--- title: FLUX.2 [flex] description: FLUX.2 [flex] is Black Forest Labs' fine-grained control variant of FLUX.2 — exposes tunable inference steps, guidance, and prompt upsampling for typography-heavy and production workflows. image: https://developers.cloudflare.com/dev-products-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/ai/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) ![Black Forest Labs logo](https://developers.cloudflare.com/_astro/blackforestlabs.Ccs-Y4-D.svg) # FLUX.2 \[flex\] Text-to-Image • Black Forest Labs `black-forest-labs/flux-2-flex` FLUX.2 \[flex\] is Black Forest Labs' fine-grained control variant of FLUX.2 — exposes tunable inference steps, guidance, and prompt upsampling for typography-heavy and production workflows. | Model Info | | | ----------------- | ------------------------------------------------------------------------------------------------------------------------------- | | Terms and License | [link ↗](https://blackforestlabs.ai/terms-of-service/) | | More information | [link ↗](https://blackforestlabs.ai/) | | Pricing | [View pricing in the Cloudflare dashboard ↗](https://dash.cloudflare.com/?to=/:account/ai/models/black-forest-labs/flux-2-flex) | ## Usage * [ TypeScript ](#tab-panel-330) * [ cURL ](#tab-panel-331) TypeScript ``` const response = await env.AI.run( 'black-forest-labs/flux-2-flex', { prompt: "Samsung Galaxy S25 Ultra product advertisement, 'Ultra-strong titanium' headline, close-up of phone edge showing titanium frame, dark gradient background, clean minimalist tech aesthetic", },)console.log(response) ``` Terminal window ``` curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/run \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --header "Content-Type: application/json" \ --data '{ "model": "black-forest-labs/flux-2-flex", "input": { "prompt": "Samsung Galaxy S25 Ultra product advertisement, '\''Ultra-strong titanium'\'' headline, close-up of phone edge showing titanium frame, dark gradient background, clean minimalist tech aesthetic" }}' ``` * [ Output ](#tab-panel-328) * [ Raw response ](#tab-panel-329) ![Typography & Design](https://examples.aig.cloudflare.com/black-forest-labs/flux-2-flex/typography-design.jpeg) ``` { "state": "Completed", "result": { "image": "https://examples.aig.cloudflare.com/black-forest-labs/flux-2-flex/typography-design.jpeg" }, "gatewayMetadata": { "keySource": "Unified" }} ``` ## Examples **High Detail Generation** — Crank steps and guidance for maximum detail when latency is not the priority * [ TypeScript ](#tab-panel-334) * [ cURL ](#tab-panel-335) TypeScript ``` const response = await env.AI.run( 'black-forest-labs/flux-2-flex', { prompt: 'A detailed oil painting portrait of a Renaissance nobleman with intricate lace collar', guidance: 7.5, steps: 50, },)console.log(response) ``` Terminal window ``` curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/run \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --header "Content-Type: application/json" \ --data '{ "model": "black-forest-labs/flux-2-flex", "input": { "prompt": "A detailed oil painting portrait of a Renaissance nobleman with intricate lace collar", "guidance": 7.5, "steps": 50 }}' ``` * [ Output ](#tab-panel-332) * [ Raw response ](#tab-panel-333) ![High Detail Generation](https://examples.aig.cloudflare.com/black-forest-labs/flux-2-flex/high-detail-generation.jpeg) ``` { "state": "Completed", "result": { "image": "https://examples.aig.cloudflare.com/black-forest-labs/flux-2-flex/high-detail-generation.jpeg" }, "gatewayMetadata": { "keySource": "Unified" }} ``` **Fast Draft** — Fast draft with prompt upsampling disabled — preserves the literal prompt * [ TypeScript ](#tab-panel-338) * [ cURL ](#tab-panel-339) TypeScript ``` const response = await env.AI.run( 'black-forest-labs/flux-2-flex', { prompt: 'A simple line sketch of a mountain landscape', prompt_upsampling: false, steps: 10 },)console.log(response) ``` Terminal window ``` curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/run \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --header "Content-Type: application/json" \ --data '{ "model": "black-forest-labs/flux-2-flex", "input": { "prompt": "A simple line sketch of a mountain landscape", "prompt_upsampling": false, "steps": 10 }}' ``` * [ Output ](#tab-panel-336) * [ Raw response ](#tab-panel-337) ![Fast Draft](https://examples.aig.cloudflare.com/black-forest-labs/flux-2-flex/fast-draft.jpeg) ``` { "state": "Completed", "result": { "image": "https://examples.aig.cloudflare.com/black-forest-labs/flux-2-flex/fast-draft.jpeg" }, "gatewayMetadata": { "keySource": "Unified" }} ``` ## Parameters * [ Input ](#tab-panel-340) * [ Output ](#tab-panel-341) prompt `string`requiredText prompt for image generation or editing. seed `integer`minimum: \-9007199254740991maximum: 9007199254740991Optional seed for reproducible generation. width `integer`minimum: 64maximum: 9007199254740991Width of the generated image in pixels (minimum 64). Omit to let BFL pick. height `integer`minimum: 64maximum: 9007199254740991Height of the generated image in pixels (minimum 64). Omit to let BFL pick. safety\_tolerance `integer`minimum: 0maximum: 5Tolerance for input/output moderation. 0 is the strictest, 5 the most permissive. Defaults to 2. output\_format `string`enum: jpeg, png, webpOutput image format. Defaults to jpeg. ▶input\_images\[\] `array`maxItems: 8Up to 8 reference images for editing or multi-image composition. Each entry is an HTTPS URL or a data:image/...;base64,... URI. prompt\_upsampling `boolean`Whether BFL should expand short prompts before generation. Defaults to true on flex. guidance `number`minimum: 1.5maximum: 10Classifier-free guidance scale (1.5–10). Higher values follow the prompt more strictly at the cost of realism. steps `integer`minimum: 1maximum: 50Number of denoising steps (1–50). Higher steps yield more detail at the cost of latency. image `string`format: uriURL to the generated image ## API Schemas (Raw) Input [ ](https://developers.cloudflare.com/ai/models/black-forest-labs/flux-2-flex/schema-input.json "Open") [ ](https://developers.cloudflare.com/ai/models/black-forest-labs/flux-2-flex/schema-input.json "Download") Output [ ](https://developers.cloudflare.com/ai/models/black-forest-labs/flux-2-flex/schema-output.json "Open") [ ](https://developers.cloudflare.com/ai/models/black-forest-labs/flux-2-flex/schema-output.json "Download") ```json {"@context":"https://schema.org","@type":"TechArticle","@id":"https://developers.cloudflare.com/ai/models/black-forest-labs/flux-2-flex/#page","headline":"FLUX.2 [flex] (Black Forest Labs) · Cloudflare AI docs · Cloudflare AI docs","description":"FLUX.2 \\[flex] is Black Forest Labs' fine-grained control variant of FLUX.2 — exposes tunable inference steps, guidance, and prompt upsampling for typography-heavy and production workflows.","url":"https://developers.cloudflare.com/ai/models/black-forest-labs/flux-2-flex/","inLanguage":"en","image":"https://developers.cloudflare.com/dev-products-preview.png","publisher":{"@type":"Organization","name":"Cloudflare","url":"https://www.cloudflare.com/"},"isPartOf":{"@type":"WebSite","@id":"https://developers.cloudflare.com/#website","name":"Cloudflare Docs","url":"https://developers.cloudflare.com/"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/ai/","name":"AI"}},{"@type":"ListItem","position":3,"item":{"@id":"/ai/models/","name":"Models"}}]} ```