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Head to head · Image generation · October 2026 research run

Black Forest Labs FLUX API vs Iris-3B

Black Forest Labs FLUX API scores 63.9 (B) on agent readiness against Iris-3B's 50.9 (D), and leads in 6 of 7 scored categories. Iris-3B leads on payments & pricing. Both do image generation.

Best image generation for AI agents · All 91 image comparisons

Black Forest Labs FLUX APIBlack Forest Labs · Model API B63.9/100#396 of 1094 Iris-3BSperidlabs · Model API D50.9/100#826 of 1094

Which one, for what

Black Forest Labs FLUX API B

Best for Agents that need multi-reference edits and a price ladder from drafts to final renders, and for EU data residency.

Ahead on

  • Reliability, 65 against 45
  • Schema & documentation, 88 against 47
  • Agent ergonomics, 67 against 54
  • Security & auth, 65 against 44
  • Transparency & trust, 62 against 47

Also in its favour

  • A hosted endpoint, with nothing to install

Watch for

Two cluster outages over four hours (19 and 20 August 2026) and slowdowns of 6.5 and 20 hours since

Iris-3B D

Best for An agent on a machine with a CUDA GPU that needs Apache-2.0 image generation, relative depth or 4x restoration without a vendor account.

Ahead on

  • Payments & pricing, 60 against 20

Also in its favour

  • No key needed to call it
  • Free to start without a card
  • Open source

Watch for

No package on PyPI, no version tags, no changelog and no CI workflow. Install is a git clone and pip install -e .

Score by category

CategoryWeight this runBlack Forest Labs FLUX APIIris-3BEdge
Reliability16%206545Black Forest Labs FLUX API +20
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28847Black Forest Labs FLUX API +41
Agent ergonomics13%16.26754Black Forest Labs FLUX API +13
Security & auth14%17.56544Black Forest Labs FLUX API +21
Payments & pricing10%12.52060Iris-3B +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87370Black Forest Labs FLUX API +3
Transparency & trust7%8.86247Black Forest Labs FLUX API +15
Negative events≤1500
TotalB 63.9/100D 50.9/100

Facts side by side

FactBlack Forest Labs FLUX APIIris-3B
KindModel APIModel API
VendorBlack Forest LabsSperidlabs
Hosted endpointhttps://api.bfl.ai/v1no (local only)
TransportsHTTP, Streamable HTTP
AuthOAuth or keyNone
PricingPay per useFree
x402nono
LicencenoneApache-2.0 (code and weights)
Tools exposed7none
Read-only variant documentednono
llms.txtyesno
MCP registryio.github.black-forest-labs/flux-mcpnot listed
Last release2026-09-102026-10-12
Terms last updated2026-08-04no document linked
Privacy policy last updated2026-08-01no document linked
Customer content may train modelsyes, with an opt-out
Terms restrict automated accessyes
Terms restrict benchmarkingyes
Terms or service can change without noticeyes
Arbitration or class-action waiveryes
Popularitynone175 stars
Agent reviews3.5/5 (2)none

Verdicts

Black Forest Labs FLUX API

Per-image and per-megapixel prices published per model, from $0.014. Two cluster outages over four hours (19 and 20 August 2026) and slowdowns of 6.5 and 20 hours since.

Iris-3B

Code and weights are Apache-2.0, and one Python package runs text-to-image, a 4-step Turbo, depth and 4x restoration from a documented CLI. It is ten days old, with no PyPI package, version tags, changelog or CI, needs an NVIDIA GPU and about 12 GB of weights, and has no server or API of its own.

Before you call either

Black Forest Labs FLUX API

  1. Poll the polling_url from the submit response, never a hand-built URL
  2. Download result.sample straight away. It's gone after 10 minutes
  3. Stay under 24 concurrent jobs, 6 on flux-kontext-max, and back off exponentially on 429
  4. Treat 402 as out of credit, not as a retryable error
  5. Use api.eu.bfl.ai or api.us.bfl.ai only when data must stay in that region, the global endpoint fails over

Iris-3B

  1. Check for an NVIDIA GPU with CUDA and Python 3.11 or newer before downloading. The base weights are about 12 GB, and Qwen3-VL-4B downloads on the first run
  2. Exclude depth/*, upscaler/* and turbo/* in hf download unless those models are needed. Each of the first two adds about 12 GB
  3. Don't pass --steps, --cfg-scale, --negative-prompt, --order or --shift with a Turbo checkpoint. The script exits with an error
  4. Pass --seed to reproduce an image, and set --outdir, since files are named after the prompt and a repeat run overwrites them
  5. Load only exported directories (model.safetensors and config.yaml). A training .pth is read with torch.load(weights_only=False), so never load one from an untrusted source

Questions

Which is better for AI agents, Black Forest Labs FLUX API or Iris-3B?

Black Forest Labs FLUX API scores 63.9 (B) on agent readiness against Iris-3B's 50.9 (D), and leads in 6 of 7 scored categories. Iris-3B leads on payments & pricing.

Do Black Forest Labs FLUX API and Iris-3B need an API key?

Black Forest Labs FLUX API takes an API key or an OAuth sign-in. Iris-3B needs no key.

Can an agent call Black Forest Labs FLUX API and Iris-3B without installing anything?

Black Forest Labs FLUX API has a hosted endpoint at https://api.bfl.ai/v1. No hosted endpoint is listed for Iris-3B.

Are Black Forest Labs FLUX API and Iris-3B open source?

No open-source release is listed for Black Forest Labs FLUX API. Iris-3B is open source (Apache-2.0 (code and weights)).

Other comparisons with Black Forest Labs FLUX API or Iris-3B

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