FLUX.1 [pro] v1.1 Ultra by Black Forest Labs — 4MP high-res output with integrated upscaling and raw mode. $0.06/image, commercial.
Multiple FLUX Pro variants for different quality and resolution needs — all on the same Runflow API.
Commercial-grade — 6× faster, highest Elo, $0.04/MP
4MP high-res output with integrated upscaling and raw mode, $0.06/image
Open-weight, 12B params, $0.025/MP — non-commercial license
Speed-optimised — sub-second at $0.003/MP, Apache 2.0
Every model on Runflow is scored per vertical — not generic leaderboard numbers. Scores come from domain-expert evaluation on real production prompts.
| Use Case | Assessment | Notes |
|---|---|---|
| Portrait | Strong | Preserves fine skin texture and detail at high resolution |
| Fashion | Strong | Print-ready editorial output — no post-process upscaling needed |
| Product | Strong | Material properties and lighting preserved at 4MP |
| Creative | Strong | Raw mode produces more natural, less processed artistic outputs |
Full parameter reference for the flux-pro-v1-1-ultra model endpoint.
| Parameter | Type | Description |
|---|---|---|
| prompt | string | Text description of the image to generate. |
| aspect_ratio | string | Aspect ratio of the output. Options: square_hd, square, portrait_4_3, portrait_16_9, landscape_4_3, landscape_16_9. Default: "16:9". |
| num_images | integer | Number of images to generate per request. Range: 1–4. Default: 1. |
| raw | boolean | Generate less processed, more natural-looking images. Default: false. |
| output_format | string | Output format. Options: "jpeg", "png". Default: "jpeg". |
| safety_tolerance | string | Content moderation strictness. 1 = most strict, 6 = most permissive. Default: 2. |
| image_url | string | Reference image URL for style conditioning. Use with image_prompt_strength. |
| image_prompt_strength | float | Strength of the image conditioning. Range: 0–1. Default: 0.1. |
| enhance_prompt | boolean | Automatically enhance the prompt for better results. Default: false. |
| seed | integer | Random seed for reproducible outputs. |
| sync_mode | boolean | Return media as data URI without storing in request history. Default: false. |
Flux AI models are available on many platforms. Here's what makes the Runflow image generation API different.
Integrated upscaling pipeline produces 4-megapixel images that preserve fine detail, skin texture, and material properties — no post-process upscaler needed.
Toggle raw mode for less processed, more natural-looking outputs — useful for editorial, fine art, and photography workflows that prefer organic over polished.
Pass a reference image URL with adjustable strength (0–1) to guide style, composition, or colour palette without full img2img workflows.
4MP output is sufficient for A4 prints at 300 DPI — directly from the API without upscaling artefacts or quality loss.
Every output is scored by Runflow's Sentinel system at full resolution before delivery, catching quality issues automatically.
Same API, different strengths. Switch models with one parameter change.
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Get API access in minutes. No GPU setup, no infrastructure to manage. Pair with Sentinel to control the quality of every AI-generated image you ship.