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.

Complete technical specification for integration
Ready-to-use code snippets for common workflows
API Options
Platform-level options for task execution and delivery.
taskType
stringrequiredvalue: imageInferenceIdentifier for the type of task being performed
taskUUID
stringrequiredUUID v4UUID v4 identifier for tracking tasks and matching async responses. Must be unique per task.
outputType
stringdefault: URLImage output type.
Allowed values3 values
outputFormat
stringrequired*default: JPGSpecifies 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.
**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 values3 values
outputQuality
integermin: 20max: 99default: 95Compression quality of the output. Higher values preserve quality but increase file size.
webhookURL
stringURISpecifies 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 more1 resource
- WebhooksPLATFORM
- Webhooks
deliveryMethod
stringdefault: syncDetermines how the API delivers task results.
Allowed values2 values
- Returns complete results directly in the API response.
- Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse.
Learn more1 resource
- Task PollingPLATFORM
uploadEndpoint
stringURISpecifies 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.
// 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.jpgThe content data will be sent as the request body to the specified URL when generation is complete.
safety
objectContent safety checking configuration for image generation.
Properties1 property
safety»checkContentcheckContent
booleandefault: falseEnable or disable content safety checking.
ttl
integermin: 60Time-to-live (TTL) in seconds for generated content. Only applies when
outputTypeisURL.
includeCost
booleandefault: falseInclude task cost in the response.
numberResults
integermin: 1max: 20default: 1Number 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.
inputs object.inputs»referenceImagesreferenceImages
array of stringsmin items: 1max items: 4List of reference images (UUID, URL, Data URI, or Base64).
inputs»fontsfonts
array of objectsmax items: 2Font references containing a font URL and the text to render.
Core Parameters
Primary parameters that define the task output.
model
stringrequiredvalue: sourceful:riverflow-2.5@fastIdentifier of the model to use for generation.
Learn more3 resources
positivePrompt
stringrequiredmin: 2max: 24000Text prompt describing elements to include in the generated output.
Learn more1 resource
- PromptsLEARN
- Prompts
Width of the generated media in pixels.
Learn more2 resources
Height of the generated media in pixels.
Learn more2 resources
resolution
stringdefault: 1KResolution preset for the output. When used with input media, automatically matches the aspect ratio from the input.
Allowed values2 values
Settings
Technical parameters to fine-tune the inference process. These must be nested inside the settings object.
settings object.settings»backgroundColorbackgroundColor
stringHex color composited when backgroundMode is solid.
settings»backgroundModebackgroundMode
stringdefault: originalBackground handling mode for the final output.
Allowed values3 values
- Keep the original background.
- Remove the background for a transparent result.
- Replace the background with a solid color.
settings»enhancePromptenhancePrompt
booleandefault: falseEnhance the prompt with use-case context before generation.
settings»scoringPromptscoringPrompt
stringmin: 1Free-text quality rubric used when scoring candidate outputs.
settings»scoringRubricscoringRubric
array of objectsmin items: 1max items: 8Controlled scoring dimensions that replace the default sub-score dimensions for the requested flow.
Properties6 properties
settings»scoringRubric»keykey
stringrequiredUnique machine-readable dimension key.
settings»scoringRubric»labellabel
stringrequiredmin: 1max: 80Short human-readable dimension label.
settings»scoringRubric»descriptiondescription
stringrequiredmin: 1max: 1000Judging criteria for this score dimension.
settings»scoringRubric»weightweight
floatrequiredScoring weight. Normalized internally, so weights need not sum to 1.
settings»scoringRubric»passingScorepassingScore
floatmin: 0max: 1Minimum score this dimension must reach.
settings»scoringRubric»scoreGuidancescoreGuidance
array of objectsmax items: 5Scoring anchors that define what the normalized scale means.
Properties2 properties
settings»scoringRubric»scoreGuidance»scorescore
floatrequiredmin: 0max: 1Normalized score anchor.
settings»scoringRubric»scoreGuidance»descriptiondescription
stringrequiredmin: 1max: 500What this score anchor means for the judge.
settings»thinkingLevelthinkingLevel
stringdefault: mediumControls the depth of internal reasoning the model performs before generating a response.
Allowed values3 values