Black Forest Labs: FLUX.2 Klein 9B API

FLUX.2 [klein]-9B is the flagship high-speed model of the FLUX.2 family, featuring a 9-billion parameter Rectified Flow Transformer architecture. The name "klein" (German for "small") reflects its optimized efficiency, delivering sub-second inference (under 0.5s on modern hardware) without sacrificing photorealistic quality. It uniquely unifies text-to-image generation, single-image editing, and multi-reference generation (up to 5 images) within a single architecture. The 9B variant defines the Pareto frontier for visual quality versus latency, rivaling models five times its size in prompt adherence and anatomical accuracy. The price is calculated based on the unit price per cost point, where the cost value is returned in the response after the task is submitted. For example: `json { "id": "5aaeac12-5dbc-43ff-93f0-eb61cfe7274b", "polling_url": "https://api.us2.bfl.ai/v1/get_result?id=5aaeac12-5dbc-43ff-93f0-eb61cfe7274b", "cost": 1.7, "input_mp": 3.0, "output_mp": 1.0 } `

• Input: text, image
• Output: image
• File input: Supported
• Released: 2026-01-14
• Knowledge cutoff: 2025-09-30