Seedream 4.5
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 4.5 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-4-5-251128",
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-4-5-251128",
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-4-5-251128",
"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-4-5-251128",
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-4-5-251128")
.prompt("a watercolor lighthouse at dawn")
.size("1024x1024")
.build());
System.out.println(resp.data().orElseThrow().get(0).b64Json().orElseThrow().substring(0, 80));About Seedream 4.5
Seedream 4.5 is ByteDance's image generation model on BytePlus ModelArk, released as an upgrade to Seedream 4.0.
- The official release notes cite significant improvements in editing consistency, such as preserving subject details and lighting or color tones, plus portrait enhancement and small-text generation.
- It supports text-to-image, single and multi-reference image-to-image with up to 14 reference images, batch image generation, streaming output, and 2K or 4K results, focusing on high-quality standard-mode generation.
- Synthorai makes it available through the OpenAI-compatible image generation endpoint.
Specs & limits
| Modalities | text + image → image |
| Features | vision |
| Image capabilities | 2K/4K output, jpeg; text-to-image, single and multi-reference image-to-image, batch generation; improved text rendering and multi-image consistency; 500 max IPM |
| Notable | Released December 2025 (version date 251128 encoded in the model id); no dedicated docs model page (console-only detail). |
FAQ
Is the Seedream 4.5 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 4.5 against your real workload before adding a payment method.
What is Seedream 4.5 best at?
Editing consistency preserving details and lighting, plus portrait enhancement and small-text generation and up to 14 reference images, 2K or 4K. See the About section for the full picture from the vendor's own release notes.
How much does Seedream 4.5 cost?
Seedream 4.5 costs $0.04 per generated image on Synthorai: pay-as-you-go, no platform markup, no subscription.
How do I generate images with the Seedream 4.5 API?
POST to /v1/images/generations on Synthorai with model="seedream-4-5-251128". It follows the OpenAI images API shape, so no vendor SDK is needed.
How do I get access to Seedream 4.5?
Point your existing OpenAI SDK at base_url="https://synthorai.io/v1", set model="seedream-4-5-251128", and you're done. One API key covers every model on the gateway.