Models
Sourceful
Riverflow 2 Fast Preview

Sourceful

Riverflow 2 Fast Preview

Name: Riverflow 2 Fast Preview
Brand: Sourceful
Price: 0.03 USD
Availability: InStock

AI Image Editing Model

Image

Sourceful's lightweight Riverflow 2 variant for fast workflows and lower cost, combining unified text-to-image generation with precise editing capabilities

Try Model

1024 x 1024

Max Resolution

Supported Modes

Image Edit

Active

Details

Model ID

riverflow-2-fast-preview

Also known as: riverflow-2-fast

Creator

Sourceful

Family

riverflow

Max Input Images

Ready to integrate?

Access riverflow-2-fast-preview via our unified API.

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Available at 1 provider

Starting from

$0.030 /image via Runware

Prices shown are in USD

Full pricing details

Providers & Pricing (1)

Riverflow 2 Fast Preview is available exclusively through Runware, starting at $0.03/image.

Runware

runware/riverflow-2-fast-preview

Provider Model ID: sourceful:2@2

$0.030 /image

View pricing details

riverflow-2-fast API OpenAI-compatible

Integrate Riverflow 2 Fast Preview into your application via Lumenfall's OpenAI-compatible API to programmatically generate images and perform professional-grade image edits.

Base URL

https://api.lumenfall.ai/openai/v1

Model

riverflow-2-fast-preview

Code Examples

Image Edit

/v1/images/edits

curl -X POST \

  https://api.lumenfall.ai/openai/v1/images/edits \

  -H "Authorization: Bearer $LUMENFALL_API_KEY" \

  -F "model=riverflow-2-fast-preview" \

  -F "[email protected]" \

  -F "prompt=Add a starry night sky to this image" \

  -F "size=1024x1024"

# Response:

# { "created": 1234567890, "data": [{ "url": "https://...", "revised_prompt": "..." }] }

import OpenAI from 'openai';

import fs from 'fs';

const client = new OpenAI({

  apiKey: 'YOUR_API_KEY',

  baseURL: 'https://api.lumenfall.ai/openai/v1'

});

const response = await client.images.edit({

  model: 'riverflow-2-fast-preview',

  image: fs.createReadStream('source.png'),

  prompt: 'Add a starry night sky to this image',

  size: '1024x1024'

});

// { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }

console.log(response.data[0].url);

from openai import OpenAI

client = OpenAI(

    api_key="YOUR_API_KEY",

    base_url="https://api.lumenfall.ai/openai/v1"

response = client.images.edit(

    model="riverflow-2-fast-preview",

    image=open("source.png", "rb"),

    prompt="Add a starry night sky to this image",

    size="1024x1024"

# { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }

print(response.data[0].url)

Parameter Reference

Required Supported Not available

Core Parameters

Parameter	Type	Description	Modes
`prompt`	string	Required. Edit instruction for the image	Edit

Size & Layout

Parameter	Type	Description	Modes
`size`	string	Image dimensions as WxH pixels (e.g. "1024x1024") or aspect ratio (e.g. "16:9") WxH determines both shape and scale (aspect_ratio and resolution are ignored when size is provided). W:H format is equivalent to aspect_ratio.	Edit
`aspect_ratio`	string	Aspect ratio of the output image (e.g. "16:9", "1:1") Controls shape independently of scale. Use with resolution to control both. If size is also provided, size takes precedence. Any ratio is accepted and mapped to the nearest supported value.	Edit
`resolution`	string	Output resolution tier (e.g. "1K", "4K") Controls scale independently of shape. Higher tiers produce larger images and cost more. If size is also provided, size takes precedence for scale. Any tier is accepted and mapped to the nearest supported value.	Edit

size

Exact pixel dimensions

"1920x1080"

aspect_ratio

Shape only, default scale

"16:9"

resolution

Scale tier, preserves shape

"1K"

Priority when combined

size › aspect_ratio + resolution › aspect_ratio › resolution

size is most specific and always wins. aspect_ratio and resolution control shape and scale independently.

How matching works

Shape matching – we pick the closest supported ratio. Ask for 7:1 on a model with 4:1 and 8:1, you get 8:1.

Scale matching – providers use different tier formats: K tiers (0.5K 1K 2K 4K) or megapixel tiers (0.25 1). If the exact tier isn't available, you get the nearest one.

Dimension clamping – if a model has pixel limits, we clamp dimensions to fit and keep the aspect ratio intact.

Media Inputs

Parameter	Type	Description	Modes
`image`	file	Required. Input image(s) to edit Supports PNG, JPEG, WebP.	Edit

Output & Format

Parameter	Type	Description	Modes
`response_format`	string	How to return the image `url` `b64_json` Default: `"url"`	Edit
`output_format`	string	Output image format `png` `jpeg` `gif` `webp` `avif` Gateway converts to requested format if provider doesn't support it natively.	Edit
`output_compression`	integer	Compression level for lossy formats (JPEG, WebP, AVIF)	Edit
`n`	integer	Number of images to generate Default: `1` Gateway generates multiple images in parallel even if provider only supports 1.	Edit

Parameter Normalization

How we handle parameters across different providers

Not every provider speaks the same language. When you send a parameter, we handle it in one of four ways depending on what the model supports:

Behavior	What happens	Example
`passthrough`	Sent as-is to the provider	style, quality
`renamed`	Same value, mapped to the field name the provider expects	prompt
`converted`	Transformed to the provider's native format	size
`emulated`	Works even if the provider has no concept of it	n, response_format

Parameters we don't recognize pass straight through to the upstream API, so provider-specific options still work.

Full API Reference Authentication, endpoints, and more

Gallery

View all 4 images

Riverflow 2 Fast Preview FAQ

How much does Riverflow 2 Fast Preview cost?

Riverflow 2 Fast Preview starts at $0.03 per image through Lumenfall. Pricing varies by provider. Lumenfall does not add any markup to provider pricing.

How do I use Riverflow 2 Fast Preview via API?

You can use Riverflow 2 Fast Preview through Lumenfall's OpenAI-compatible API. Send requests to the unified endpoint with model ID "riverflow-2-fast-preview". Code examples are available in Python, JavaScript, and cURL.

Which providers offer Riverflow 2 Fast Preview?

Riverflow 2 Fast Preview is available through Runware on Lumenfall. Lumenfall automatically routes requests to the best available provider.

What is the maximum resolution for Riverflow 2 Fast Preview?

Riverflow 2 Fast Preview supports images up to 1024x1024 resolution.

Overview

Riverflow 2 Fast Preview is a lightweight image generation model developed by Sourceful, designed specifically for rapid prototyping and low-latency iteration. It functions as an optimized variant of the standard Riverflow 2 architecture, balancing computational efficiency with high-fidelity output. The model is distinctive for its dual-mode capability, allowing users to perform both initial text-to-image generation and subsequent precise image editing within a single, unified framework.

Strengths

Low-Latency Generation: Optimized for speed, making it suitable for real-time applications, live previews, and high-frequency drafting sessions where standard models would be too slow.
Contextual Image Editing: Unlike models that focus solely on generation, this model handles image-to-image tasks and localized edits while maintaining the stylistic consistency of the original input.
Semantic Alignment: Demonstrates strong adherence to complex text prompts, ensuring that the visual elements generated accurately reflect descriptive adjectives and spatial relationships.
Resource Efficiency: Provides a cost-effective alternative for high-volume workflows ($0.03 starting price) without the heavy compute requirements of larger diffusion models.

Limitations

Fine Detail Resolution: As a “Fast Preview” variant, it may lack the intricate micro-textures and hyper-realistic skin or surface details found in the full-scale Riverflow 2 model.
Complex Text Rendering: While proficient at object placement, the model may struggle with rendering long strings of legible text or very small, complex typographical elements within an image.
Compositional Stability: In highly crowded scenes with many subjects, the model may occasionally introduce anatomical inconsistencies or overlapping artifacts compared to larger, slower models.

Technical Background

Riverflow 2 Fast Preview belongs to the Riverflow family of models, characterized by an architecture that integrates text-to-image and image-to-image modalities into a single pipeline. The training approach focuses on distillation and weight optimization to reduce inference steps while preserving the latent space’s expressive power. This allows the model to process both text and image inputs natively, facilitating seamless transitions between creative generation and iterative refinement.

Best For

Rapid Prototyping: Ideal for designers and developers who need to generate a high volume of concepts or “mood board” assets quickly.
Interactive Applications: Suitable for UI/UX environments where users expect near-instant visual feedback based on prompt changes.
Iterative Editing Workflows: Effective for tasks where an initial image needs constant, minor adjustments to color, composition, or specific objects.

Riverflow 2 Fast Preview is available for testing and integration through Lumenfall’s unified API and interactive playground, allowing you to compare its performance against other models in the Riverflow family.

Try Riverflow 2 Fast Preview in Playground

Generate images with custom prompts — no API key needed.

Open Playground