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

# Use FLUX 3 Max with Comfy Router

> Call fal/flux-3-max through Comfy Router: endpoint, request shape and the response Router returns.

API Reference for `fal/flux-3-max`, served by Comfy Router from fal.

**Input:** Text, Image · **Output:** Video + Audio

## Quick start

Create a key in [your Comfy workspace](https://platform.comfy.org/profile/api-keys?onboarding=router) and export it as `COMFY_API_KEY`. The Python and TypeScript snippets use the Comfy SDKs (`pip install comfy-sdk` and `npm install @comfyorg/sdk`); the cURL snippet is the same call over raw HTTP.

**Model ID:** `fal/flux-3-max`

**Endpoint:** `POST https://api.comfy.org/v2/models/fal/flux-3-max`

**Wait for the result**

```python Python theme={null}
from comfy_sdk import Comfy

# Reads COMFY_API_KEY from the environment.
# The SDK automatically creates an idempotency key and reuses it for automatic retries.
with Comfy() as client:
    result = client.models.run(
        "fal/flux-3-max",
        {
            "duration": 5,
            "prompt": "A red panda walks along a mossy log in a sunlit forest. Ambient birdsong.",
            "resolution": "720p",
        },
    )

print(result)
```

```typescript TypeScript theme={null}
import { comfy } from "@comfyorg/sdk";

// Reads COMFY_API_KEY from the environment.
// The SDK automatically creates an idempotency key and reuses it for automatic retries.
const { data } = await comfy.models.run("fal/flux-3-max", {
  duration: 5,
  prompt: "A red panda walks along a mossy log in a sunlit forest. Ambient birdsong.",
  resolution: "720p",
});

console.log(data);
```

```bash cURL theme={null}
curl https://api.comfy.org/v2/models/fal/flux-3-max \
  -H "X-API-Key: $COMFY_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d "{\"duration\": 5, \"prompt\": \"A red panda walks along a mossy log in a sunlit forest. Ambient birdsong.\", \"resolution\": \"720p\"}"
```

**Queue and collect later**

The same body, sent to `POST https://api.comfy.org/v2/models/fal/flux-3-max/requests`. Router answers `201` with a `request_id` as soon as the run is admitted, and the result is collected once it is ready, from this process or another one. [Queued delivery](/development/comfy-router/queue) walks through status, cancellation and collection.

```python Python theme={null}
import asyncio
from comfy_sdk import AsyncComfy

# Reads COMFY_API_KEY from the environment.
# Each submit() call mints its own Idempotency-Key and reuses it for automatic retries.
async def main():
    async with AsyncComfy() as client:
        handle = await client.models.submit(
            "fal/flux-3-max",
            {
                "duration": 5,
                "prompt": "A red panda walks along a mossy log in a sunlit forest. Ambient birdsong.",
                "resolution": "720p",
            },
        )
        print("request_id:", handle.request_id)  # with the model ID, all another process needs

        # Poll until the request completes, waiting the Retry-After the server names.
        async for update in handle.iter_events():
            print(update.status, update.queue_position)

        # The provider's own payload, the same value models.run() returns.
        # A request that failed or was cancelled raises the typed Router error here.
        result = await handle.get()

    print(result)

asyncio.run(main())
```

```typescript TypeScript theme={null}
import { comfy } from "@comfyorg/sdk";

// Reads COMFY_API_KEY from the environment.
// Each submit() call mints its own Idempotency-Key and reuses it for automatic retries.
const handle = await comfy.models.submit("fal/flux-3-max", {
  duration: 5,
  prompt: "A red panda walks along a mossy log in a sunlit forest. Ambient birdsong.",
  resolution: "720p",
});
console.log("requestId:", handle.requestId); // with the model ID, all another process needs

// Poll until the request completes, waiting the Retry-After the server names.
for await (const update of handle.events()) {
  console.log(update.status, update.queuePosition);
}

// The same result models.run() returns. A request that failed or was cancelled rejects here.
const result = await handle.get();

console.log(result.data);
```

```bash cURL theme={null}
# 1. Submit. Router answers 201 with request_id, status_url, response_url and cancel_url.
curl https://api.comfy.org/v2/models/fal/flux-3-max/requests \
  -H "X-API-Key: $COMFY_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d "{\"duration\": 5, \"prompt\": \"A red panda walks along a mossy log in a sunlit forest. Ambient birdsong.\", \"resolution\": \"720p\"}"

# 2. Poll until status is COMPLETED, waiting the Retry-After seconds each response names.
REQUEST_ID="<request_id from the 201 body>"
curl -i https://api.comfy.org/v2/models/fal/flux-3-max/requests/$REQUEST_ID/status \
  -H "X-API-Key: $COMFY_API_KEY"

# 3. Collect. 200 with the model's native output, 202 with the status body while it is still running.
curl https://api.comfy.org/v2/models/fal/flux-3-max/requests/$REQUEST_ID \
  -H "X-API-Key: $COMFY_API_KEY"
```

## Schema

### Input

**aspect\_ratio** `string` (default: "auto")

Aspect ratio of the generated video. auto is 16:9 for a text prompt and follows the first image otherwise.

Possible values: `auto`, `21:9`, `2:1`, `16:9`, `4:3`, `1:1`, `3:4`, `9:16`

**duration** `integer` (default: 5)

Duration of the generated video in seconds, 5 to 20. fal bills per second of this value.

Range: `5` to `20`

**generate\_audio** `boolean` (default: true)

Generate synchronized audio. The price is the same.

**prompt** `string` *required*

Text prompt that describes the video and its sound.

**reasoning\_level** `string` (default: "high")

How much the model reasons about and expands the prompt before generation. high is slower. The price is the same.

Possible values: `low`, `high`

**resolution** `string` (default: "720p")

Resolution of the generated video. 1080p costs more per second than 720p.

Possible values: `720p`, `1080p`

**seed** `integer`

Random seed. A random seed is selected when omitted.

Generated from the schema Router serves at `GET /v2/models/fal/flux-3-max/openapi.json`, the same document it validates a call against before the request reaches the provider.

### Output

**seed** `integer`

The seed used for the generation.

**timings** `object`

Timing breakdown in seconds.

**video** `object` *required*

The generated video file.

**video.content\_type** `string`

MIME type of the video file.

**video.duration** `number`

Duration of the video in seconds.

**video.file\_name** `string`

Name of the video file.

**video.file\_size** `integer`

Size of the video file in bytes.

**video.fps** `number`

Frame rate of the video.

**video.height** `integer`

Height of the video in pixels.

**video.num\_frames** `integer`

Number of frames in the video.

**video.url** `string` *required*

URL of the generated video.

**video.width** `integer`

Width of the video in pixels.

## Examples

### Input

```json theme={null}
{
  "duration": 5,
  "prompt": "A red panda walks along a mossy log in a sunlit forest. Ambient birdsong.",
  "resolution": "720p"
}
```

### Output

```json theme={null}
{
  "seed": 42,
  "video": {
    "content_type": "video/mp4",
    "duration": 5.041666666666667,
    "file_name": "video.mp4",
    "file_size": 4404019,
    "fps": 24,
    "height": 704,
    "num_frames": 121,
    "url": "https://example.invalid/fal/flux-3-max/video.mp4",
    "width": 1280
  }
}
```

## Before you ship

The SDKs create an `Idempotency-Key` and reuse it for automatic retries. For manual retries, reuse the original key. Router can hold the connection for up to 10 minutes.

When a request fails, Router sends an `X-Comfy-Error-Type` response header explaining why. A `422` means Router rejected the input before calling the provider, and a `413` means the request body was larger than Router accepts. Download generated assets promptly because [result URLs can expire](/development/comfy-router/reference#result-assets).

Any size limit named in a field description above is the provider's own bound on that field, quoted from the provider's specification. Router applies a separate cap to the whole request body, which base64-encoded media counts against: see [request body size](/development/comfy-router/limitations#request-bodies-are-capped).

This page documents one partner model called through Comfy Router. The same `comfy-sdk` / `@comfyorg/sdk` package also ships a second client, for running a whole ComfyUI workflow graph on Comfy Cloud: `Comfy(api_key=...)` / `new Comfy({ apiKey })`, with `client.workflows`, `client.assets` and `client.jobs`. See [Comfy SDKs](/development/api-development/sdks).

> **[Headers](/development/comfy-router/headers)**
>
> Authentication, idempotency, request IDs, error buckets, retry pacing, spend limits.

> **[Using the Router API](/development/comfy-router/api)**
>
> Model discovery, validation errors, retries, and billing.

> **[Limitations](/development/comfy-router/limitations)**
>
> What Router does not do today, and what to use instead.


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