Seedream 4.0
Provider list prices: no platform markup, pay-as-you-go. These are official list prices. Logged-in customers may see effective prices including workspace discounts on /console/pricing.
Use Seedream 4.0 in 30 seconds
OpenAI-compatible: swap the base_url, keep your SDK. POST /v1/images/generations
from openai import OpenAI
client = OpenAI(
base_url="https://synthorai.io/v1",
api_key="sk-syn-...",
)
resp = client.images.generate(
model="seedream-4-0-250828",
prompt="a watercolor lighthouse at dawn",
size="1024x1024",
)
print(resp.data[0].b64_json[:80])import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://synthorai.io/v1",
apiKey: "sk-syn-...",
});
const resp = await client.images.generate({
model: "seedream-4-0-250828",
prompt: "a watercolor lighthouse at dawn",
size: "1024x1024",
});
console.log(resp.data?.[0]?.b64_json?.slice(0, 80));curl https://synthorai.io/v1/images/generations \
-H "Authorization: Bearer sk-syn-..." \
-H "Content-Type: application/json" \
-d '{
"model": "seedream-4-0-250828",
"prompt": "a watercolor lighthouse at dawn",
"size": "1024x1024"
}'package main
import (
"context"
"fmt"
"github.com/openai/openai-go/v3"
"github.com/openai/openai-go/v3/option"
)
func main() {
client := openai.NewClient(
option.WithBaseURL("https://synthorai.io/v1"),
option.WithAPIKey("sk-syn-..."),
)
resp, _ := client.Images.Generate(context.TODO(), openai.ImageGenerateParams{
Model: "seedream-4-0-250828",
Prompt: "a watercolor lighthouse at dawn",
Size: "1024x1024",
})
fmt.Println(resp.Data[0].B64JSON[:80])
}import com.openai.client.OpenAIClient;
import com.openai.client.okhttp.OpenAIOkHttpClient;
import com.openai.models.images.*;
OpenAIClient client = OpenAIOkHttpClient.builder()
.baseUrl("https://synthorai.io/v1")
.apiKey("sk-syn-...")
.build();
ImagesResponse resp = client.images().generate(
ImageGenerateParams.builder()
.model("seedream-4-0-250828")
.prompt("a watercolor lighthouse at dawn")
.size("1024x1024")
.build());
System.out.println(resp.data().orElseThrow().get(0).b64Json().orElseThrow().substring(0, 80));About Seedream 4.0
Seedream 4.0 is ByteDance's SOTA-level multimodal image creation model on BytePlus ModelArk, which the official page says breaks the creative boundaries of traditional text-to-image models by natively supporting text, single-image, and multi-image inputs.
- In one model it covers multi-image fusion with subject consistency, image editing, and group image generation, outputting JPEG images from 1K up to 4K with as many as 14 reference images.
- Streaming generation and a faster prompt-optimization mode are available.
- Synthorai schedules it behind the OpenAI-compatible images interface.
Specs & limits
| Modalities | text + image → image |
| Features | vision |
| Image capabilities | 1K-4K output (up to 4096x4096), jpeg; unified text-to-image + single/multi-reference image editing; batch generation with reference + generated images <=15; $0.03/image, 500 IPM |
| Notable | Officially announced on the ByteDance Seed blog 2025-09-09; version date 250828 encoded in the model id. |
FAQ
Is the Seedream 4.0 API free to try?
Yes: new accounts get 10 trial calls and up to $1 in free credit, no card required. That's enough to try Seedream 4.0 against your real workload before adding a payment method.
What is Seedream 4.0 best at?
Native text, single-image, and multi-image inputs, plus multi-image fusion with subject consistency and 1K to 4K output, 14 reference images. See the About section for the full picture from the vendor's own release notes.
How much does Seedream 4.0 cost?
Seedream 4.0 costs $0.03 per generated image on Synthorai: pay-as-you-go, no platform markup, no subscription.
How do I generate images with the Seedream 4.0 API?
POST to /v1/images/generations on Synthorai with model="seedream-4-0-250828". It follows the OpenAI images API shape, so no vendor SDK is needed.
How do I get access to Seedream 4.0?
Point your existing OpenAI SDK at base_url="https://synthorai.io/v1", set model="seedream-4-0-250828", and you're done. One API key covers every model on the gateway.