--- title: Riverflow 2.5 Fast | Runware Docs url: https://runware.ai/docs/models/sourceful-riverflow-2-5-fast description: Fast production image generation and editing for brand and packaging workflows --- # Riverflow 2.5 Fast Riverflow 2.5 Fast is the speed-focused variant in Sourceful's Riverflow 2.5 family. It supports both text-to-image and image-to-image workflows through the 2.5 generation endpoints, making it suitable for rapid creative iteration, packaging exploration, branded product visuals, and latency-sensitive production pipelines that still need strong visual control. - **ID**: `sourceful:riverflow-2.5@fast` - **Status**: live - **Creator**: Sourceful - **Capabilities**: Text to Image, Image to Image, Edit ## Pricing Pricing starts at $0.021 per image generated. Pricing is dependent on thinking effort (low, medium, high) - **1k . Low**: `$0.021` - **1k . Medium**: `$0.022` - **1k . Fast**: `$0.025` ## Compatibility & Validation `resolution` cannot be used with `width/height`. --- When `settings.backgroundMode` is `solid`, `settings.backgroundColor` is required. --- `width` and `height` must be used together. --- The following dimension combinations are supported: | Configuration | Dimensions | | --- | --- | | `1K (1:1)` | `1024x1024` | | `1K (21:9)` | `1344x576` | | `1K (16:9)` | `1024x576` | | `1K (3:2)` | `1152x768` | | `1K (4:3)` | `1024x768` | | `1K (5:4)` | `960x768` | | `1K (4:5)` | `768x960` | | `1K (3:4)` | `768x1024` | | `1K (2:3)` | `768x1152` | | `1K (9:16)` | `576x1024` | | `2K (1:1)` | `2048x2048` | | `2K (21:9)` | `2688x1152` | | `2K (16:9)` | `2048x1152` | | `2K (3:2)` | `2304x1536` | | `2K (4:3)` | `2048x1536` | | `2K (5:4)` | `1920x1536` | | `2K (4:5)` | `1536x1920` | | `2K (3:4)` | `1536x2048` | | `2K (2:3)` | `1536x2304` | | `2K (9:16)` | `1152x2048` | ## Request Parameters **API Options** Platform-level options for task execution and delivery. ### [taskType](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-tasktype) - **Type**: `string` - **Required**: true - **Value**: `imageInference` Identifier for the type of task being performed ### [taskUUID](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-taskuuid) - **Type**: `string` - **Required**: true - **Format**: `UUID v4` UUID v4 identifier for tracking tasks and matching async responses. Must be unique per task. ### [outputType](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-outputtype) - **Type**: `string` - **Default**: `URL` Image output type. **Allowed values**: `URL` `base64Data` `dataURI` ### [outputFormat](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-outputformat) - **Type**: `string` - **Default**: `JPG` Specifies the file format of the generated output. The available values depend on the task type and the specific model's capabilities. - \`JPG\`: Best for photorealistic images with smaller file sizes (no transparency). - \`PNG\`: Lossless compression, supports high quality and transparency (alpha channel). - \`WEBP\`: Modern format providing superior compression and transparency support. > [!NOTE] > \*\*Transparency\*\*: If you are using features like background removal or LayerDiffuse that require transparency, you must select a format that supports an alpha channel (e.g., \`PNG\`, \`WEBP\`, \`TIFF\`). \`JPG\` does not support transparency. **Allowed values**: `JPG` `PNG` `WEBP` ### [outputQuality](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-outputquality) - **Type**: `integer` - **Min**: `20` - **Max**: `99` - **Default**: `95` Compression quality of the output. Higher values preserve quality but increase file size. ### [webhookURL](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-webhookurl) - **Type**: `string` - **Format**: `URI` Specifies a webhook URL where JSON responses will be sent via HTTP POST when generation tasks complete. For batch requests with multiple results, each completed item triggers a separate webhook call as it becomes available. **Learn more** (1 resource): - [Webhooks](https://runware.ai/docs/platform/webhooks) (platform) ### [deliveryMethod](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-deliverymethod) - **Type**: `string` - **Default**: `sync` Determines how the API delivers task results. **Allowed values**: - `sync` Returns complete results directly in the API response. - `async` Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse. **Learn more** (1 resource): - [Task Polling](https://runware.ai/docs/platform/task-polling) (platform) ### [uploadEndpoint](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-uploadendpoint) - **Type**: `string` - **Format**: `URI` Specifies a URL where the generated content will be automatically uploaded using the HTTP PUT method. The raw binary data of the media file is sent directly as the request body. For secure uploads to cloud storage, use presigned URLs that include temporary authentication credentials. **Common use cases:** - **Cloud storage**: Upload directly to S3 buckets, Google Cloud Storage, or Azure Blob Storage using presigned URLs. - **CDN integration**: Upload to content delivery networks for immediate distribution. ```text // S3 presigned URL for secure upload https://your-bucket.s3.amazonaws.com/generated/content.mp4?X-Amz-Signature=abc123&X-Amz-Expires=3600 // Google Cloud Storage presigned URL https://storage.googleapis.com/your-bucket/content.jpg?X-Goog-Signature=xyz789 // Custom storage endpoint https://storage.example.com/uploads/generated-image.jpg ``` The content data will be sent as the request body to the specified URL when generation is complete. ### [safety](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-safety) - **Path**: `safety.checkContent` - **Type**: `object (2 properties)` Content safety checking configuration for image generation. #### [checkContent](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-safety-checkcontent) - **Path**: `safety.checkContent` - **Type**: `boolean` - **Default**: `false` Enable or disable content safety checking. When enabled, defaults to `fast` mode. #### [mode](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-safety-mode) - **Path**: `safety.mode` - **Type**: `string` - **Default**: `none` Safety checking mode for image generation. **Allowed values**: - `none` Disables checking. - `fast` Performs a single check. ### [ttl](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-ttl) - **Type**: `integer` - **Min**: `60` Time-to-live (TTL) in seconds for generated content. Only applies when `outputType` is `URL`. ### [includeCost](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-includecost) - **Type**: `boolean` - **Default**: `false` Include task cost in the response. ### [numberResults](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-numberresults) - **Type**: `integer` - **Min**: `1` - **Max**: `20` - **Default**: `1` Number of results to generate. Each result uses a different seed, producing variations of the same parameters. **Inputs** Input resources for the task (images, audio, etc). These must be nested inside the \`inputs\` object. ### [referenceImages](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-inputs-referenceimages) - **Path**: `inputs.referenceImages` - **Type**: `array of strings` List of reference images (UUID, URL, Data URI, or Base64). ### [fonts](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-inputs-fonts) - **Path**: `inputs.fonts` - **Type**: `array of objects (2 properties)` Font references containing a font URL and the text to render. #### [text](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-inputs-fonts-text) - **Path**: `inputs.fonts.text` - **Type**: `string` - **Required**: true - **Min**: `1` Text to render with this font. #### [url](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-inputs-fonts-url) - **Path**: `inputs.fonts.url` - **Type**: `string` - **Required**: true - **Format**: `URI` Font file URL. Must be ttf, otf, woff, or woff2. **Core Parameters** Primary parameters that define the task output. ### [model](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-model) - **Type**: `string` - **Required**: true - **Value**: `sourceful:riverflow-2.5@fast` Identifier of the model to use for generation. ### [positivePrompt](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-positiveprompt) - **Type**: `string` - **Required**: true - **Min**: `2` Text prompt describing elements to include in the generated output. ### [width](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-width) - **Type**: `integer` - **Required**: true - **Paired with**: height Width of the generated media in pixels. ### [height](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-height) - **Type**: `integer` - **Required**: true - **Paired with**: width Height of the generated media in pixels. ### [resolution](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-resolution) - **Type**: `string` - **Default**: `1K` Resolution preset for the output. When used with input media, automatically matches the aspect ratio from the input. **Allowed values**: `1K` `2K` **Settings** Technical parameters to fine-tune the inference process. These must be nested inside the \`settings\` object. ### [backgroundColor](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-backgroundcolor) - **Path**: `settings.backgroundColor` - **Type**: `string` Hex color composited when backgroundMode is solid. ### [backgroundMode](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-backgroundmode) - **Path**: `settings.backgroundMode` - **Type**: `string` - **Default**: `original` Background handling mode for the final output. **Allowed values**: - `original` Keep the original background. - `transparent` Remove the background for a transparent result. - `solid` Replace the background with a solid color. ### [enhancePrompt](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-enhanceprompt) - **Path**: `settings.enhancePrompt` - **Type**: `boolean` - **Default**: `false` Enhance the prompt with use-case context before generation. ### [scoringPrompt](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringprompt) - **Path**: `settings.scoringPrompt` - **Type**: `string` - **Min**: `1` Free-text quality rubric used when scoring candidate outputs. ### [scoringRubric](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric) - **Path**: `settings.scoringRubric` - **Type**: `array of objects (8 properties)` Controlled scoring dimensions that replace the default sub-score dimensions for the requested flow. #### [key](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric-key) - **Path**: `settings.scoringRubric.key` - **Type**: `string` - **Required**: true Unique machine-readable dimension key. #### [label](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric-label) - **Path**: `settings.scoringRubric.label` - **Type**: `string` - **Required**: true - **Min**: `1` - **Max**: `80` Short human-readable dimension label. #### [description](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric-description) - **Path**: `settings.scoringRubric.description` - **Type**: `string` - **Required**: true - **Min**: `1` - **Max**: `1000` Judging criteria for this score dimension. #### [weight](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric-weight) - **Path**: `settings.scoringRubric.weight` - **Type**: `float` - **Required**: true Scoring weight. Normalized internally, so weights need not sum to 1. #### [passingScore](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric-passingscore) - **Path**: `settings.scoringRubric.passingScore` - **Type**: `float` - **Min**: `0` - **Max**: `1` Minimum score this dimension must reach. #### [scoreGuidance](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric-scoreguidance) - **Path**: `settings.scoringRubric.scoreGuidance` - **Type**: `array of objects (2 properties)` Scoring anchors that define what the normalized scale means. ##### [score](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric-scoreguidance-score) - **Path**: `settings.scoringRubric.scoreGuidance.score` - **Type**: `float` - **Required**: true - **Min**: `0` - **Max**: `1` Normalized score anchor. ##### [description](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-scoringrubric-scoreguidance-description) - **Path**: `settings.scoringRubric.scoreGuidance.description` - **Type**: `string` - **Required**: true - **Min**: `1` - **Max**: `500` What this score anchor means for the judge. ### [thinkingLevel](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#request-settings-thinkinglevel) - **Path**: `settings.thinkingLevel` - **Type**: `string` - **Default**: `medium` Controls the depth of internal reasoning the model performs before generating a response. **Allowed values**: `low` `medium` `high` ## Response Parameters ### [taskType](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-tasktype) - **Type**: `string` - **Required**: true - **Value**: `imageInference` Type of the task. ### [taskUUID](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-taskuuid) - **Type**: `string` - **Required**: true - **Format**: `UUID v4` UUID of the task. ### [imageUUID](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-imageuuid) - **Type**: `string` - **Required**: true - **Format**: `UUID v4` UUID of the output image. ### [imageURL](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-imageurl) - **Type**: `string` - **Format**: `URI` URL of the output image. ### [imageBase64Data](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-imagebase64data) - **Type**: `string` Base64-encoded image data. ### [imageDataURI](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-imagedatauri) - **Type**: `string` - **Format**: `URI` Data URI of the output image. ### [seed](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-seed) - **Type**: `integer` The seed used for generation. If none was provided, shows the randomly generated seed. ### [NSFWContent](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-nsfwcontent) - **Type**: `boolean` Flag indicating if NSFW content was detected. ### [cost](https://runware.ai/docs/models/sourceful-riverflow-2-5-fast#response-cost) - **Type**: `float` Task cost in USD. Present when `includeCost` is set to `true` in the request.