# Seedream 5.5

> ByteDance's newest image model, released November 9, 2026: keep editing the same image for 100 rounds without the untouched areas drifting, generate transparent PNGs directly, and get photos and small text that look closer to real.

- Model page: https://yir.ai/models/seedream-5-5
- Model ID: `bytedance/seedream-5.5`
- Billing: by the channel that ran the job; attempts the upstream did not bill are free.

## What Seedream 5.5 adds over Seedream 5.0 Pro

### Stable across 100 rounds of edits

Untouched areas stay pixel-identical with no color drift, so you can keep refining one image

### Transparent PNGs, no cut-out step

Full and partial transparency straight from a prompt or a reference image, no background removal; not in Yir's API yet

### Closer to a real photo

More natural light and skin with less gloss; image-to-image realism 55.62% ahead of 5.0 Pro in ByteDance's ratings

### Dense small text stays readable

Severe text errors down to 0.4% in ByteDance's tests, even in dense Chinese captions

## Pricing

Current public prices by channel for the same output specification; official prices are a reference. You are billed by the channel that actually runs the job, which may change on failover.

| Output specification | Channel | Public price |
|---|---|---|
| 1K | APIMart | $0.013 ~ $0.0182 / image |
| 1K | KIE | $0.018 ~ $0.0252 / image |
| 2K | APIMart | $0.0228 ~ $0.028 / image |
| 2K | KIE | $0.0315 ~ $0.0387 / image |

## Parameters

- Operation: `generate_image`

| Parameter | Values | Default |
|---|---|---|
| `input` | text / image | text |
| `resolution` | 1K / 2K | 1K |
| `aspect_ratio` | 1:1 / 4:3 / 3:4 / 16:9 / 9:16 / 3:2 / 2:3 / 2:1 / 1:2 / 21:9 | 1:1 |

## Integration

Pick either: the official SDK for new code, or swap the Base URL in projects already using the OpenAI protocol.

### Official SDK (TypeScript)

The SDK calls the Standard API (https://gateway.yir.ai) to submit, wait for and collect jobs; a Go SDK is also available. https://yir.ai/docs/integrations/sdk

```bash
pnpm add @yir-ai/sdk
```

```ts
import { createNodeYirClient } from "@yir-ai/sdk/server";

// Reads YIR_API_KEY from the environment by default: process.env.YIR_API_KEY
const client = createNodeYirClient();

// 1. Submit an image generation job
const job = await client.submitImage({
  model: "bytedance/seedream-5.5",
  input: {
    type: "text",
    prompt: "Create a citrus sparkling water product poster: a clear glass bottle and fresh oranges, cream background, soft natural light, and a crisp product label",
  },
  parameters: {
    resolution: "1K",
    aspect_ratio: "1:1",
    n: 1,
  },
});

// 2. Wait for the job to finish and deliver its result
const result = await client.waitForJob(job.id);
console.log("Delivered files:", result.result);
if (result.result && "files" in result.result) {
  for (const file of result.result.files) {
    console.log("->", file.url);
  }
}
```

### OpenAI-compatible API

OpenAI Images and Sora Videos protocols for OpenAI SDKs and gateways such as new-api; no chat. https://yir.ai/docs/integrations/openai-compatibility

- OpenAI SDK base_url: `https://gateway.yir.ai/openai/v1`
- new-api channel Base URL (channel type OpenAI): `https://gateway.yir.ai/openai`
- Model ID: `bytedance/seedream-5.5`

```bash
curl https://gateway.yir.ai/openai/v1/images/generations \
  -H "Authorization: Bearer $YIR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "bytedance/seedream-5.5",
    "prompt": "Create a citrus sparkling water product poster: a clear glass bottle and fresh oranges, cream background, soft natural light, and a crisp product label",
    "resolution": "1K",
    "aspect_ratio": "1:1"
  }'
```

## FAQ

### Seedream 5.5 or Seedream 5.0 Pro: which should I use?

Pick Seedream 5.5 when you need many rounds of edits on one image or dense small text: in ByteDance's tests it scored higher than 5.0 Pro in all six production use cases, and in film and office work it was usable more than twice as often. Seedream 5.0 Pro can fail over between three providers, while 5.5 runs through one provider for now. ByteDance says a Seedream 5.5 Pro will follow.

### When was Seedream 5.5 released?

ByteDance's Seed team released Seedream 5.5 on November 9, 2026. It is rolling out in Dreamina, CapCut, Doubao and Volcano Engine Ark, and BytePlus ModelArk is ByteDance's API for it outside China. ByteDance says a Pro version of the Seedream 5.5 series will follow.

### How does Seedream 5.5 compare with GPT Image 2.5 and Nano Banana 2.1?

In ByteDance's expert side-by-side ratings, Seedream 5.5 leads GPT Image 2.5 Sunburst and Nano Banana 2.1 on text structure in both text-to-image and image-to-image, and is clearly ahead on text-to-image realism. These are ByteDance's own evaluations on its MagicArena platform, not independent tests.

### Can I call the Seedream 5.5 API on Yir now?

Yes. Text-to-image and edits with up to 10 reference images are live at 1K and 2K, with the price shown before you submit. Transparent output and layer splitting are not in Yir's API yet.

### What does Seedream 5.5 support?

Text-to-image and edits with up to 10 reference images. On Yir: 1K and 2K, ten aspect ratios from 21:9 to 1:2, one image per request. The model also offers 1.5K, transparent output and splitting an image into layers, which Yir does not expose yet. BytePlus has not published its API limits yet.

## Rules

- Authenticate with Authorization: Bearer $YIR_API_KEY; keep the key in a server environment variable, never in browser code, source control, prompts or logs.
- Jobs are asynchronous: keep the Job ID, wait for a terminal state, then read the result; handle failure and cancellation.
- For safe retries, reuse the same idempotency key and request; do not blindly resubmit when the result is unknown.
- Result URLs are temporary; copy files elsewhere if you need to keep them.

## Links

- [Quickstart](https://yir.ai/docs/getting-started/quickstart)
- [API reference](https://yir.ai/docs/reference)
- [llms.txt](https://yir.ai/llms.txt)