Seedream 5.5 API

Technical Specifications of Seedream 5.5

Important: The 100-round editing capability is demonstrated in successive editing workflows. It should not be interpreted as a guaranteed API session limit or a single-request parameter.

Main Features of Seedream 5.5

• 100-round multi-turn image editing: Seedream 5.5 supports extended editing workflows in which each generated image becomes the input for the next revision. It preserves unedited regions at the pixel level, helping maintain original composition, subject identity, colors, and visual details across repeated modifications.
• Native RGBA transparent image generation: Unlike workflows that require generating an image first and removing its background afterward, Seedream 5.5 directly generates images with alpha channels. It supports full and partial transparency, making it easier to create product cutouts, stickers, character assets, and reusable design elements.
• More realistic image generation: The model improves the rendering of lighting, skin textures, materials, reflections, shadows, and environmental details. It also reduces excessive gloss, overexposure, and unnatural surface textures, producing images with a more natural photographic appearance.
• Improved text rendering and typography: Seedream 5.5 is designed to reproduce complex character shapes and densely arranged small text more accurately. This is particularly valuable for posters, infographics, product packaging, advertisements, newspaper layouts, and multilingual visual content.
• Better consistency across multiple objects: The model can modify specific objects while maintaining their relationships with surrounding elements. Its editing capabilities account for perspective, occlusion, lighting, and shadows, making it useful for evolving interior designs, product compositions, and complex illustrations.
• Professional creative production workflows: Seedream 5.5 targets e-commerce, marketing, film and television, gaming, office productivity, and fashion design. Its combination of image generation, precise editing, and transparent asset creation helps reduce repetitive manual design work.

Source: ByteDance Seed, November 9, 2026.

Benchmark Performance of Seedream 5.5

ByteDance evaluated Seedream 5.5 using MagicArena and experienced image-generation evaluators across six professional production categories:

• E-commerce
• Marketing
• Film and television
• Gaming
• Office productivity
• Fashion design

The evaluation compared image quality and usability against Seedream 5.0 Pro. Seedream 5.5 improved both measurements in all six categories. Its usability rate was more than twice that of Seedream 5.0 Pro in film and television and office productivity.

ByteDance Seed Team

Text Rendering and Image Realism Results

GSB (Good/Same/Bad) measures human preference when comparing image pairs. The +55.62% result represents a positive preference score against the previous version, not a 55.62% increase in image quality.

Seedream 5.5 vs. GPT Image 2.5 Sunburst vs. Nano Banana 2.1

ByteDance also compared Seedream 5.5 with GPT Image 2.5 Sunburst and Nano Banana 2.1.

Its published findings indicate:

• Text structure: Seedream 5.5 leads in both text-to-image and image-to-image evaluations.
• Text-to-image realism: Seedream 5.5 demonstrates a substantial advantage.
• Image-to-image realism: Its published +55.62% GSB score is against Seedream 5.0 Pro, not against the competing models.

No complete numerical competitor score table was published in the announcement. Therefore, a ranking with invented percentages would be misleading.

Best Use Cases for Seedream 5.5

1. E-commerce product photography: Refine product images, modify backgrounds, adjust lighting, and generate reusable transparent product assets.
2. Advertising and marketing design: Create promotional posters, visual campaigns, branded graphics, and text-heavy advertisements.
3. Graphic design and compositing: Generate transparent RGBA assets, stickers, isolated characters, and layered creative elements.
4. Fashion and character design: Modify hairstyles, outfits, accessories, and other specific visual elements while preserving the original composition.
5. Film and game production: Develop visual concepts, environments, character designs, and consistent creative assets through iterative editing.
6. Infographics and editorial content: Generate diagrams, newspaper-style layouts, multilingual illustrations, and images containing dense small text.

Seedream 5.5 vs. Seedream 5.0 Pro vs. GPT Image 2.5 Sunburst vs. Nano Banana 2.1

Which model should you choose?

• Seedream 5.5: Consider it for iterative design, transparent creative assets, image compositions containing text, and professional visual production.
• GPT Image 2.5 Sunburst: Consider it as an alternative for general-purpose image generation and editing.
• Nano Banana 2.1: Consider it for image generation and reference-based editing workflows.

This is a feature-based comparison, not a claim that Seedream 5.5 wins every image-generation task.