Seedream 4.0 API from ByteDance is a next-generation model that combines text-to-image, image-to-image, and editing with batch consistency, high speed, and professional-quality outputs.

Model Type:
Pricing: Seedream V4: 5 credits per image (~$0.025). The price is independent of image resolution and is solely determined by the final number of images returned. The number of images depends on the quantity specified in the prompt and the maximum value set by max_images, both of which jointly determine the final count. High-tier top-ups include +10% bonus credits. Effective pricing is approximately 10% lower than the above rates.
Input

The text prompt used to edit the image

0/5000

Click to upload or drag and drop

Supported formats: JPEG, PNG, WEBP Maximum file size: 30MB; Maximum files: 10

List of URLs of input images for editing. Presently, up to 10 image inputs are allowed.

The size of the generated image.

Final image resolution is determined by combining image_size (aspect ratio) and image_resolution (pixel scale). For example, choosing 4:3 + 4K gives 4096 × 3072px

Set this value (1–6) to cap how many images a single generation run can produce in one set—because they’re created in one shot rather than separate requests, you must also state the exact number you want in the prompt so both settings align.

Random seed to control the stochasticity of image generation.

A configurable parameter. Defaults to true in the Playground.

There is no guarantee that everything can be filtered out; if you are not satisfied with the results, you will need to make your own arrangements.
Output
output typeimage
Generated output
Examples

Explore different use cases and parameter configurations

README

Complete guide to using Seedream 4.0

Seedream 4.0 API Free Online Test

Original image
Bytedance Seedream 4.0 API Introduction
Precise Instruction Editing
Strong Feature Preservation
Deep Intent Understanding
Multi-Image Input and Output
Ultra-Fast and Ultra-HD Generation
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Seedream 4.0 API is Bytedance’s advanced AI model that supports text-to-image, image-to-image, and image editing. On Kie AI, you can test Bytedance Seedream 4.0 API online for free.

You can start by getting an API key from Kie AI, choose between Seedream 4.0 Text to Image API, Image-to-Image API, or Image Editing API, then enter prompts or upload images to generate results instantly.

Yes. Kie AI offers free online testing for Seedream 4 API, so developers can explore its features without setup or upfront cost.

Yes. Kie AI provides flexible and transparent plans for Seedream4 API, making it more affordable than most high-cost providers.

You can get a free Seedream API Key by signing up on Kie AI. After registration, go to the API dashboard, select Bytedance Seedream 4.0 API, and request your free key. The free plan allows you to test Seedream 4.0 Text to Image API, Image-to-Image API, and Image Editing API online without setup.

Seedream 4.0 API is faster (2K images in under 1.8s), supports batch consistency, and offers precise editing. Google NanoBanana API focuses more on character consistency and detailed prompt following. Kie AI provides access to both APIs, so you can test them free online and compare results directly.