# Flux Dev

> Flux Dev: fast pictures from a description — photorealism and illustrations in seconds.

Flux Dev is a Black Forest Labs model for pictures from a text description. Good at photorealism, portraits and illustrations; a picture is ready in a few seconds.


### Prompt only — the model creates the picture from scratch.

ID: `flux-dev` · $0.033 per image · under 1 min

**Parameters** (field `input`)

| Parameter | Required | Description | Values (default in bold) |
|---|---|---|---|
| `prompt` | yes | What to draw or what to change | text, up to 2000 chars |
| `aspect_ratio` | no | Image shape | **`1:1`** `16:9` `9:16` `4:3` `3:4` `3:2` `2:3` `21:9` `9:21` `4:5` `5:4` |
| `output_format` | no | File format | **`webp`** `jpg` `png` |

**Example**

```bash
curl -X POST https://mixmedia.tech/api/v1/jobs/createTask \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"flux-dev","input":{"prompt":"A cat astronaut in a neon city, cinematic light","aspect_ratio":"1:1"}}'
```

```python
import os, requests

r = requests.post(
    "https://mixmedia.tech/api/v1/jobs/createTask",
    headers={"Authorization": f"Bearer {os.environ['API_KEY']}"},
    json={
      "model": "flux-dev",
      "input": {
        "prompt": "A cat astronaut in a neon city, cinematic light",
        "aspect_ratio": "1:1"
      }
    },
)
print(r.json())  # {"code": 200, "data": {"taskId": "..."}}
```

```javascript
const r = await fetch("https://mixmedia.tech/api/v1/jobs/createTask", {
  method: "POST",
  headers: { Authorization: `Bearer ${process.env.API_KEY}`, "Content-Type": "application/json" },
  body: JSON.stringify({
    "model": "flux-dev",
    "input": {
      "prompt": "A cat astronaut in a neon city, cinematic light",
      "aspect_ratio": "1:1"
    }
  }),
});
console.log(await r.json()); // { code: 200, data: { taskId: "..." } }
```

## Compatibility

Requests in the OpenAI format and other popular API formats work too:

- `model`: `flux-dev`, `black-forest-labs/flux-dev`, `black-forest-labs/flux:dev`, `flux.1-dev`, `flux-1-dev`, `flux`.
- `size` instead of `aspect_ratio`: a ratio (`16:9`) or exact pixels (`1600x1200`) — we use the closest supported ratio.
- Photos can go in `image_urls`, `image_input` or `input_urls`. Parameters may also be sent at the top level of the body, without the `input` wrapper.
- `resolution` in any case (`1k`, `2K`); `jpg` and `jpeg` are the same. `n` must be `1` (one image per request).
- `nsfw_check`, `official_fallback`, `google_search` are accepted but do not change the result.

## Result



Same as any task: call [recordInfo](https://docs.mixmedia.tech/en/endpoints/record-info) or receive a [callback](https://docs.mixmedia.tech/en/callbacks). Image links are in `resultJson` (kept for 3 hours — download right away).

Upload your photos via [files/upload](https://docs.mixmedia.tech/en/endpoints/upload) or pass any public https links.

## Error handling

API responses are JSON `{"code", "msg", "data"}`; errors also have a string `error` field (type). **On `/api/v1/*` the HTTP status matches body `code`.**

### Example response bodies

**400**

```json
{
  "code": 400,
  "msg": "input.duration: must be between 4 and 30, or \"auto\" / -1",
  "data": null,
  "error": "invalid_request_error"
}
```

**401**

```json
{
  "code": 401,
  "msg": "Authentication failed. Please check your API key",
  "data": null,
  "error": "authentication_error"
}
```

**402**

```json
{
  "code": 402,
  "msg": "Insufficient balance. Please top up and try again. Available: $0.01, required: $0.015. Top up at https://mixmedia.tech/cabinet/billing",
  "data": {
    "balance": "0.0100",
    "required": "0.0150",
    "currency": "USD",
    "topUpUrl": "https://mixmedia.tech/cabinet/billing"
  },
  "error": "payment_required"
}
```

**429**

```json
{
  "code": 429,
  "msg": "Rate limit exceeded: 10 createTask/upload requests per 10 s per key. Retry after 8s",
  "data": null,
  "error": "rate_limit_error"
}
```

**500**

```json
{
  "code": 500,
  "msg": "Internal server error",
  "data": null,
  "error": "server_error"
}
```

### Codes on createTask / upload

| code | error | Meaning | What to do |
|---|---|---|---|
| 400 | `invalid_request_error` | Invalid parameter or body | See `msg` |
| 400 | `unsupported_model` | Unknown model | [Model list](https://docs.mixmedia.tech/en/models) |
| 401 | `authentication_error` | Missing or invalid key | Check the key |
| 402 | `payment_required` | Not enough balance | Top up |
| 403 | `permission_error` | No access | Contact support |
| 429 | `rate_limit_error` | Too many requests | Wait for `Retry-After` |
| 505 | `model_disabled` | Model temporarily disabled | Pick another |
| 500 | `server_error` | Our failure | Retry later |

Example `msg` values: `Authentication failed. Please check your API key` (401); `Insufficient balance. Please top up and try again…` (402).

### Task errors (recordInfo)

If the task was created and then failed: `state: "fail"` (alias `status: "failed"`), `failCode` / `failMsg`, and `error: { code, message, type }`. Money is refunded (`refunded: true`).

| failCode | error.type | Meaning |
|---|---|---|
| 400 | `nsfw_content_detected` / `invalid_request_error` | Moderation — `failMsg` is upstream text verbatim |
| 422 | `invalid_request_error` | The model rejected the parameters (e.g. a photo could not be downloaded) |
| 501 | `server_error` | The model could not generate (`failMsg`) |
| 504 | `timeout_error` | Timed out — retry |
| 500 / 503 | `server_error` | Service temporarily unavailable |

### Rate limits

| What | Limit |
|---|---|
| createTask and upload | 20 per 10 s per key |
| recordInfo / list / balance | 100 per 10 s per key |

Over the limit — HTTP 429 and `Retry-After`.