---
title: "set_thumbnail"
description: "Set or replace the custom thumbnail of a post already on the platform. imageUrl: public https JPEG/PNG (YouTube: ≤ 2 MB, 1280×720, verified channel). For a post still 'scheduled', use update_post with metadata.thumbnailUrl. Needs the **publish** permission. Also available as the MCP tool `set_thumbnail`."
---

> Documentation Index
> Fetch the complete documentation index at: https://docs.mixetape.com/llms.txt
> Use this file to discover all available pages before exploring further.

Path: mixetape API › publish

`POST /api/v1/tools/set_thumbnail`

Set or replace the custom thumbnail of a post already on the platform. imageUrl: public https JPEG/PNG (YouTube: ≤ 2 MB, 1280×720, verified channel). For a post still 'scheduled', use update_post with metadata.thumbnailUrl. Needs the **publish** permission. Also available as the MCP tool `set_thumbnail`.

## Authentication

- `apiKey`, http, header `Authorization`

## Request body

_Required._

- `set_thumbnail.id` (string, required) — mixetape post id (list_posts)
- `set_thumbnail.imageUrl` (string, required)

## Example request

```json
{
  "id": "string",
  "imageUrl": "string"
}
```

## Code samples

### cURL

```curl
curl --request POST \
  --url https://mixetape.com/api/v1/tools/set_thumbnail \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": "string",
  "imageUrl": "string"
}
'
```

### TypeScript

```typescript
const url = 'https://mixetape.com/api/v1/tools/set_thumbnail';
const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json', Authorization: 'Bearer <token>'},
  body: JSON.stringify({id: 'string', imageUrl: 'string'})
};

fetch(url, options)
  .then(res => res.json())
  .then(json => console.log(json))
  .catch(err => console.error(err));
```

### Python

```python
import requests

url = "https://mixetape.com/api/v1/tools/set_thumbnail"

payload = {
    "id": "string",
    "imageUrl": "string"
}
headers = {
    "Content-Type": "application/json",
    "Authorization": "Bearer <token>"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)
```

## Responses

### 200

The tool's result.

#### Example

```json
{
  "result": null
}
```

- `set_thumbnail.response.200.result` (unknown, required) — What the tool returns

### 400

The request is invalid; `error` says why.

#### Example

```json
{
  "error": "string"
}
```

- `set_thumbnail.response.400.error` (string, required) — What went wrong, in plain words

### 401

No valid API key.

#### Example

```json
{
  "error": "string"
}
```

- `set_thumbnail.response.401.error` (string, required) — What went wrong, in plain words

### 403

The key lacks the permission this needs.

#### Example

```json
{
  "error": "string"
}
```

- `set_thumbnail.response.403.error` (string, required) — What went wrong, in plain words

### 404

Not found, or not yours.

#### Example

```json
{
  "error": "string"
}
```

- `set_thumbnail.response.404.error` (string, required) — What went wrong, in plain words


Source: https://docs.mixetape.com/api/publish/set_thumbnail/index.md