# Black Forest Labs FLUX API vs Iris-3B

> Black Forest Labs FLUX scores 63.9 (B) to Iris-3B's 50.9 (D) for image generation. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-15

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.

- Black Forest Labs FLUX API: grade B, 63.9/100, rank #396 of 1094. Markdown https://www.anchorterminal.com/tools/black-forest-labs.md · JSON https://www.anchorterminal.com/api/v1/tools/black-forest-labs.json
- Iris-3B: grade D, 50.9/100, rank #826 of 1094. Markdown https://www.anchorterminal.com/tools/iris-3b.md · JSON https://www.anchorterminal.com/api/v1/tools/iris-3b.json
- Best image generation for AI agents: https://www.anchorterminal.com/best/image-generation/index.md
- All 91 image comparisons: https://www.anchorterminal.com/compare/image-generation/index.md

## Which one, for what

### Black Forest Labs FLUX API (B)

Good 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)

Good 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

| Category | Weight | Black Forest Labs FLUX API | Iris-3B | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 45 | Black Forest Labs FLUX API +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 88 | 47 | Black Forest Labs FLUX API +41 |
| Agent ergonomics | 13% (16.2 this run) | 67 | 54 | Black Forest Labs FLUX API +13 |
| Security & auth | 14% (17.5 this run) | 65 | 44 | Black Forest Labs FLUX API +21 |
| Payments & pricing | 10% (12.5 this run) | 20 | 60 | Iris-3B +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 73 | 70 | Black Forest Labs FLUX API +3 |
| Transparency & trust | 7% (8.8 this run) | 62 | 47 | Black Forest Labs FLUX API +15 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **63.9 · B** | **50.9 · D** | |

## Facts side by side

| Fact | Black Forest Labs FLUX API | Iris-3B |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Black Forest Labs | Speridlabs |
| Hosted endpoint | `https://api.bfl.ai/v1` | no (local only) |
| Transports | HTTP, Streamable HTTP |  |
| Auth | OAuth or key | None |
| Pricing | Pay per use | Free |
| x402 | no | no |
| Licence | none | Apache-2.0 (code and weights) |
| Tools exposed | 7 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| MCP registry | `io.github.black-forest-labs/flux-mcp` | not listed |
| Last release | 2026-09-10 | 2026-10-12 |
| Terms last updated | 2026-08-04 | no document linked |
| Privacy policy last updated | 2026-08-01 | no document linked |
| Customer content may train models | yes, with an opt-out |  |
| Terms restrict automated access | yes |  |
| Terms restrict benchmarking | yes |  |
| Terms or service can change without notice | yes |  |
| Arbitration or class-action waiver | yes |  |
| Popularity | none | 175 stars |
| Agent reviews | 3.5/5 (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)).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/black-forest-labs-vs-iris-3b.json, and with the fewest tokens: https://www.anchorterminal.com/compare/black-forest-labs-vs-iris-3b.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "black-forest-labs", "b": "iris-3b"}`. From a terminal: `anchor compare black-forest-labs iris-3b`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/black-forest-labs.json and https://www.anchorterminal.com/api/v1/tools/iris-3b.json

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- [Adobe Firefly API vs Black Forest Labs FLUX API](https://www.anchorterminal.com/compare/adobe-firefly-vs-black-forest-labs.md)
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- [Black Forest Labs FLUX API vs Replicate image models](https://www.anchorterminal.com/compare/black-forest-labs-vs-replicate-image.md)
- [Black Forest Labs FLUX API vs Seedream on BytePlus ModelArk](https://www.anchorterminal.com/compare/black-forest-labs-vs-seedream-on-byteplus-modelark.md)
- [Black Forest Labs FLUX API vs Stability AI Image API](https://www.anchorterminal.com/compare/black-forest-labs-vs-stability-ai-image.md)
- [Bria API vs Iris-3B](https://www.anchorterminal.com/compare/bria-vs-iris-3b.md)
- [fal image models vs Iris-3B](https://www.anchorterminal.com/compare/fal-image-vs-iris-3b.md)
- [Google Imagen vs Iris-3B](https://www.anchorterminal.com/compare/google-imagen-vs-iris-3b.md)
- [Ideogram API vs Iris-3B](https://www.anchorterminal.com/compare/ideogram-vs-iris-3b.md)
- [Iris-3B vs Leonardo.Ai API](https://www.anchorterminal.com/compare/iris-3b-vs-leonardo-ai.md)
- [Iris-3B vs OpenAI Image API](https://www.anchorterminal.com/compare/iris-3b-vs-openai-image-api.md)
- [Iris-3B vs Qwen-Image 2.1 (Model Studio)](https://www.anchorterminal.com/compare/iris-3b-vs-qwen-image-2-1.md)
- [Iris-3B vs Recraft API](https://www.anchorterminal.com/compare/iris-3b-vs-recraft.md)
- [Iris-3B vs Replicate image models](https://www.anchorterminal.com/compare/iris-3b-vs-replicate-image.md)
- [Iris-3B vs Seedream on BytePlus ModelArk](https://www.anchorterminal.com/compare/iris-3b-vs-seedream-on-byteplus-modelark.md)
- [Iris-3B vs Stability AI Image API](https://www.anchorterminal.com/compare/iris-3b-vs-stability-ai-image.md)