# Flux 2 | Flex

Text-to-image generation with FLUX.2. Ultra-sharp realism, precise prompt interpretation, and seamless native editing for full creative control.

## API Information

- **Model Slug:** flux-2-flex
- **Branded URL:** https://www.eachlabs.ai/black-forest-labs/flux-2/flux-2-flex
- **Provider:** Black Forest Labs
- **Category:** Text to Image
- **Output Type:** image
- **Status:** active
- **Version:** 0.0.1
- **Estimated Processing Time:** 20 seconds
- **Last Updated:** 2026-04-29
- **Interactive Demo:** https://www.eachlabs.ai/ai-models/flux-2-flex

## Pricing

Pricing information not available.

## Input Schema

| Parameter | Type | Required | Default | Constraints | Description |
|-----------|------|----------|---------|-------------|-------------|
| prompt | string | Yes | - | - | The prompt to generate an image from. |
| image_size | string | No | landscape_4_3 | square_hd,square,portrait_4_3,portrait_16_9,landscape_4_3,landscape_16_9 | The size of the generated image. |
| guidance_scale | number | No | 3.5 | 1.5–10 | The guidance scale to use for the generation. |
| num_inference_steps | integer | No | 28 | 2–50 | The number of inference steps to perform. |
| safety_tolerance | string | No | 2 | 1, 2, 3, 4, 5 | The safety tolerance level for the generated image. 1 being the most strict and 5 being the most permissive. |
| enable_safety_checker | boolean | No | true | - | Whether to enable the safety checker. |
| output_format | string | No | jpeg | jpeg,png | The format of the generated image. |
| enable_prompt_expansion | boolean | No | true | - | Whether to expand the prompt using the model's own knowledge. |
| seed | integer | No | - | - | The seed to use for the generation. |

## Example Request

```bash
curl -X POST https://api.eachlabs.ai/v1/prediction/ \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "flux-2-flex",
  "input": {
    "prompt": "A high-quality 3D render of a cute baby eating ice cream."
  }
}'
```

## Output Schema

Response returned by `GET /v1/prediction/{id}` when the job completes:

```json
{
  "status": "success",
  "predictionID": "string",
  "output": "string (URL of generated image)",
  "metrics": {
    "predict_time": "number (seconds)"
  }
}
```

## Polling

```bash
curl https://api.eachlabs.ai/v1/prediction/{PREDICTION_ID} \
  -H "X-API-Key: YOUR_API_KEY"
```

| Status | Meaning |
|--------|---------|
| `processing` | Still running — poll again |
| `success` | Done — read `output` |
| `error` | Failed — read `message` / `details` |

## Webhook (alternative to polling)

Pass `"webhook_url": "https://your.host/path"` in the create request. Eachlabs POSTs this payload when the job ends:

```json
{
  "exec_id": "prediction-uuid",
  "status": "succeeded",
  "output": "https://...",
  "error": ""
}
```

`status` is `"succeeded"` or `"failed"`. `exec_id` equals the `predictionID` from create. Return 2xx within 30 seconds.

## Errors

Error body: `{ "status": "error", "message": "...", "details": "..." }`

| Code | Meaning |
|------|---------|
| `400` | Invalid input |
| `401` | Missing / invalid `X-API-Key` |
| `404` | Unknown model or prediction id |
| `429` | Rate limit — 100 creates / min, 10 concurrent per key |
| `5xx` | Retry with backoff |

## Overview

**flux-2-flex — Text-to-Image AI Model**

flux-2-flex, Black Forest Labs' specialized variant in the FLUX.2 family, delivers text-to-image generation optimized for superior typography and small detail preservation, solving the common challenge of inaccurate text rendering in AI-generated visuals. This text-to-image AI model excels in photorealistic outputs up to 4 megapixels with precise prompt adherence, making it ideal for users seeking "Black Forest Labs text-to-image" solutions with fine-grained control. Developed as part of the flux-2 lineup, flux-2-flex stands out for its up-to-3x faster processing while maintaining ultra-sharp realism and seamless editing capabilities.

## Usage Notes

- API Base URL: `https://api.eachlabs.ai/v1`
- Authentication: send `X-API-Key: YOUR_API_KEY`. Generate a key from the Eachlabs dashboard at https://www.eachlabs.ai/dashboard/api-keys.
- File-typed parameters (`*_url`, `image_url`, `video_url`, `audio_url`, etc.) accept publicly-reachable HTTPS URLs only. Upload your asset first (GCS / S3 / your CDN) and pass the resulting URL. Data-URIs and localhost URLs are rejected.
- For structured parameters (arrays / objects) send real JSON values, not stringified payloads.
- Monetary values are reported in USD; per-token / per-megapixel rates may be billed in micro-cents internally.
- Prefer `webhook_url` over polling for long-running predictions — see the Webhook Callback section.