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Documentation Index

Fetch the complete documentation index at: https://docs.apiyi.com/llms.txt

Use this file to discover all available pages before exploring further.

This page lists all Seedream versions still callable on APIYI. The three versions are active simultaneously, with fully compatible parameters — switch by changing only the model field. For the latest version and a general introduction, see Seedream Overview.

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Versions at a Glance

Version IDRelease Date (UTC+8)APIYI PriceStatusRecommended Use
seedream-5-0-2601282026-01-28$0.035 / image✅ Recommended (latest)Best overall experience, text rendering, png output
seedream-4-5-2511282025-11-28$0.04 / image✅ Recommended4K + strongest text rendering (posters, ads)
seedream-4-0-2508282025-08-28$0.03 / image🟡 Maintained4K + best price, only version supporting prompt fast mode
seedream-5-0-260128 can also be invoked with the alias seedream-5-0-lite-260128 — the official docs accept both model_id strings, with identical behavior.

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Per-version Specs

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seedream-5-0-260128 (5.0-lite)

  • Release date: 2026-01-28 (UTC+8)
  • APIYI price: $0.035 / image (≈ ¥0.245 list)
  • Resolution tiers: 2K / 3K (no 4K)
  • Output format: png / jpeg (only version with png output)
  • Prompt optimization: standard
  • Highlights:
    • Best overall experience; the most mature implementation of multi-image fusion / editing / batch sequence
    • Only version supporting png output (and therefore transparent backgrounds)
    • Mature streaming output (stream: true)
  • Known limits:
    • Resolution capped at 3K (~3072×3072). For 4K assets, use 4.5 / 4.0
  • Official docs: docs.byteplus.com/en/docs/ModelArk/1824121

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seedream-4-5-251128

  • Release date: 2025-11-28 (UTC+8)
  • APIYI price: $0.04 / image (≈ ¥0.28 list)
  • Resolution tiers: 2K / 4K
  • Output format: jpeg
  • Prompt optimization: standard
  • Highlights:
    • 1.2B-parameter unified generation-editing architecture
    • Text rendering breakthrough: small text remains crisp — best in class for posters, ads, UI screenshots
    • Multi-image fusion explicitly supports up to 10 reference images
    • Editing preserves lighting, tone, and natural facial detail
  • Known limits:
    • jpeg output only (no png, no transparency)
  • News article: Seedream 4.5 launch

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seedream-4-0-250828

  • Release date: 2025-08-28 (UTC+8)
  • APIYI price: $0.03 / image (≈ ¥0.21 list)
  • Resolution tiers: 1K / 2K / 4K (broadest coverage)
  • Output format: jpeg
  • Prompt optimization: standard / fast
  • Highlights:
    • Battle-tested stable version
    • Strong visual consistency, balanced 4K detail
    • Only version supporting prompt fast mode — faster generation for cost-sensitive scenarios
  • Known limits:
    • Text rendering weaker than 4.5
    • jpeg output only

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Migration Guidance

1

Assess differences

The three versions are fully compatible at the parameter level — change only the model field to switch. Double-check:
  • Whether your size tier is supported by the new version (5.0 has no 1K / 4K; 4.5 has no 1K; 4.0 has all)
  • Whether you depend on output_format: "png" (5.0 only)
  • Whether you use prompt_optimization: "fast" (4.0 only)
2

Run them side by side

Run the same prompt batch on the old and new versions, compare quality and cost. Validate with a small batch (10-20 images) before scaling.
3

Roll out gradually

Cut traffic in stages (10% / 50% / 100%). At each stage, observe quality, failure rate, and cost before scaling further.
4

Keep a fallback

Keep both old and new model configs in production code. If the new version misbehaves, flip back instantly. All three versions share unified billing — running both has no extra cost.

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Legacy Invocation Example

{/* Switching versions only changes the model field; other params are compatible */}
from openai import OpenAI

client = OpenAI(api_key="sk-your-api-key", base_url="https://api.apiyi.com/v1")

resp = client.images.generate(
    model="seedream-4-0-250828",   # change this line to switch to 4.5 / 5.0
    prompt="A serene mountain landscape at golden hour, snow-capped peaks, ultra detailed, 4K",
    size="4K",                      # NOTE: 5.0 does not support 4K — use 2K or 3K
    response_format="url",
    extra_body={
        "watermark": False,
    }
)

print(resp.data[0].url)

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Cost Comparison

Estimated by typical volume (before top-up bonuses; effective price drops to as low as 80% with bonuses):
VersionUnit Price100 images1,000 images10,000 images
seedream-5-0-260128$0.035$3.5$35$350
seedream-4-5-251128$0.04$4$40$400
seedream-4-0-250828$0.03$3$30$300
How to choose:
  • 4K assets + strong text → 4.5
  • 4K assets + best price → 4.0
  • Best overall / png output / transparent backgrounds → 5.0
  • Long-running stable batch production → 4.0 (proven, cheapest, fast prompt mode)

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Compatibility Matrix

Dimension5.04.54.0Migration note
1K resolution tier❌❌✅Migrating from 4.0 → switch 1K to 2K
4K resolution tier❌✅✅Migrating from 4.5/4.0 → 5.0: switch 4K to 2K or 3K
output_format: "png"✅❌❌Migrating from 5.0 → 4.5/4.0: transparency is lost
prompt_optimization: "fast"❌❌✅Migrating from 4.0: drop the parameter (defaults to standard)
image array (multi-image fusion)✅✅ (up to 10 explicit)✅All three: identical protocol
sequential_image_generation✅✅✅All three: identical protocol
stream streaming✅✅✅All three: identical protocol
Response fields (url / b64_json)identicalidenticalidentical—
Billingper imageper imageper image—