Seedream 5.5 Is Live: 100-Round Editing, Native Transparency

Key Takeaways

New model, live now: seedream-5-5-261028 through the official BytePlus channel, available in the Default and SVIP groups on the same /v1/images/generations endpoint as the rest of the Seedream family
Multi-turn editing is the headline: ByteDance says unedited regions are preserved at the pixel level, so the same image can go through 100 rounds without drifting, blurring, or picking up color casts
Native RGBA output: text-to-image and image-to-image both return PNGs with an alpha channel, including partial transparency, with no background removal needed
Up to 100 layer-decomposition images: one base plus as many as 99 independent layers; regular text layers also return OCR text, per-line positions and approximate styling
Two-part billing: $0.008 per reference image, $0.020 per 1K / 1.5K output, $0.035 per 2K or custom-size output; failed requests are not billed

Background

Seedream is ByteDance’s image-generation family on BytePlus ModelArk. APIYI already served 5.0 Pro, 5.0, 5.0 Flash, 4.5 and 4.0, covering everything from maximum fidelity to high-volume low-cost output. The ByteDance Seed team released Seedream 5.5 on 9 November 2026, and APIYI brought it online on 13 November. This generation does not chase higher resolution. It targets the three pain points that keep image models out of professional production: stability across successive edits, usable transparent assets, and realism with small text. The old problem with multi-turn editing was compounding error. Each edit changed one area, but background, skin tone and material drifted, so by round fifteen the image no longer resembled the original. Seedream 5.5 is trained specifically on preserving unedited regions. In the official demo, one portrait goes through 100 successive edits — clothing, accessories and desktop objects change repeatedly, while small items such as rings and eyeglass frames are still edited precisely, with consistent occlusion and lighting. The other change is transparency. Getting an alpha-channel PNG used to require layer decomposition or manual cutout. Seedream 5.5 generates transparent or semi-transparent backgrounds directly, so generated elements can enter a design pipeline as standalone assets.

Detailed Analysis

Three core upgrades

Multi-turn editing, pixel-level preservation

ByteDance says unedited regions are kept at the pixel level, reducing color shifts, detail loss and image degradation across edits. The same piece supports up to 100 rounds of continuous editing.

Native RGBA assets

Text-to-image and image-to-image both return images with an alpha channel, supporting full and partial transparency. Edges, light transmission and refraction are rendered together, so no background removal is required.

Better realism and text

Lighting, materials and skin texture look closer to real photography, with less overexposure and excessive gloss. Complex glyphs and densely packed small text render noticeably better.

Layer decomposition with OCR

One image becomes a base plus up to 99 layers. With text_recognition enabled, regular text layers return their content, per-line positions and approximate styling.

Official evaluation: six production scenarios improve

ByteDance ran six scenario tests on the MagicArena platform with experienced image evaluators: e-commerce, marketing, film and television, gaming, office productivity, and fashion design. The official conclusion is that Seedream 5.5 beats 5.0 Pro on both quality score and usability rate in all six, with usability in film/TV and office productivity more than doubling over the previous generation. A separate GSB study compared text structure and realism. All four comparisons against the previous version were positive, with image-to-image realism reaching +55.62%. Against leading models such as GPT Image 2.5 Sunburst and Nano Banana 2.1, ByteDance says Seedream 5.5 leads on text structure and has a clear advantage in text-to-image realism. It also reports severe text corruption down to 0.4% and minor corruption at 1.7%.

These figures come from ByteDance Seed’s official launch post (9 November 2026) and are vendor self-reported, not an independent third-party rerun. Our own measurements are in the next section.

APIYI tests: 12–29 seconds, billing matches the official tiers

On launch day (13 November 2026, UTC+8) we ran a set of calls with a test token. The main findings:

Speed: standard text-to-image takes about 12–29 seconds; a 1K layer-decomposition request capped at 3 images returned 2 images in about 13.5 seconds
Size limits: 2240x2064 and 8592x537 both came back at the requested dimensions; stepping past the total-pixel or aspect-ratio limit returns 400
Billing: 1K text-to-image $0.020, 2K text-to-image $0.035; 1K with one reference $0.028, 2K with two references $0.051
Layer decomposition: a 1K request capped at 3 returned 2 images and billed 2 × $0.020 + 1 × $0.008 = $0.048
Not supported: n: 2 is silently ignored and still returns one image; sequential_image_generation returns 400 for any value

Technical specifications

Item	Specification
Model ID	`seedream-5-5-261028`
Endpoint	`POST /v1/images/generations` (generation and editing share it)
Preset tiers	`1K` / `1.5K` / `2K`; omitting `size` is billed at `2K`
Custom size	921,600–4,624,220 total pixels, aspect ratio 1/16–16/1
Reference images	Up to 10, as a URL array or a single URL / data URI
Transparent output	`background: "transparent"` + `output_format: "png"`
Layer decomposition	Exactly one PNG / JPEG input; `max_images` 2–100, default 30
Output format	`png` (default) / `jpeg`; returns `url` or `b64_json`
Not supported	`quality`, `n`, `sequential_image_generation`
Measured latency	About 12–29 seconds; set client timeouts to 60 seconds or more

Practical Use

Recommended scenarios

E-commerce and ad revisions: outfit, background and scene changes on the same model, refined through multi-turn editing instead of regenerating from scratch
Design asset production: transparent PNGs go straight into Figma, Photoshop or video compositing without cutout or edge cleanup
Poster localization: decompose layers, read text content and positions through OCR, then swap copy for each language
Storyboards and game assets: refine one frame repeatedly without degrading quality, which suits long-running projects

Not ideal for: print work that needs 3K / 4K (5.5 tops out around 4.62M pixels; use 4.5), or high-volume work where the lowest unit price matters most (5.0 Flash is $0.018 per request).

Code example

from openai import OpenAI

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

resp = client.images.generate(
    model="seedream-5-5-261028",
    prompt="A perfume hero shot: a transparent glass bottle on a pale stone plinth, side backlight, clean background, 16:9 composition",
    size="2K",
    response_format="url",
    extra_body={
        "watermark": False,          # always disable for commercial work
    },
)
print(resp.data[0].url)              # URL expires in about 24 hours; download it now

For transparent assets, add two parameters to extra_body. Note that jpeg has no alpha channel, so png is required:

extra_body={
    "background": "transparent",
    "output_format": "png",
    "watermark": False,
}

For multi-turn editing, download each output to your own object storage immediately and pass its URL back in the image array for the next round. ByteDance recommends RGB input without an alpha channel and background: "opaque" for multi-turn work.

Best practices

Porting from 5.0 or 4.x? Remove unsupported fields first: sequential_image_generation returns 400 for any value (including "disabled"), n is silently ignored, and this model has no quality parameter.

Pick the tier deliberately: 1K / 1.5K must be passed explicitly; 2K, an omitted size, and a custom WxH all bill at $0.035 per image
Reference images are billed separately: $0.008 each, so count them before multi-image fusion; 5.0 Flash’s free reference images do not carry over
Layer decomposition bills per actual image: max_images is a ceiling, not a promise, and one input-image fee is added; start with 1K
Do not rely on prompts for transparency: asking for a transparent background in text can produce a painted checkerboard; send background: "transparent" with output_format: "png"
Relax timeouts for a synchronous API: there is no task ID, so a dropped connection loses the result while the request is still billed; widen reverse-proxy and serverless limits too
Download URL results immediately: upstream links expire in about 24 hours, so never store them as long-term addresses

Pricing and Availability

Pricing

Item	Price
Reference image	$0.008 / image
Output · 1K / 1.5K	$0.020 / image
Output · 2K / custom size	$0.035 / image
Layer decomposition	Billed per returned image, plus one input-image fee
Failed requests (bad parameters, moderation blocks)	Not billed

Against the rest of the family: a 2K output plus one reference costs about $0.043, roughly 36% of 5.0 Pro ($0.12 per request); ByteDance also says 2K square-image editing costs less than half of 5.0 Pro. 5.0 Flash is cheaper at $0.018 per request but has no native RGBA transparency and no 100-round editing, while 4.5 at $0.04 per image is the option for 4K.

Prices match the provider and may change with the official price list; the table is a reference, and the Model Pricing tab in the top navigation is authoritative: Model Pricing.

Recharge promotions

Model pricing matches BytePlus. Savings come from the recharge bonus program: up to 20% extra credit on a single top-up, roughly 17% off effective cash cost. A 1K output at $0.020 works out to about $0.0167, and a 2K output at $0.035 to about $0.0292. Available groups: Default, SVIP.

Summary and Recommendations

Seedream 5.5 is not about bigger images. It is about making two things genuinely usable: revising the same image over and over, and taking generated output straight into a design pipeline. Pixel-level preservation across 100 rounds, native RGBA output, and up to 100 decomposition images with text OCR all point at professional workflows. For selection: use seedream-5-5-261028 for multi-turn revisions, transparent assets and poster localization; keep 5.0 Flash for high-volume low-cost output; use 4.5 when you need 4K print assets. When integrating, remember four things: choose the size tier explicitly, count reference images as billed input, use background plus png for transparency, and leave 5.0’s sequence parameters behind. ByteDance has confirmed that a Pro version of the 5.5 series will follow, with more complex context and creative instructions. We will cover it when it ships.

Sources: ByteDance Seed launch post (9 November 2026) seed.bytedance.com/en/blog/more-realistic-images-more-stable-editing-across-100-rounds-introducing-seedream-5-5; BytePlus ModelArk Seedream 5.5 documentation docs.byteplus.com/en/docs/ModelArk/seedream-5-5; pricing and measured charges from APIYI calls and the pricing API on 13 November 2026 (UTC+8).

Changelog

AI Radar

Seedream 5.5 Is Live: 100-Round Editing, Native Transparency

Key Takeaways

Background

Detailed Analysis

Three core upgrades

Multi-turn editing, pixel-level preservation

Native RGBA assets

Better realism and text

Layer decomposition with OCR

Official evaluation: six production scenarios improve

APIYI tests: 12–29 seconds, billing matches the official tiers

Technical specifications

Practical Use

Recommended scenarios

Code example

Best practices

Pricing and Availability

Pricing

Recharge promotions

Summary and Recommendations

​Key Takeaways

​Background

​Detailed Analysis

​Three core upgrades

Multi-turn editing, pixel-level preservation

Native RGBA assets

Better realism and text

Layer decomposition with OCR

​Official evaluation: six production scenarios improve

​APIYI tests: 12–29 seconds, billing matches the official tiers

​Technical specifications

​Practical Use

​Recommended scenarios

​Code example

​Best practices

​Pricing and Availability

​Pricing

​Recharge promotions

​Summary and Recommendations

Key Takeaways

Background

Detailed Analysis

Three core upgrades

Official evaluation: six production scenarios improve

APIYI tests: 12–29 seconds, billing matches the official tiers

Technical specifications

Practical Use

Recommended scenarios

Code example

Best practices

Pricing and Availability

Pricing

Recharge promotions

Summary and Recommendations