---
title: "Run Flux Dev (flux-dev)"
method: POST
path: "/models/flux-dev"
tags: ["Run a model"]
---

# Run Flux Dev (flux-dev)

`POST /models/flux-dev`

## Request

- Base URL: `https://api.hedra.com/v3`
- URL: `https://api.hedra.com/v3/models/flux-dev`
- Auth: one of:
  - API key in header `Authorization`
  - HTTP bearer

Fast and light for quick concepts or high-volume social posts on a budget.

Submits an asynchronous job and returns `202` with a job id. Fetch the result at `GET /v3/jobs/{job_id}` — each item in its `outputs[]` follows the `OutputItem` schema — or track progress via `GET /v3/jobs/{job_id}/status` / the SSE stream at `GET /v3/jobs/{job_id}/stream`.

## Headers

- `Idempotency-Key` string

## Request body

- SubmitBodyFluxDev
  - `input` InputFluxDev, required: Model-specific inputs for `flux-dev`.
    - `prompt` string, required: Generation prompt.
    - `num_outputs` 1: Number of outputs generated per job. Only 1 is supported.
    - `enhance_prompt` boolean: Rewrite the prompt before generation. An LLM expands it into a fuller description and the model receives that text instead of the submitted one; the result's `prompt` reports what ran.
    - `aspect_ratio` '1:1' | '1:3' | '2:3' | '3:1' | '3:2' | '3:4' | '4:3' | '16:9' | '9:16' | '10:16' | '16:10', required: Output aspect ratio.
    - `resolution` '540p' | '720p' | '1080p' | '1440p (2K QHD)' | '2160p (4K UHD)', required: Output resolution.
    - `output_format` 'jpeg' | 'png': Output image format.
    - `seed` integer: Seed for reproducible output; omit for a random seed.
    - `guidance_scale` number: How closely the model follows the prompt. From 1 to 20.
    - `num_inference_steps` integer: Denoising steps to run. From 1 to 50.
  - `webhook` string, uri, nullable: URL to receive a signed completion webhook.

## Response `202`

Accepted. The job runs asynchronously; poll `status_url` / `result_url` from the ack.

- SubmitResponse
  - `job_id` string, required: This job's id — server-issued, and opaque.
  - `model` string, required: The resolved model id this job runs on.
  - `status` 'IN_QUEUE' | 'IN_PROGRESS' | 'COMPLETED' | 'FAILED', required: The four states a job can be in.
  - `status_url` string, required: Path of this job's status monitor: poll GET /v3/jobs/{job_id}/status for status, progress, and the estimated completion time.
  - `result_url` string, required: Path of the job resource itself: GET /v3/jobs/{job_id} returns the result envelope, including the outputs once it completes. Also the value of this response's `Location` header.
  - `estimated_completion_at` string, date-time, nullable: ISO-8601 instant this job is estimated to finish, as of this response. Null when no estimate is available yet, and when the job has already finished. The estimate can change while the job runs: poll `GET /v3/jobs/{job_id}/status` for the current one.

## Other responses

- `400`: Invalid or failed-validation request.
- `401`: Authentication failed: missing, malformed, or invalid credentials.
- `402`: The API wallet cannot cover this request. `error.billing` carries the balance, the price, and where to add funds.
- `403`: Insufficient scope or plan.
- `404`: Resource not found.
- `422`: Moderation refused the request's content.
- `429`: Rate limit exceeded.
- `500`: Internal error.

## Changes

- **2026-10-16** `06692d16e78a`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/hedra-labs/apis/hedra-api/changes/models/flux-dev/post.md)

---

[API](https://skmtc.dev/hedra-labs/apis/hedra-api.md) - [All operations](https://skmtc.dev/hedra-labs/apis/hedra-api/llms.txt) - [OpenAPI document](https://skmtc.dev/hedra-labs/apis/hedra-api/revisions/6ef35a11cefe?raw)