black-forest-labs-flux

Produce images with Black Forest Labs FLUX

Use this evidence notation throughout your work:

• [Documented] means BFL documentation, a BFL model card/repository, BFL legal terms, or a BFL-authored paper states the fact.
• [Inference] means a conclusion follows from documented facts but BFL does not state it directly.
• [Heuristic] means production advice to validate against actual outputs.

Treat all endpoint names, limits, prices, licenses, and terms as volatile. The facts below were verified 2026-07-09. Recheck the current BFL API reference, release notes, model card, and governing license before a consequential run.

Keep the execution surfaces separate

Identify the surface before selecting parameters or stating rights.

1. BFL direct API — requests go to an official api.bfl.ai endpoint with an x-key. BFL defines the request schema, moderation, billing, asynchronous result contract, and service terms. [Documented: D1, D2, D9]
2. Third-party hosted gateway — the gateway, not BFL's direct API, defines model slugs, accepted parameters, retention, moderation, pricing, and version pinning. Never assume a BFL field or limit works unchanged. Verify that provider's current documentation and contract. [Inference]
3. Local/open-weight deployment — weights and inference run on infrastructure under the checkpoint's own license. There is no automatic BFL API moderation, retention policy, or signed-result URL. Implement filtering, provenance, storage controls, and capacity planning yourself. [Documented: D10, D11]

Do not call every downloadable FLUX checkpoint “open source.” FLUX.2 [klein] 4B is Apache-2.0; FLUX.2 [klein] 9B and FLUX.2 [dev] are downloadable/open-weight but governed by the FLUX Non-Commercial License unless a commercial weights license applies. [Documented: D10]

Select the family deliberately

Current FLUX.2 paths

Need	Choose	Surface and consequential facts
Most production generation/editing	FLUX.2 [pro]	BFL's recommended starting point. Direct endpoints include mutable flux-2-pro-preview and pinned flux-2-pro. Up to 8 references through the API and 10 in the BFL playground. [Documented: D1, D2]
Hardest edit, strongest adherence, highest final quality	FLUX.2 [max]	Direct API/Playground, up to 8 API references. It is the FLUX.2 path with grounding search. Use only when that quality or current-context feature justifies its cost. [Documented: D1, D2]
Typography, small-detail preservation, tunable sampling	FLUX.2 [flex]	Direct API. Exposes guidance 1.5–10 and steps 1–50; supports prompt upsampling and up to 8 API references. Higher guidance can trade realism for adherence. [Documented: D1, D2]
Latency-sensitive preview, interactive tool, high volume	FLUX.2 [klein] 4B or 9B	Direct API and downloadable weights; up to 4 references. No prompt upsampling, so write complete prompts. 4B is Apache-2.0; 9B is FLUX NCL unless separately licensed. [Documented: D1, D10]
Local customization or research with full sampling control	FLUX.2 [dev] or a [klein] Base checkpoint	Local/open-weight, not the BFL public API. BFL recommends at most 6 references for [dev]. Distilled klein is a short-step production path; Base variants retain full training signal for fine-tuning and diversity. Verify the exact checkpoint license. [Documented: D1, D10]