What Flux 3 is best at
Keyframe pinning
Give Flux 3 up to 10 images and tell it which frame each one lands on in a 24 fps timeline. The model animates between them, so a storyboard becomes a shot with the beats exactly where you drew them.
Draft, then enhance
Flux 3 Draft renders at 720p for roughly 3.5x less than the full model and hands back a draft cache. Pass that cache back and the same shot — same motion, same timing — is rendered again at full 1080p.
Extend existing video
Feed in a clip up to 15 seconds and 50 MB and describe what happens next. Flux 3 continues the footage, which is how you get past the 20-second single-pass ceiling.
Audio at no extra cost
Sound is generated alongside the picture in every mode — text, image, first-last-frame, keyframes, and extend — and switching it on changes nothing about the price.
Flux 3 at a glance
Prompt ideas for Flux 3
Built to Flux 3’s strengths — steal these to get started.
How to use Flux 3 on Genfire
- 1
Describe it
Write a prompt — or upload an image or reference media, and pick Flux 3 in the model selector.
- 2
Generate & compare
Render the video, iterate on the prompt, or run the same brief on a sibling model to compare — all from one credit balance.
- 3
Finish & publish
Send the result into Genfire's editor, upscaler, and audio tools, then export platform-ready output.
What Flux 3 actually does
Flux 3 is a video model built around control points rather than a single prompt. The plain modes are all there — text-to-video, image-to-video from a start frame, and first-last-frame where you give it both ends of the shot — but the mode that sets it apart is keyframes. You supply up to 10 images and a frame index for each, counted in a 24 fps timeline, and Flux 3 renders the motion between them so that each image appears at exactly the moment you asked for. First-last-frame is really the two-keyframe special case. For anyone working from a storyboard, this replaces guessing at how a prompt will pace itself with pinning the beats and letting the model fill the gaps.
The second idea is the Draft tier. Flux 3 Draft renders the same shot at a fixed 720p for about 3.5x less than the full model, and every draft comes back with a draft cache alongside the video. Pass that cache back — on Genfire, the studio offers it as an action on the finished draft, and the API takes it as draft_cache_url — and the shot is rendered again at full 1080p with the same motion and timing. The cache already encodes the prompt, duration, and aspect ratio, so there is nothing to re-enter. The workflow that falls out of this is cheap iteration: run five drafts, keep one, promote it. Draft is available across all four routing modes, so keyframed and extended shots can be previewed the same way.
The third is extend. Flux 3 tops out at 20 seconds in a single pass, but the extend mode takes an existing MP4 of up to 15 seconds and 50 MB and continues it from a description of what happens next, with audio carried through. Chaining extends is how a Flux 3 shot grows past its ceiling; combined with the Genfire video editor you can also cut those continuations against clips from Wan 3.0, Seedance 2.5, or Kling. Output is 720p or 1080p at eight aspect ratios from 21:9 down to 9:16, plus auto, and synchronized audio is on in every mode at no additional cost. Flux 3 and Flux 3 Draft are live in the browser studio, on the API as video.flux_3 and video.flux_3_draft, on the MCP server, and in the CLI.
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Flux 3 — frequently asked questions
What is Flux 3?
Flux 3 is a video generation model from Black Forest Labs, the team behind the Flux image models. It renders 5 to 20 seconds of video at 720p or 1080p with synchronized audio included, and supports text-to-video, image-to-video, first-last-frame, keyframe pinning, and extending an existing clip.
How long can a Flux 3 video be?
A single Flux 3 generation runs from 5 to 20 seconds, chosen in whole seconds. To go longer, use the extend mode, which takes a clip of up to 15 seconds and 50 MB and continues it, and chain extensions or cut them together in the Genfire video editor.
Does Flux 3 generate audio?
Yes. Flux 3 generates synchronized audio alongside the video in every mode, including keyframes and extend, and the audio is included at no extra cost. Generating with sound costs the same as generating without it.
What are Flux 3 keyframes?
Keyframes let you pin up to 10 images to specific frame positions in a 24 fps timeline. Flux 3 animates between them so each image appears at exactly the frame you set. A first-last-frame request is the same idea with two keyframes at the start and end of the clip.
What is Flux 3 Draft?
Flux 3 Draft is a cheaper preview tier that renders the same shot at a fixed 720p for roughly 3.5x less than full Flux 3. Every draft returns a draft cache; pass it back and the identical shot is rendered at full 1080p, with the same motion and timing, without re-entering the prompt.
How do I promote a Flux 3 draft to 1080p?
In the Genfire studio, a finished draft offers an enhance action that submits its cache for a full-quality render. On the API, pass the draft_cache_url the draft returned to the same model and the request routes to the enhance endpoint automatically. The cache carries the prompt, duration, and aspect ratio, so nothing else is needed.
How do I use Flux 3 on Genfire?
Pick Flux 3 or Flux 3 Draft in the browser video studio, then attach a start image, a first and last frame, up to 10 keyframes, or a source clip to extend — the mode is detected from what you attach. The same model is available through the Genfire API, the MCP server, and the CLI with the same limits.
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