# Add a webhook endpoint

> Page: https://docs.flung.dev/reference/api/post-v1-webhook-endpoints. Index of every page: https://docs.flung.dev/llms.txt

Flung POSTs each subscribed event to the URL, signed to the Standard Webhooks spec with the returned secret, and retries failures with backoff for about 15 hours.

`POST /v1/webhook-endpoints`

## TL;DR

| Question | Answer |
|---|---|
| What does it do? | Add a webhook endpoint. |
| What does it need? | An API key or an OAuth access token. |
| What does it take? | A JSON body with the fields below, and `idempotency-key` in a header. |
| What does it return? | Status 201 with a body of type [`CreatedWebhookEndpoint`](https://docs.flung.dev/reference/api/schemas.md#createdwebhookendpoint). |
| In the SDK? | `flung.webhookEndpoints.create()` |
| What can go wrong? | `401` Missing, unknown, revoked or expired API key; `422` The request failed validation; `429` Too many requests for this credential; wait for `retry-after` seconds. Every failure has the same [error shape](https://docs.flung.dev/reference/api/errors.md). |

## Example

**curl**

```bash
curl -X POST 'https://api.flung.dev/v1/webhook-endpoints' \
  --header "Authorization: Bearer $FLUNG_API_KEY" \
  --header 'Content-Type: application/json' \
  --header "Idempotency-Key: $(uuidgen)" \
  --data '{
  "url": "https://example.com/webhooks/flung",
  "events": [
    "post.published",
    "post.failed"
  ]
}'
```

**TypeScript**

```ts
import { Flung } from '@flung.dev/sdk'

const flung = new Flung({ apiKey: process.env.FLUNG_API_KEY! })
const result = await flung.webhookEndpoints.create({
  url: 'https://example.com/webhooks/flung',
  events: [
    'post.published',
    'post.failed',
  ],
})
```

**fetch**

```js
const response = await fetch('https://api.flung.dev/v1/webhook-endpoints', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${process.env.FLUNG_API_KEY}`,
    'Content-Type': 'application/json',
    'Idempotency-Key': crypto.randomUUID(),
  },
  body: JSON.stringify({
    url: 'https://example.com/webhooks/flung',
    events: [
      'post.published',
      'post.failed',
    ],
  }),
})
if (!response.ok) throw new Error((await response.json()).error.message)
const result = await response.json()
```

A successful answer looks like this:

```json
{
  "id": "whe_aaaaaaaaaaaaaaaaaaaaaaaa",
  "url": "string",
  "events": [
    "string"
  ],
  "enabled": true,
  "createdAt": "2026-11-01T09:00:00.000Z",
  "secret": "whsec_MfKQ9r8GKYqrTwjUPD8ILPZIo2LaLaSw"
}
```

## Header parameters

| Field | Type | Required | Description |
|---|---|---|---|
| `idempotency-key` | `string` | no | Any unique string, such as a UUID. A retry with the same key and body within 24 hours gets the first answer instead of running again. |

## Request body

The body has the type an object, with the fields below.

| Field | Type | Required | Description |
|---|---|---|---|
| `url` | `string` | yes | at most 2048 characters. |
| `events` | `WebhookEvent[]` | yes |  |

## Responses

| Status | Meaning | Body |
|---|---|---|
| 201 | The endpoint, with its signing secret. | [`CreatedWebhookEndpoint`](https://docs.flung.dev/reference/api/schemas.md#createdwebhookendpoint) |
| 401 | Missing, unknown, revoked or expired API key. | [`Error`](https://docs.flung.dev/reference/api/schemas.md#error) |
| 422 | The request failed validation. | [`Error`](https://docs.flung.dev/reference/api/schemas.md#error) |
| 429 | Too many requests for this credential; wait for `retry-after` seconds. | [`Error`](https://docs.flung.dev/reference/api/schemas.md#error) |

## Response body

A 201 answer has the type [`CreatedWebhookEndpoint`](https://docs.flung.dev/reference/api/schemas.md#createdwebhookendpoint).

| Field | Type | Required | Description |
|---|---|---|---|
| `id` | `string` | yes |  |
| `url` | `string` | yes |  |
| `events` | `string[]` | yes |  |
| `enabled` | `boolean` | yes |  |
| `createdAt` | `string` | yes |  |
| `secret` | `string` | yes | The signing secret (Standard Webhooks, `whsec_...`). Shown only in this response; store it now. |

## See also

| Doc | Why |
|---|---|
| [API reference](https://docs.flung.dev/reference/api.md) | Every endpoint |
| [Schemas](https://docs.flung.dev/reference/api/schemas.md) | Every request and response type |
| [Errors](https://docs.flung.dev/reference/api/errors.md) | Every error code and what to do about it |