FLUX 3 API

Endpoints

4

Text to video, image to video, video extend and video upscale.

Clip length

5-20 s

Whole seconds, with sound generated in the same pass.

Cheap preview tier

Draft

A fast, low-cost pass at 720p for checking a shot before a full render.

Largest upscale

3x

Enlarge a finished clip from 1.5 to 3 times, keeping its sound.

Renders: on screen as written. Softened: generated, but milder than what was written. Refused: rejected. Not tested yet: we have not run that level on that mode.

• Text to video

  A line of dialogue over rain and rails

  

  Night inside a 1950s sleeper train compartment with polished walnut panels. A woman in her early thirties in a black silk slip dress sits on the edge of the bunk, one strap slipping off her shoulder. A man in his late thirties in an unbuttoned white dress shirt leans in the doorway. She looks up at him and says softly, "You're late." He smiles, steps into the compartment and sits down beside her on the bunk. Warm amber reading-lamp light, town lights streaking past the rain-flecked window, slow push-in, shallow depth of field, 35mm film look. Sound: the steady clatter of the rails, rain on the glass, her quiet voice.

  Why it works. A short scene with one spoken line in quotes, a Sound: line for the room, and a named camera move. The line in the clip matched the prompt word for word, and the camera pushed in slowly.

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• Text to video

  Two people, one line, practical light

  

  An empty boxing gym after hours, rain drumming on the skylight. Two men in their forties face each other at the edge of the ring. One, in an unbuttoned grey work shirt, slowly wraps the other's hands with white tape; the other, in a damp black tank top, watches his face instead of his hands. A single hanging bulb sways overhead and throws moving shadows across them. He tightens the last wrap, holds on a moment longer and says in a low voice, "Don't hold back tonight." Slow handheld camera, warm tungsten light against cold blue window light, film grain. Sound: rain, the creak of the ring ropes, tape tearing, low voices.

  Why it works. Warm bulbs against cold window light set the look, and the sounds that matter (rain, rope creak, tape) are listed. The spoken line came through as written; the shirt came out open at the collar rather than fully open.

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• Text to video

  Preview a vertical shot at the draft tier

  

  A rainy night in a chrome-and-neon roadside diner. Two women in their thirties share a red vinyl booth by the window: one in a satin camisole with a leather jacket slipping off her shoulders, the other in an oversized men's white shirt with the sleeves rolled up. One reaches across and tucks a strand of wet hair behind the other's ear; they both start laughing. Pink and teal neon reflects on the wet window, rain streaks down the glass, slow drifting handheld camera, vertical framing. Sound: rain, a jukebox playing a slow song, soft laughter.

  Why it works. The same kind of prompt at the cheaper draft tier. Detail is softer than standard, but framing, wardrobe and the neon on the glass are easy to judge before a full render.

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• Image to video

  One action from a still

  

  She slides her sunglasses down over her eyes, turns her head toward the camera and breaks into a slow, easy laugh while the sea breeze lifts her damp hair and the loose linen shirt. The camera drifts in a slow arc around her as the golden light flares across the lens. Sound: waves breaking on the rocks below, distant gulls, a soft wind.

  Why it works. The photo supplies the person and the place, so the prompt only needs the action, the camera arc and the sound. Her face drifted slightly narrower after the sunglasses went on, and the first second or two has her hands covering it.

  This mode starts from your own image: add it in the playground before you run.

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• Image to video

  Go from one frame to another

  

  He sets the coffee mug down on the windowsill, walks across the loft and sits on the paint-splattered stool, turning to face the camera as the first sunrise floods through the tall windows and turns the cool blue room warm gold. One continuous shot, the camera slowly pushing in. Sound: footsteps on old floorboards, birds outside, the city waking up.

  Why it works. With a first and a last image the clip travels between them. The light change was too big to blend, so the model cut hard partway through even though the prompt asked for one shot; keep the two frames closer if you need a smooth change.

  This mode starts from your own image: add it in the playground before you run.

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• Video extension

  Continue the same shot with the next gesture

  

  The same close-up continues in one unbroken take, the camera stays on her face and shoulders the whole time. She slowly draws her fingertip from her lower lip down her throat to her collarbone, eyes locked on the lens, a slow knowing smile. Behind her a towering wall of sand rolls in across the dunes and swallows the setting sun, the light shifting from gold to deep amber, wind whipping her hair across her face. 35mm film grain, shallow depth of field, rising wind and sand hiss.

  Why it works. Describe what happens next, not the clip again, and keep the camera on the same framing. When we asked for a pull-back or a new angle, the segment cut to a different shot; staying in the close-up gave one continuous take.

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A 5-second clip starts at $0.3 at 1080p and $0.3 at 720p.

The playground shows the exact price for your settings before you run. Failed or timed-out tasks are usually not charged. Some models charge for content refusals as stated on their model page; check those billing terms before submitting.

About FLUX 3

FLUX 3 puts picture and sound in one pass, lets you test a shot in draft before paying for a full render, and carries a finished clip on through extend and upscale. Black Forest Labs' review keeps generation to the Mild level, so it suits trailers, dialogue scenes, product and mood pieces.