FLUX.2 [klein] 4B

by Black Forest Labs January 15, 2026

FLUX.2 [klein] 4B is a 4-step distilled image generation and editing model optimized for ultra-low latency inference. It delivers near real-time performance with strong visual quality, enabling interactive workflows and responsive production systems on more constrained hardware.

Text to Image

Bioluminescent Tidal Observatory Interior

Request

{
  "taskType": "imageInference",
  "taskUUID": "a19afcd7-2318-4d36-90bd-db71cf2e2a5b",
  "model": "runware:400@4",
  "positivePrompt": "A luminous coastal research observatory built inside a giant glass tide chamber at night, panoramic interior view, moonlit ocean visible beyond curved transparent walls, bioluminescent algae flowing through sculptural water channels, brass instruments, suspended holographic star maps, polished basalt floors reflecting cyan and amber light, a solitary astronomer in a sleek weatherproof cloak studying glowing marine samples, cinematic wide composition, intricate environmental storytelling, ultra-clean details, elegant futuristic architecture, misty sea air, dreamy yet precise, premium concept art, high visual coherence",
  "negativePrompt": "blurry, low detail, noisy, distorted anatomy, extra limbs, duplicate person, cropped, text, watermark, logo, overexposed, flat lighting, cluttered composition",
  "width": 1344,
  "height": 768,
  "seed": 79004,
  "steps": 4,
  "CFGScale": 3.5
}

Response

{
  "taskType": "imageInference",
  "taskUUID": "a19afcd7-2318-4d36-90bd-db71cf2e2a5b",
  "imageUUID": "4c1c6fb9-57ae-4152-ba09-b3756de37b40",
  "imageURL": "https://im.runware.ai/image/os/a05d22/ws/2/ii/4c1c6fb9-57ae-4152-ba09-b3756de37b40.jpg",
  "seed": 79004,
  "cost": 0.0006
}

Text to Image

Bioluminescent Tidepool Observatory Interior

Request

{
  "taskType": "imageInference",
  "taskUUID": "db4102b6-378a-465e-bdd8-528274811047",
  "model": "runware:400@4",
  "positivePrompt": "A retro-futurist coastal observatory built into black volcanic cliffs above a bioluminescent tidepool lagoon at blue hour, vast curved glass walls, brass instruments, polished wood consoles, suspended orrery shaped like seashell spirals, glowing cyan and violet reflections rippling across the interior, a solitary naturalist in a deep teal coat sketching luminous jellyfish drifting below the glass floor, art nouveau marine motifs, cinematic composition, intricate environmental storytelling, ultra-clean forms, soft mist outside, distant lighthouse beam, highly detailed, elegant color harmony, surreal yet believable, premium concept art look",
  "negativePrompt": "blurry, low resolution, noisy, distorted anatomy, extra limbs, duplicate person, oversaturated, flat lighting, cluttered composition, text, watermark, logo, frame, cropped subject, deformed architecture",
  "width": 1536,
  "height": 1024,
  "seed": 51482,
  "steps": 4,
  "CFGScale": 3.5
}

Response

{
  "taskType": "imageInference",
  "taskUUID": "db4102b6-378a-465e-bdd8-528274811047",
  "imageUUID": "3ba1aac1-57cf-4a7c-91a8-3915cd313e1c",
  "imageURL": "https://im.runware.ai/image/os/a18d05/ws/2/ii/3ba1aac1-57cf-4a7c-91a8-3915cd313e1c.jpg",
  "seed": 51482,
  "cost": 0.0006
}

Text to Image

Bioluminescent Desert Observatory Nightscape

Request

{
  "taskType": "imageInference",
  "taskUUID": "0992ee97-839f-44e8-a170-70527a090cf4",
  "model": "runware:400@4",
  "positivePrompt": "A cinematic wide shot of a remote astronomical observatory rising from a bioluminescent desert at midnight, vast dunes dusted with glowing blue mineral veins, sleek modular domes and antenna arrays reflecting starlight, a glass walkway suspended over shallow luminous salt flats, two tiny researchers in elegant cold-weather field suits for scale, sky filled with dense stars, a bright nebula band, and faint aurora ribbons near the horizon, crisp dry air, subtle wind-blown sand trails, luminous cactus-like alien flora scattered in the foreground, color palette of deep indigo, teal, silver, and electric cyan, ultra-detailed, atmospheric perspective, sharp focal clarity, premium concept art, realistic materials, dramatic yet serene mood",
  "negativePrompt": "blurry, low detail, noisy, oversaturated, distorted architecture, extra limbs, duplicate people, text, watermark, logo, frame, cropped, out of focus, muddy colors, cartoon, lowres",
  "width": 1536,
  "height": 864,
  "seed": 32039,
  "steps": 4,
  "CFGScale": 3.5
}

Response

{
  "taskType": "imageInference",
  "taskUUID": "0992ee97-839f-44e8-a170-70527a090cf4",
  "imageUUID": "ac6a8b3a-2a6d-400b-8b78-a2d91654b4ea",
  "imageURL": "https://im.runware.ai/image/os/a20d05/ws/2/ii/ac6a8b3a-2a6d-400b-8b78-a2d91654b4ea.jpg",
  "seed": 32039,
  "cost": 0.0006
}

Text to Image

Bioluminescent Desert Bazaar Twilight

Request

{
  "taskType": "imageInference",
  "taskUUID": "a04b1e78-e91c-4f50-b5aa-5aaf45787d54",
  "model": "runware:400@4",
  "positivePrompt": "A cinematic twilight bazaar in a vast desert of pale violet dunes, glowing bioluminescent lanterns hanging from silk canopies, mirrored pools reflecting a giant crescent moon, merchants in ornate nomadic attire, glass vessels filled with luminous spices, gentle wind lifting embroidered fabrics, a towering fossilized skeleton arch in the background, teal and amber color palette, atmospheric haze, crisp foreground detail, immersive depth, elegant composition, highly detailed, surreal realism",
  "negativePrompt": "blurry, low detail, flat lighting, oversaturated, distorted anatomy, duplicated people, extra limbs, warped architecture, text, watermark, logo, frame, cropped subject, noisy shadows",
  "width": 1024,
  "height": 576,
  "seed": 53982,
  "steps": 4,
  "CFGScale": 3.5
}

Response

{
  "taskType": "imageInference",
  "taskUUID": "a04b1e78-e91c-4f50-b5aa-5aaf45787d54",
  "imageUUID": "602ff884-6f08-457d-b616-5d1143491e92",
  "imageURL": "https://im.runware.ai/image/os/a20d05/ws/2/ii/602ff884-6f08-457d-b616-5d1143491e92.jpg",
  "seed": 53982,
  "cost": 0.0006
}