Seedream 4.0

ByteDance Seed · Sep 2025 · Proprietary (API only) · site

ByteDance's closed-weights flagship — unified generation + editing with native 4K output.

What it is

Seedream 4.0 is ByteDance Seed's image flagship, announced in September 2025. Unlike the other entries on this list, it's closed-weights and API-only. It merges generation and editing into a single unified architecture, supports text-to-image up to 4K resolution, and handles batch multi-input/multi-output workflows. ByteDance cites top rankings on their internal MagicBench and on the third-party Artificial Analysis Image Arena at release.

Method
Text → Image
Max res
4K
Speed
Standard (5–15s)

Generated with Seedream 4.0

No public samples for Seedream 4.0 yet.

Honest take

Strengths & limitations

Strengths
  • +Native 4K output — higher than most open competitors
  • +Unified generation + editing architecture
  • +Batch multi-in / multi-out processing
  • +High ranking on Artificial Analysis Image Arena at release
Limitations
  • Closed weights — API-only, no self-hosting or fine-tuning
  • Pricing and availability not publicly documented on the landing page

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