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This page covers FLUX.1 [pro] text-to-image models that are still callable on APIYI. The latest FLUX.2 generation and the editing-focused FLUX.1 Kontext are documented in the FLUX Overview.

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Version Snapshot

Model IDReleased (UTC+0)APIYI PriceStatusBest For
flux-pro-1.1-ultra2024-11$0.0500🟡 MaintainedLegacy ultra-resolution (4MP)
flux-pro-1.12024-10$0.0350🟡 MaintainedLegacy text-to-image baseline
flux-pro2024-08$0.0400🟡 MaintainedFirst-gen pro, legacy compat
flux-dev2024-08$0.0200🟡 MaintainedDev/test, open-weights local inference
For new projects, prefer FLUX.2: flux-2-pro matches flux-pro-1.1’s tier with major upgrades in quality, multi-reference, long prompts, and 4MP output — at similar or lower cost. See migration guidance below.

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Per-Version Specs

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flux-pro-1.1-ultra

  • Released: 2024-11 (UTC+0)
  • APIYI Price: $0.0500 (official $0.06, saves 17%)
  • Max output: ~4MP (highest in FLUX.1 series)
  • Key features: Ultra-resolution, optional raw mode (closer to candid photography)
  • Known limits: Single reference only, no hex color control, no grounding search
  • Official docs: docs.bfl.ai/flux_models/flux_1_1_pro_ultra_raw

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flux-pro-1.1

  • Released: 2024-10 (UTC+0)
  • APIYI Price: $0.0350 (official $0.04, saves 12.5%)
  • Max output: ~1.6MP (e.g., 1024×1536)
  • Key features: Improved quality and prompt adherence over 1.0, industry baseline
  • Known limits: Single reference, short prompts (no 32K)
  • Official docs: docs.bfl.ai/flux_models/flux_1_1_pro

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flux-pro

  • Released: 2024-08 (UTC+0)
  • APIYI Price: $0.0400 (official $0.04, same)
  • Max output: ~1.6MP
  • Key features: BFL’s first commercial pro, baseline text-to-image
  • Known limits: Quality and adherence below 1.1 — no reason for new projects

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flux-dev

  • APIYI Price: $0.0200
  • Max output: ~1MP
  • Key features: Open-weights variant (FLUX.1 [dev], non-commercial license), self-host on your own GPU
  • Known limits: Quality below the [pro] tier, mainly for research, prototyping, local inference validation
  • Official weights: huggingface.co/black-forest-labs/FLUX.1-dev

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Migration Guidance

1

Assess differences

FLUX.2 fully supersedes FLUX.1 [pro]: 4MP output (vs 1.6MP), up to 8 multi-references (vs 1), 32K-token prompts (vs short), native hex color control, typography specialist tier. Pricing within 1MP is similar or lower.
2

Run side-by-side

Generate the same prompt set on flux-pro-1.1 and flux-2-pro for a week. Compare text legibility, multi-object consistency, brand color fidelity. FLUX.2 [pro] wins across the board in most cases.
3

Roll out gradually

Cut 10% of traffic to flux-2-pro first, observe quality and cost for a week, then ramp to 100%. Costs are roughly equivalent at 1MP and noticeably cheaper at 4MP.
4

Handle parameter differences

Most parameters carry over, but note:
  • FLUX.1 [pro] takes a single reference image; FLUX.2 uses the image[] array (OpenAI-compatible)
  • FLUX.1 doesn’t support prompt_upsampling; FLUX.2 [pro/max/flex] does
  • Some legacy aspect-ratio identifiers (e.g., aspect_ratio) are replaced by width/height or the size string in FLUX.2

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Legacy Call Example

{/* Call any historical version by changing only the model field — all other params are OpenAI Images API compatible */}
from openai import OpenAI
import requests

client = OpenAI(api_key="sk-your-api-key", base_url="https://api.apiyi.com/v1")

resp = client.images.generate(
    model="flux-pro-1.1-ultra",
    prompt="A serene mountain landscape at golden hour, raw photo style",
    size="2048x1536"
)

# data[0].url is valid for only 10 minutes
url = resp.data[0].url
with open("legacy.jpg", "wb") as f:
    f.write(requests.get(url, timeout=30).content)

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Cost Comparison

By typical volume (flat per-image price):
VersionAPIYI Price100 images1,000 images10,000 images
flux-pro-1.1-ultra$0.05$5.00$50.00$500.00
flux-pro-1.1$0.035$3.50$35.00$350.00
flux-pro$0.04$4.00$40.00$400.00
flux-dev$0.02$2.00$20.00$200.00
flux-2-pro (new)$0.03$3.00$30.00$300.00
flux-2-max (new)$0.07$7.00$70.00$700.00
How to choose: For new projects, prefer FLUX.2 (flux-2-pro for general use, flux-2-max for flagship). Keep FLUX.1 [pro] running only when legacy integrations are deeply wired and regression testing is impractical. flux-dev remains a viable low-cost dev/test option.