> ## Documentation Index > Fetch the complete documentation index at: https://docs.laozhang.ai/llms.txt > Use this file to discover all available pages before exploring further. # Seedream 5.0 Flash and 5.0 Pro API launch > Seedream 5.0 Flash and 5.0 Pro are live on LaoZhang API with per-call pricing. Get the model IDs, prices, sizes, transparent layers, and migration notes. LaoZhang API now serves Seedream 5.0 Flash at \$0.018 per call and Seedream 5.0 Pro at \$0.12 per call. Both use the existing Seedream endpoint and a `default`-group token, so most integrations switch by changing `model` and removing two unsupported fields. * **Published**: September 25, 2026 * **Last verified**: September 25, 2026 * **Status**: Active. Both models are available in the `default` token group. ## Key facts | Item | Details | | ------------------ | ------------------------------------------------------------------------------------------------- | | Model IDs | `seedream-5-0-flash-260915` (5.0 Flash), `seedream-5-0-pro-260628` (5.0 Pro) | | Price | 5.0 Flash: \$0.018 per call, the same as BytePlus's list price. 5.0 Pro: \$0.12 per call | | Billing | Per-call: one charge for each output image, at any size | | Reference images | Free on Flash. On Pro, the first is free and each additional one costs \$0.003 | | Endpoint | `POST https://api.laozhang.ai/v1/images/generations` with a JSON body, for generation and editing | | Token | `default` group, billing mode Usage first (按量优先, recommended) or Per-call (按次计费) | | Reference images | 1–10 in `image`, as public URLs or `data:` URLs | | `size` levels | 5.0 Flash: `1K`, `1.5K`, `2K`. 5.0 Pro: `1K`, `2K` | | Unsupported fields | `sequential_image_generation` and `stream` return HTTP 400 | | Typical time | 5.0 Flash: under 20 seconds. 5.0 Pro: about 2 minutes | ## Who should care * **High-volume image work**: ad creatives, e-commerce product images, posters, and marketing graphics with text. BytePlus positions 5.0 Flash for faster output, stronger layout and typography, and lower cost at scale. * **Top-quality images**: realistic portraits, fine material detail, professional scenes, and complex instructions. 5.0 Pro has the best image quality and instruction following of the Seedream models, and supports interactive edits, where you describe changes by position in the image. * **Transparent assets**: 5.0 Flash can split an existing image into a background and separate transparent layers. Existing Seedream 5.0, 4.5, and 4.0 integrations aren't affected and keep working without changes. ## What to do Use an API key in the `default` group with the billing mode set to Usage first or Per-call. Confirm that both models appear on the [console pricing page](https://api.laozhang.ai/account/pricing). Set `model` to the 5.0 Flash or 5.0 Pro model ID. Delete `sequential_image_generation`, even when it's `"disabled"`, and `stream` from the request. Pick a `size` the model accepts. Set the client timeout to at least 60 seconds for 5.0 Flash and at least 240 seconds for 5.0 Pro. Run a few of your own prompts on the new model and on your current one, then compare quality, time, and cost in [call logs](https://api.laozhang.ai/log). ## Generate an image with 5.0 Flash This request creates one 2K image without a watermark, then downloads it. Replace the placeholder with your LaoZhang API key; the download step uses `jq`: ```bash theme={null} export LAOZHANG_API_KEY="YOUR_LAOZHANG_API_KEY" curl --fail-with-body --max-time 120 "https://api.laozhang.ai/v1/images/generations" \ -H "Authorization: Bearer $LAOZHANG_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "seedream-5-0-flash-260915", "prompt": "A summer sale poster for iced coffee, headline \"COOL DOWN\" in bold letters, clean layout", "size": "2K", "output_format": "jpeg", "response_format": "url", "watermark": false }' \ -o seedream-flash.json curl -sS -o seedream-flash.jpg "$(jq -r '.data[0].url' seedream-flash.json)" ``` The image URL is in `data[0].url` and stays valid for about 24 hours, so download it promptly. Without `"watermark": false`, the image gets an "AI generated" label. To use 5.0 Pro, change `model` to `seedream-5-0-pro-260628` and raise `--max-time` to at least 240. For edits, Python, and the full parameter list, see the [Seedream API guide](/en/api-capabilities/seedream-image). ## Split an image into transparent layers 5.0 Flash can decompose one reference image into layers. Set `layer_decomposition` to `true` and send exactly one image: ```bash theme={null} curl --fail-with-body --max-time 300 "https://api.laozhang.ai/v1/images/generations" \ -H "Authorization: Bearer $LAOZHANG_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "seedream-5-0-flash-260915", "prompt": "Split this image into separate layers.", "image": "https://ark-doc.tos-ap-southeast-1.bytepluses.com/doc_image/seedream4_imageToimage.png", "layer_decomposition": true, "size": "1K", "output_format": "png", "response_format": "url", "watermark": false }' \ -o seedream-flash-layers.json n=0 jq -r '.data[].url' seedream-flash-layers.json | while read -r url; do n=$((n + 1)) curl -sS -o "layer-$n.png" "$url" done ``` The response lists several images in `data[]`: * `layer-1.png` is the background, with the areas behind removed elements filled in by the model. * Each remaining file is one element as a transparent RGBA PNG. Check the filled-in background before commercial use. Asking for a transparent background in a normal prompt doesn't produce an alpha channel, so use layer decomposition when you need transparency. **Layer decomposition charges \$0.018 for every image it returns.** * The model decides how many layers to return, and the count can differ between runs of the same image. A dozen or so is common, and 16 images cost \$0.288. * Use `size: "1K"` and a client timeout of at least 300 seconds. A 2K request can run for a long time without returning a result and is still charged. * If an image can't be decomposed, the request returns HTTP 400 and isn't charged. You can retry it. ## Migration notes When you move a Seedream 5.0 or 4.x request to 5.0 Flash or 5.0 Pro, check these fields: * **`sequential_image_generation` and `stream`**: remove both. Any value, including `"disabled"`, returns HTTP 400. * **`n`**: ignored. Each request returns one image, except for layer decomposition, so send separate requests when you need several. * **`size` levels**: 5.0 Flash accepts 1K, 1.5K, and 2K, and uses 2K when `size` is omitted. 3K and 4K return HTTP 400. 5.0 Pro accepts 1K and 2K. * **Aspect ratio**: with a `size` level, 5.0 Flash chooses the aspect ratio from the content. For a fixed ratio, pass exact pixels such as `2560x1440`. * **Exact pixels on 5.0 Flash**: 921,600 to 4,624,220 pixels in total, with the long side no more than 16 times the short side. * **Exact pixels on 5.0 Pro**: up to about 4.19 million pixels, for example `2048x2048`, or `2720x1530` for 16:9. * **Reference images**: up to 10. An eleventh returns HTTP 400. * **Output format**: `output_format` accepts `png` or `jpeg`. * **Response format**: `response_format` accepts `url` (valid for about 24 hours) or `b64_json`. ## Compare Seedream versions | Model | Price per call | `size` levels | Best for | | --------- | -------------- | ------------------ | ---------------------------------------------------------- | | 5.0 Flash | \$0.018 | `1K`, `1.5K`, `2K` | Volume, speed, poster layouts, transparent layers | | 5.0 Pro | \$0.12 | `1K`, `2K` | Highest quality, realistic portraits, complex instructions | | 5.0 | \$0.035 | `2K`, `3K` | 3K output, sequential generation, streaming | | 4.5 | \$0.045 | `2K`, `4K` | 4K output | | 4.0 | \$0.035 | `1K`, `2K`, `4K` | 4K output | 5.0 Pro costs about 3.4 times as much as 5.0 and is slower, so use 5.0 or 5.0 Flash for routine work. Prices are LaoZhang API public pricing as of September 25, 2026. ## Frequently asked questions ### How is layer decomposition billed? Per returned image, at \$0.018 each. The model decides how many layers to return, and you can't set the count in advance, so a request that returns 16 images costs \$0.288. A request that fails with HTTP 400 because the image can't be decomposed isn't charged. ### Why does my request return HTTP 400 after switching from Seedream 5.0? Check these causes, most common first: 1. The request still includes `sequential_image_generation` or `stream`. Remove both. 2. `size` is a level the model doesn't accept, such as `3K` or `4K`. 3. The request sends more than 10 reference images. ### Does 5.0 Pro cost more at 2K or with reference images? No. LaoZhang API charges a flat \$0.12 for each output image at any size. The first reference image is free, and each additional one costs \$0.003, so ten references add at most \$0.027. BytePlus's own pricing for 5.0 Pro depends on output resolution and also charges for input reference images. ### Can I get a transparent background by asking for one in the prompt? No. The output has no alpha channel. Use [layer decomposition](#split-an-image-into-transparent-layers) with 5.0 Flash to get transparent PNG layers. ### Do I need to migrate from Seedream 5.0? No. `seedream-5-0-260128` stays available and remains the model for 3K output, sequential generation, and streaming. For 4K, keep using 4.5 or 4.0. ### Am I charged if my client times out? A client timeout isn't the same as a failure, because the server may still finish the image and charge for it. Check [call logs](/en/faq/call-logs) before you resend. Requests that return an error without an image, such as a parameter error, aren't charged. ## Sources and related links ### BytePlus * [BytePlus ModelArk image generation API](https://docs.byteplus.com/en/docs/ModelArk/1541523): request parameters, `size` ranges, and URL lifetime * [BytePlus image generation tutorial](https://docs.byteplus.com/en/docs/ModelArk/1824121): model positioning, speed, and input image limits ### LaoZhang API Model IDs, prices, groups, and billing types come from LaoZhang API's public pricing configuration as of September 25, 2026: * [Model and pricing catalog](/en/models): current prices for every Seedream version * [Console pricing page](https://api.laozhang.ai/account/pricing): the prices that apply to your account * [Token management](https://api.laozhang.ai/token): create an API key and set its group and billing mode * [Call logs](/en/faq/call-logs): check the model and charge for each request ### Related documentation * [Seedream API: generate and edit images](/en/api-capabilities/seedream-image) * [Image generation APIs: models and pricing](/en/api-capabilities/image-generation-guide) * [Latest announcements](/en/changelog)