---
title: "Flux 2 flux-2-flex-image-to-image API — Pricing, code samples | RunAPI"
url: "https://runapi.ai/models/flux-2/flex-image-to-image.md"
canonical: "https://runapi.ai/models/flux-2/flex-image-to-image.md"
locale: "en"
model: "Flux 2"
provider: "Black Forest Labs"
variant_id: "flux-2-flex-image-to-image"
sdk_model_id: "flux-2-flex-image-to-image"
modality: "image"
price_from_cents: 14
billing_unit: "call"
status: "active"
---

# Flux 2 flux-2-flex-image-to-image API

Same API, same SDK — switch variants by changing one parameter.

## Pricing

**$0.140** per call

Failed generations are not charged

## Spec sheet

| Field | Value |
|---|---|
| Model ID | `flux-2-flex-image-to-image` |
| Provider | Black Forest Labs |
| Modality | image |
| Task type | asynchronous |
| Billing unit | call |
| API endpoint | `/api/v1/flux_2/image_to_image` |
| Status | active |

## Install

```sh
npm install @runapi.ai/flux-2
```

## Quickstart

```sh
curl -X POST https://api.runapi.ai/api/v1/flux_2/image_to_image \
  -H "Authorization: Bearer $RUNAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "model": "flux-2-flex-image-to-image", "prompt": "..." }'
```

```js
import RunAPI from "@runapi.ai/flux-2";

const client = new RunAPI(process.env.RUNAPI_KEY);
const task = await client.create({
  model: "flux-2-flex-image-to-image",
  prompt: "...",
});
```

## FAQ

### Is the model ID stable across versions?

RunAPI keeps the model ID stable and handles compatible version refreshes without changing your request shape.

### What's the rate limit on this variant?

Per-key rate limits scale with usage tier. See pricing page for current limits.

### Can I switch variants later?

Yes — variant is a flag. Switch by changing the model parameter.

### Does it stream?

Where streaming is available, RunAPI streams end-to-end.

### Where do I report quality issues?

Open an issue on the public GitHub repo or email support.


## Related

Other Flux 2 variants:

- [flux-2-flex-text-to-image](https://runapi.ai/models/flux-2/flex-text-to-image.md) — `flex-text-to-image` · $0.140
- [flux-2-pro-image-to-image](https://runapi.ai/models/flux-2/pro-image-to-image.md) — `pro-image-to-image` · $0.050
- [flux-2-pro-text-to-image](https://runapi.ai/models/flux-2/pro-text-to-image.md) — `pro-text-to-image` · $0.050