---
title: "FLUX 3 Max"
description: "FLUX 3 Max is the Black Forest Labs video model. It makes video from text, or from a first frame with an optional last frame. It makes 720p or 1080p video with sound, in any whole length from 5 to 20 seconds."
url: https://docs.roasos.com/models/video/flux-3-max
---

# FLUX 3 Max

<Callout>
  Family 

  `video`

   · model 

  `flux-3-max`

   · catalog 

  `model-catalog@2026-10-06.v5`

   · pricing 

  `customer-pricing@2026-11-05.v15`

  .
</Callout>

## Endpoint

```http
POST https://api.roasos.com/v1/video/flux-3-max
```

Send your API key as a bearer token. The key needs the scope `api:write`. Every paid request also needs an `Idempotency-Key` header.

The envelope fields `quote_only`, `quote_id`, `webhook_url` and `wait_timeout_seconds` behave the same on each model endpoint. Refer to [Jobs](/concepts/jobs) and [Quotes and credits](/concepts/quotes-and-credits).

## Good at

Use FLUX 3 Max for long single takes: product hero moves, b-roll and scene clips. `end_image_url` sets the last frame after a first frame, so the shot lands on an exact end card. Sound is on by default. Set `generate_audio` to false when you add your own track. The price does not change. FLUX 3 Max has no reference input. For a person or a product from reference images, use Kling 4.0 or Seedance 2.5.

## Pricing

The unit is one **clip**. Pricing key: `flux-3-max`.

| Request            | Credits |
| ------------------ | ------- |
| `5s_720p`          | 11      |
| `13s_720p`         | 27      |
| `20s_720p`         | 41      |
| `5s_720p_no_audio` | 11      |

The credits come from the roasOS pricing table. No other field changes the price. To get the exact price of your request, send it with `quote_only: true` first.

## Modes

* `text-to-video`
* `image-to-video`

roasOS selects the mode from the media fields of your request. You do not send a mode.

Provider endpoints: `blackforestlabs/flux-3-max/image-to-video` · `blackforestlabs/flux-3-max/text-to-video`.

## Request fields

| Field                     | Type         | Required | Default | Rule                                                                                      |
| ------------------------- | ------------ | -------- | ------- | ----------------------------------------------------------------------------------------- |
| `aspect_ratio`            | enum         | no       | `16:9`  | `auto`, `21:9`, `16:9`, `4:3`, `1:1`, `3:4`, `9:16`                                       |
| `duration_seconds`        | integer enum | no       | `5`     | `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15`, `16`, `17`, `18`, `19`, `20` |
| `end_image_url`           | string       | no       | —       | https URL; ≤ 4,096 characters; only in `image-to-video`                                   |
| `extend_of_generation_id` | string       | no       | —       | UUID                                                                                      |
| `generate_audio`          | boolean      | no       | `true`  | —                                                                                         |
| `image_url`               | string       | no       | —       | https URL; ≤ 4,096 characters; only in `image-to-video`                                   |
| `mode`                    | enum         | no       | —       | `text-to-video`, `image-to-video`                                                         |
| `prompt`                  | string       | yes      | —       | ≥ 1 character; ≤ 10,000 characters                                                        |
| `quote_id`                | string       | no       | —       | UUID                                                                                      |
| `quote_only`              | boolean      | no       | `false` | —                                                                                         |
| `resolution`              | enum         | no       | `720p`  | `720p`, `1080p`                                                                           |
| `scene_id`                | string       | no       | —       | UUID                                                                                      |
| `seed`                    | integer      | no       | —       | 0–2147483647                                                                              |
| `wait_timeout_seconds`    | integer      | no       | `0`     | 0–60                                                                                      |
| `webhook_url`             | string       | no       | —       | https URL; ≤ 4,096 characters                                                             |

The schema is strict. A field that is not in this table gets `400 unsupported_option`. The field names are the roasOS role names. One role has one name in every family.

## Media

This endpoint accepts these media roles:

* `image_url` — first frame (or the single source image)
* `end_image_url` — last frame
* `scene_id` — first frame — a scene this workspace owns

| Role            | Items | Maximum size | Content types                           | Duration |
| --------------- | ----- | ------------ | --------------------------------------- | -------- |
| `end_image_url` | ≤ 1   | 10 MB        | `image/jpeg`, `image/png`, `image/webp` | —        |
| `image_url`     | ≤ 1   | 10 MB        | `image/jpeg`, `image/png`, `image/webp` | —        |

Every other role is refused: `avatar_id`, `elements`, `product_id`, `product_images`, `references`, `reference_images`, `scene_image`, `video_urls`, `video_url`, `audio_urls`, `audio_url`, `voice_id`. A refused role gets `400 unsupported_option`.

<Callout>
  Each media URL must be an immutable object on 

  `https://cdn.roasos.com`

   that your workspace owns. Any other URL gets 

  `400 reference_media_not_workspace_owned`

  . Refer to 

  [Reference media and uploads](/concepts/reference-media)

   to learn how to put a file there.
</Callout>

## Prompt

Limit 10,000 characters. The model expands the prompt before it makes the video.

* Write one clear prompt: subject, action, setting, camera and light.
* Describe a long take as one continuous action with one camera move.
* In image-to-video, describe the motion only.
* Direct the sound, or the model makes its own.

## Not exposed

These catalog entries describe omitted inputs, pinned values and source constraints. They do not imply that the provider accepts every listed field.

* `reasoning_level` — pinned to `"high", the provider default (the model expands the prompt)`.
* `keyframes` — not accepted by this public endpoint.
* `references` — not accepted by this public endpoint.
* `avatar_id` — not accepted by this public endpoint.
* `product_id` — not accepted by this public endpoint.
* `video_urls` — not accepted by this public endpoint.
* `audio_urls` — not accepted by this public endpoint.
* `audio_url` — not accepted by this public endpoint.
* `negative_prompt` — not accepted by this public endpoint.
* `cfg_scale` — not accepted by this public endpoint.
* `shot_type` — not accepted by this public endpoint.
* `multi_prompt` — not accepted by this public endpoint.

## Result

The result kind is `video`. Always present: `url`.

```json
{
  "data": {
    "id": "gen_…",
    "kind": "video",
    "model": "flux-3-max",
    "status": "completed",
    "result": {
      "url": "https://cdn.roasos.com/workspaces/ws_01/result"
    }
  }
}
```

The files are immutable objects on `https://cdn.roasos.com`. A result URL is a valid media input for your next request.

## Example

The three steps are always the same: quote, run, poll.

<CodeBlockTabs defaultValue="cURL">
  <CodeBlockTabsList>
    <CodeBlockTabsTrigger value="cURL">
      cURL
    </CodeBlockTabsTrigger>

    <CodeBlockTabsTrigger value="JavaScript">
      JavaScript
    </CodeBlockTabsTrigger>

    <CodeBlockTabsTrigger value="Python">
      Python
    </CodeBlockTabsTrigger>
  </CodeBlockTabsList>

  <CodeBlockTab value="cURL">
    ```bash
    # 1. Quote. Nothing is spent.
    curl -X POST https://api.roasos.com/v1/video/flux-3-max \
      -H "Authorization: Bearer roasos_sk_live_..." \
      -H "Idempotency-Key: 0f1c9e2a-flux-3-max-0001" \
      -H "Content-Type: application/json" \
      -d '{"quote_only":true,"prompt":"A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."}'
    # 200 { "data": { "kind": "quote", "quote_id": "q_7Hk...", "credits": 11, "expires_at": "...",
    #        "confirmation": { "model": "flux-3-max", "example": "5s_720p" } } }

    # 2. Run. Same body, same Idempotency-Key, quote_id in place of quote_only.
    curl -X POST https://api.roasos.com/v1/video/flux-3-max \
      -H "Authorization: Bearer roasos_sk_live_..." \
      -H "Idempotency-Key: 0f1c9e2a-flux-3-max-0001" \
      -H "Content-Type: application/json" \
      -d '{"quote_id":"q_7Hk...","prompt":"A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."}'
    # 201 { "data": { "id": "gen_...", "status": "queued", "credits_reserved": 11 } }

    # 3. Poll, then read the result.
    curl https://api.roasos.com/v1/jobs/gen_.../status -H "Authorization: Bearer roasos_sk_live_..."
    curl https://api.roasos.com/v1/jobs/gen_.../result -H "Authorization: Bearer roasos_sk_live_..."
    ```
  </CodeBlockTab>

  <CodeBlockTab value="JavaScript">
    ```javascript
    const key = process.env.ROASOS_API_KEY;
    const url = "https://api.roasos.com/v1/video/flux-3-max";
    const idempotencyKey = "0f1c9e2a-flux-3-max-0001";
    const input = {
      "prompt": "A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."
    };

    const post = (payload) =>
      fetch(url, {
        method: "POST",
        headers: {
          Authorization: `Bearer ${key}`,
          "Idempotency-Key": idempotencyKey,
          "Content-Type": "application/json",
        },
        body: JSON.stringify(payload),
      }).then((response) => response.json());

    // 1. Quote. Nothing is spent.
    const quote = await post({ quote_only: true, ...input });
    console.log(quote.data.credits);

    // 2. Run.
    const job = await post({ quote_id: quote.data.quote_id, ...input });

    // 3. Poll, then read the result.
    let status = "queued";
    while (status !== "completed" && status !== "failed" && status !== "canceled") {
      await new Promise((done) => setTimeout(done, 3000));
      const poll = await fetch(`${url.split("/v1")[0]}/v1/jobs/${job.data.id}/status`, {
        headers: { Authorization: `Bearer ${key}` },
      }).then((response) => response.json());
      status = poll.data.status;
    }

    const result = await fetch(`${url.split("/v1")[0]}/v1/jobs/${job.data.id}/result`, {
      headers: { Authorization: `Bearer ${key}` },
    }).then((response) => response.json());
    console.log(result.data.result);
    ```
  </CodeBlockTab>

  <CodeBlockTab value="Python">
    ```python
    import os, time, requests

    key = os.environ["ROASOS_API_KEY"]
    url = "https://api.roasos.com/v1/video/flux-3-max"
    headers = {
        "Authorization": f"Bearer {key}",
        "Idempotency-Key": "0f1c9e2a-flux-3-max-0001",
    }
    payload = {
        "prompt": "A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."
    }

    # 1. Quote. Nothing is spent.
    quote = requests.post(url, headers=headers, json={"quote_only": True, **payload}).json()
    print(quote["data"]["credits"])

    # 2. Run.
    job = requests.post(url, headers=headers, json={"quote_id": quote["data"]["quote_id"], **payload}).json()
    job_id = job["data"]["id"]

    # 3. Poll, then read the result.
    jobs = "https://api.roasos.com/v1/jobs"
    status = "queued"
    while status not in ("completed", "failed", "canceled"):
        time.sleep(3)
        status = requests.get(f"{jobs}/{job_id}/status", headers=headers).json()["data"]["status"]

    result = requests.get(f"{jobs}/{job_id}/result", headers=headers).json()
    print(result["data"]["result"])
    ```
  </CodeBlockTab>
</CodeBlockTabs>

## The deprecated path

`POST /v1/generations` still reaches this model for one minor version. It is deprecated. This is how it maps:

`POST /v1/video/flux-3-max` with `prompt`, `image_url` or `scene_id`, `end_image_url`, `duration_seconds` (5-20), `aspect_ratio` (auto follows the first frame), `resolution` (720p|1080p), `generate_audio` and `seed`.

## See also

* [`llms.txt` for this model](https://docs.roasos.com/models/video/flux-3-max/llms.txt) — the same facts as one plain-text file for an agent.
* `GET https://api.roasos.com/v1/catalog/flux-3-max` — the machine-readable form: enums, defaults, limits and prices. Refer to the [API reference](/api-reference/overview).
* [Jobs](/concepts/jobs) — how to poll a job and read its result.
* Provider endpoints: `blackforestlabs/flux-3-max/image-to-video` · `blackforestlabs/flux-3-max/text-to-video`.