FLUX 3 Max

Endpoint

POST https://api.roasos.com/v1/video/flux-3-max

Send your API key as a bearer token. The key needs the scope api:write. Every paid request also needs an Idempotency-Key header.

The envelope fields quote_only, quote_id, webhook_url and wait_timeout_seconds behave the same on each model endpoint. Refer to Jobs and Quotes and credits.

Good at

Use FLUX 3 Max for long single takes: product hero moves, b-roll and scene clips. end_image_url sets the last frame after a first frame, so the shot lands on an exact end card. Sound is on by default. Set generate_audio to false when you add your own track. The price does not change. FLUX 3 Max has no reference input. For a person or a product from reference images, use Kling 4.0 or Seedance 2.5.

Pricing

The unit is one clip. Pricing key: flux-3-max.

The credits come from the roasOS pricing table. No other field changes the price. To get the exact price of your request, send it with quote_only: true first.

Modes

• text-to-video
• image-to-video

roasOS selects the mode from the media fields of your request. You do not send a mode.

Provider endpoints: blackforestlabs/flux-3-max/image-to-video · blackforestlabs/flux-3-max/text-to-video.

Request fields

The schema is strict. A field that is not in this table gets 400 unsupported_option. The field names are the roasOS role names. One role has one name in every family.

Media

This endpoint accepts these media roles:

• image_url — first frame (or the single source image)
• end_image_url — last frame
• scene_id — first frame — a scene this workspace owns

Every other role is refused: avatar_id, elements, product_id, product_images, references, reference_images, scene_image, video_urls, video_url, audio_urls, audio_url, voice_id. A refused role gets 400 unsupported_option.

Prompt

Limit 10,000 characters. The model expands the prompt before it makes the video.

• Write one clear prompt: subject, action, setting, camera and light.
• Describe a long take as one continuous action with one camera move.
• In image-to-video, describe the motion only.
• Direct the sound, or the model makes its own.

Not exposed

These catalog entries describe omitted inputs, pinned values and source constraints. They do not imply that the provider accepts every listed field.

• reasoning_level — pinned to "high", the provider default (the model expands the prompt).
• keyframes — not accepted by this public endpoint.
• references — not accepted by this public endpoint.
• avatar_id — not accepted by this public endpoint.
• product_id — not accepted by this public endpoint.
• video_urls — not accepted by this public endpoint.
• audio_urls — not accepted by this public endpoint.
• audio_url — not accepted by this public endpoint.
• negative_prompt — not accepted by this public endpoint.
• cfg_scale — not accepted by this public endpoint.
• shot_type — not accepted by this public endpoint.
• multi_prompt — not accepted by this public endpoint.

Result

The result kind is video. Always present: url.

{
  "data": {
    "id": "gen_…",
    "kind": "video",
    "model": "flux-3-max",
    "status": "completed",
    "result": {
      "url": "https://cdn.roasos.com/workspaces/ws_01/result"
    }
  }
}

The files are immutable objects on https://cdn.roasos.com. A result URL is a valid media input for your next request.

Example

The three steps are always the same: quote, run, poll.

# 1. Quote. Nothing is spent.
curl -X POST https://api.roasos.com/v1/video/flux-3-max \
  -H "Authorization: Bearer roasos_sk_live_..." \
  -H "Idempotency-Key: 0f1c9e2a-flux-3-max-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_only":true,"prompt":"A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."}'
# 200 { "data": { "kind": "quote", "quote_id": "q_7Hk...", "credits": 11, "expires_at": "...",
#        "confirmation": { "model": "flux-3-max", "example": "5s_720p" } } }

# 2. Run. Same body, same Idempotency-Key, quote_id in place of quote_only.
curl -X POST https://api.roasos.com/v1/video/flux-3-max \
  -H "Authorization: Bearer roasos_sk_live_..." \
  -H "Idempotency-Key: 0f1c9e2a-flux-3-max-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_id":"q_7Hk...","prompt":"A woman holds the bottle at eye level in a bright kitchen, morning light, static camera."}'
# 201 { "data": { "id": "gen_...", "status": "queued", "credits_reserved": 11 } }

# 3. Poll, then read the result.
curl https://api.roasos.com/v1/jobs/gen_.../status -H "Authorization: Bearer roasos_sk_live_..."
curl https://api.roasos.com/v1/jobs/gen_.../result -H "Authorization: Bearer roasos_sk_live_..."

The deprecated path

POST /v1/generations still reaches this model for one minor version. It is deprecated. This is how it maps:

POST /v1/video/flux-3-max with prompt, image_url or scene_id, end_image_url, duration_seconds (5-20), aspect_ratio (auto follows the first frame), resolution (720p|1080p), generate_audio and seed.

See also

• llms.txt for this model — the same facts as one plain-text file for an agent.
• GET https://api.roasos.com/v1/catalog/flux-3-max — the machine-readable form: enums, defaults, limits and prices. Refer to the API reference.
• Jobs — how to poll a job and read its result.
• Provider endpoints: blackforestlabs/flux-3-max/image-to-video · blackforestlabs/flux-3-max/text-to-video.