> For the complete documentation index, see [llms.txt](https://black-sheep-finance.gitbook.io/black-sheep-finance-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://black-sheep-finance.gitbook.io/black-sheep-finance-docs/webhooks/overview.md).

# Overview

Webhooks are how Black Sheep tells your systems that something happened. Every state change — pending approval, sent transaction, blocked transaction — can be POSTed to one or more endpoints you configure.

## Why use them

* **Approvals in Slack** — `approval.pending` → Slack channel → on-call clicks Approve.
* **Bookkeeping** — `tx.sent` → your accounting service / data warehouse.
* **Security** — `tx.blocked` → SIEM / Sentry / PagerDuty.
* **Customer notifications** — `tx.sent` → email your customer that their automation paid a vendor.

## Setup

1. **Dashboard → Webhooks → Add endpoint**.
2. Enter the URL, pick a **format** (`JSON` or `Slack`), select events.
3. Copy the **signing secret** — used to verify HMAC signatures.
4. Save. A test event is delivered immediately.

## Delivery guarantees

* **At-least-once.** A successful delivery is any 2xx response within 10 seconds.
* **Retries**: up to 6 attempts with exponential backoff (0s, 30s, 2m, 10m, 1h, 6h).
* **Ordering**: best-effort, not strict — design handlers to be idempotent on `event_id`.

## Format

JSON format:

```http
POST https://your-app.com/hooks/blacksheep
Content-Type: application/json
X-BlackSheep-Event: approval.pending
X-BlackSheep-Signature: sha256=<hex>
X-BlackSheep-Delivery: <uuid>

{
  "event": "approval.pending",
  "event_id": "evt_...",
  "timestamp": "2026-06-02T18:24:11Z",
  "data": { ... }
}
```

See [Event types](/black-sheep-finance-docs/webhooks/events.md), [Signature verification](/black-sheep-finance-docs/webhooks/signatures.md), [Slack format](/black-sheep-finance-docs/webhooks/slack.md), and [Delivery logs](/black-sheep-finance-docs/webhooks/delivery.md).


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