Gemini 3.5 Flash
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. Effective input at a 70% cache-hit rate:$0.555/M. Implicit caching is on by default for current Gemini models (discounted automatically on cache hits), plus an explicit CachedContent API with storage-based billing for guaranteed savings.
Use Gemini 3.5 Flash in 30 seconds
OpenAI-compatible: swap the base_url, keep your SDK. POST /v1/chat/completions
from openai import OpenAI
client = OpenAI(
base_url="https://synthorai.io/v1",
api_key="sk-syn-...",
)
resp = client.chat.completions.create(
model="gemini-3.5-flash",
messages=[{"role": "user", "content": "Summarize this diff"}],
)
print(resp.choices[0].message.content)import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://synthorai.io/v1",
apiKey: "sk-syn-...",
});
const resp = await client.chat.completions.create({
model: "gemini-3.5-flash",
messages: [{ role: "user", content: "Summarize this diff" }],
});
console.log(resp.choices[0].message.content);curl https://synthorai.io/v1/chat/completions \
-H "Authorization: Bearer sk-syn-..." \
-H "Content-Type: application/json" \
-d '{
"model": "gemini-3.5-flash",
"messages": [{"role": "user", "content": "Hello"}]
}'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.Chat.Completions.New(context.TODO(), openai.ChatCompletionNewParams{
Model: "gemini-3.5-flash",
Messages: []openai.ChatCompletionMessageParamUnion{
openai.UserMessage("Summarize this diff"),
},
})
fmt.Println(resp.Choices[0].Message.Content)
}import com.openai.client.OpenAIClient;
import com.openai.client.okhttp.OpenAIOkHttpClient;
import com.openai.models.chat.completions.*;
OpenAIClient client = OpenAIOkHttpClient.builder()
.baseUrl("https://synthorai.io/v1")
.apiKey("sk-syn-...")
.build();
ChatCompletion resp = client.chat().completions().create(
ChatCompletionCreateParams.builder()
.model("gemini-3.5-flash")
.addUserMessage("Summarize this diff")
.build());
System.out.println(resp.choices().get(0).message().content().orElse(""));About Gemini 3.5 Flash
Gemini 3.5 Flash is the model Google's catalog labels its most intelligent for sustained frontier performance on agentic and coding tasks, and the model page calls it particularly effective for rapid agentic loops involving complex coding cycles and iterations.
- It supports thinking, takes text, image, video, audio, and PDF input across a 1,048,576-token context window with 65,536 output tokens, and offers function calling, structured outputs, code execution, computer use (preview), grounding, and caching.
- Synthorai provides access through its OpenAI-compatible chat endpoint.
Specs & limits
| Max output (vendor spec) | 65,536 |
| Modalities | text + image + video + audio → text |
| Features | tools · structured_output · streaming · vision · batch · caching · reasoning · computer_use |
| Notable | 1,048,576-token input / 65,536 output; code execution supported; computer use in Preview. |
| Prompt caching | automatic + explicit · min 1,024-token prefix |
FAQ
Is the Gemini 3.5 Flash API free to try?
Yes: new accounts get 10 trial calls and up to $1 in free credit, no card required. At $1.5/M input tokens, that credit alone covers roughly 83 requests of ~8K tokens against Gemini 3.5 Flash.
What is Gemini 3.5 Flash best at?
Sustained frontier performance on agentic tasks, plus effective for rapid agentic coding loops and computer use preview and grounding support. See the About section for the full picture from the vendor's own release notes.
How much does Gemini 3.5 Flash cost?
Gemini 3.5 Flash costs $1.5 per million input tokens and $9 per million output tokens on Synthorai. That is the provider's list price, with no platform markup. Cached input tokens bill at $0.15/M.
Does Gemini 3.5 Flash support prompt caching?
Yes: automatic caching is on by default, with an explicit mode for guaranteed savings. Cached input tokens bill at $0.15/M vs $1.5/M uncached; prompts need a 1,024-token stable prefix to cache. Prompt caching guide →
How do I get access to Gemini 3.5 Flash?
Point your existing OpenAI SDK at base_url="https://synthorai.io/v1", set model="gemini-3.5-flash", and you're done. One API key covers every model on the gateway.
What is Gemini 3.5 Flash's knowledge cutoff?
Gemini 3.5 Flash's knowledge cutoff is 2025-01, per the vendor's official documentation (as of 2026-07-09).