, path, trailing
slash, and query string. Store it as an env var (FAVRO_WEBHOOK_URL) and keep
it byte-identical to what you registered, or every signature will mismatch.
The payloadId comes from the JSON body. Every delivery (including the
setup ping) carries a top-level payloadId string. Parse it out, concatenate
payloadId + webhookUrl, and HMAC that — not the body bytes.
Favro ──POST {"payloadId":"…","action":"…", …}──▶ your endpoint
X-Favro-Webhook: <base64 HMAC-SHA1> │ expected = base64(HMAC-SHA1(secret, payloadId + FAVRO_WEBHOOK_URL))
▼ timing-safe compare to header
valid? → dispatch on action → 200
ping? → 200 (validates the webhook)
Verification (core)
Sign payloadId + webhookUrl with your webhook secret using HMAC-SHA1,
base64-encode, and compare to the X-Favro-Webhook header with a timing-safe
compare. The signed message is not the raw body — do not HMAC the body.
const crypto = require('crypto');
// X-Favro-Webhook = base64( HMAC-SHA1( secret, payloadId + webhookUrl ) )// payloadId comes from the JSON body; webhookUrl is the URL you registered, verbatim.functionverifyFavroWebhook(payloadId, webhookUrl, secret, signature) {
if (!payloadId || !webhookUrl || !secret || !signature) returnfalse;
const expected = crypto
.createHmac('sha1', secret)
.update(payloadId + webhookUrl, 'utf8')
.digest('base64');
try {
return crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(signature));
} catch {
returnfalse; // different lengths => invalid
}
}
There is no official Favro SDK, so verification is manual in every language (the
community Node package @bscotch/bravo
implements the same scheme). Parse the body only to read payloadId; the
signature does not cover the body, so re-serialization is not a concern here.
For complete handlers with route wiring, event dispatch, ping handling, and tests, see:
When a webhook is created, Favro sends a ping to validate the endpoint. Your
handler must return a 2xx or the webhook stays unvalidated. The ping carries a
payloadId, so it is signed with the same scheme — verify it like any other event
and return 200:
If your ping fails verification during setup, the cause is almost always that
FAVRO_WEBHOOK_URL does not exactly match the URL you registered.
Common Event Types
Every payload has a top-level action string. The object type is determined by
which object is present (card, comment, or hook for the ping), so handlers
dispatch on the combined <type>.<action> key below.
Event
action
Fires When
ping
ping
Webhook is created — validate the endpoint (return 2xx)
card.created
created
A card is created
card.committed
committed
A card is committed (moved out of a sheet/backlog into a board)
card.moved
moved
A card moves between columns/boards
card.updated
updated
A card's fields change
card.deleted
deleted
A card is deleted
comment.created
created
A comment is added
comment.updated
updated
A comment is edited
comment.deleted
deleted
A comment is deleted
Note: UI-automation-triggered webhooks send partial data with no pre-update
state. Treat fields as possibly-absent and fetch the full card from the Favro
API when you need the complete record. See references/overview.md.
Environment Variables
FAVRO_WEBHOOK_SECRET=your_webhook_secret # the secret you entered when creating the webhook
FAVRO_WEBHOOK_URL=https://example.com/webhooks/favro # the postToUrl you registered, VERBATIM
FAVRO_WEBHOOK_URL is part of the signed message, so it must be byte-identical to
the URL Favro has on file for this webhook. See references/setup.md.
Local Development
# Start tunnel (no account needed) — forwards to your local handler
npx hookdeck-cli listen 3000 favro --path /webhooks/favro
Register the resulting public URL as the postToUrl when you create the webhook,
and set FAVRO_WEBHOOK_URL to that exact same URL.
We recommend installing the webhook-handler-patterns skill alongside this one for handler sequence, idempotency, error handling, and retry logic. Key references (open on GitHub):
hookdeck-event-gateway - Webhook infrastructure that replaces your queue — guaranteed delivery, automatic retries, replay, rate limiting, and observability for your webhook handlers
