Gemini 3.5 Flash

The Gemini 3.5 Flash API delivers a massive 1M token context window with native multimodal reasoning. Built for speed, this Gemini 3.5 model excels at video analysis, high-speed document QA, and low-latency agentic workflows at a fraction of the cost.

Modalities

Context

API Usage Examples

curl --request POST "https://gptproto.com/v1/chat/completions" \
  --header "Authorization: Bearer $GPTPROTO_API_KEY" \
  --header "Content-Type: application/json" \
  --data '{
    "model": "gemini-3.5-flash",
    "messages": [
      {
        "role": "user",
        "content": "Hello"
      }
    ]
  }'

Gemini 3.5 Flash pricing

Estimate a request with real work scenarios. GPTProto token pricing is 40% below official rates.

Cost calculator

Multi-turn agent with cached context.

Input tokens$0.9 / 1M$0.00135

Output tokens$5.4 / 1M$0.00432

Cache write tokens$0.09 / 1M$0.00027

Cache read tokens$0.09 / 1M$0.00225

Cost per request$0.00819

Top up

GPTProto vs official pricing.

Requests

You pay

40% off

$100

You receive$100.00

Save$66.67 (40%)vs Google official

Key Gemini 3.5 Flash API Capabilities

The Gemini 3.5 Flash API is built for scale, speed, and intelligence. Leverage native multimodal processing and huge context for your next AI project.

1M Token Context Window

Analyze massive datasets with near-perfect recall. Perfect for large document sets and complex codebases that require a broad view.

Native Multimodal Reasoning

Seamlessly process text, images, audio, and video. Native integration prevents data loss found in traditional separate encoders.

High-Throughput Performance

Optimized for speed with 40-50% faster TTFT than Pro models. Ideal for real-time applications and high-frequency API calls.

Context Caching Savings

Drastically reduce costs for repetitive queries. Cache long prompts to save up to 90% on input costs for frequent datasets.

Related Models

All Models

Model					Input → Output
Gemini 3.5 FlashCurrent		1.05M	$0.90 / $5.40 per 1M	$0.09 / $0.09 per 1M	Input: TextInput: ImageInput: Document Output: Text
Gemini 3.7 Flash		1.05M	$0.45 / $2.25 per 1M	— / $0.04 per 1M	Input: TextInput: ImageInput: Document Output: Text
Grok 4.6		500K	$1.20 / $3.60 per 1M	— / $0.30 per 1M	Input: TextInput: Image Output: Text
Qwen3.8 Max		1M	$1.80 / $5.40 per 1M	$2.25 / $0.23 per 1M	Input: TextInput: ImageInput: VideoInput: Document Output: Text
Claude Opus 5		1M	$4.00 / $20.00 per 1M	$5.00 / $0.40 per 1M	Input: TextInput: ImageInput: Document Output: Text
Gemini 3.6 Flash		1.05M	$0.45 / $2.25 per 1M	— / $0.04 per 1M	Input: TextInput: ImageInput: Document Output: Text
Gemini 3.5 Flash Lite		1.05M	$0.18 / $1.50 per 1M	$0.02 / $0.02 per 1M	Input: TextInput: ImageInput: Document Output: Text
Kimi K3		1.05M	$2.70 / $13.50 per 1M	$0.27 / $0.27 per 1M	Input: TextInput: ImageInput: Document Output: Text
GPT 5.6 Luna		1.05M	$0.16 / $0.96 per 1M	$0.20 / $0.02 per 1M	Input: TextInput: ImageInput: Document Output: Text
GPT 5.6 Terra		1.05M	$1.60 / $9.60 per 1M	$2.00 / $0.16 per 1M	Input: TextInput: ImageInput: Document Output: Text
GPT 5.6 Sol		1.05M	$4.00 / $24.00 per 1M	$5.00 / $0.40 per 1M	Input: TextInput: ImageInput: Document Output: Text
Grok 4.5		500K	$1.20 / $3.60 per 1M	$0.30 / $0.30 per 1M	Input: TextInput: Image Output: Text
Claude Sonnet 5		1M	$1.60 / $8.00 per 1M	$2.00 / $0.16 per 1M	Input: TextInput: Document Output: Text
Minimax M3		1.05M	$0.48 / $0.96 per 1M	$0.10 / $0.10 per 1M	Input: TextInput: ImageInput: Document Output: Text
GLM 5.2		1.05M	$1.26 / $3.96 per 1M	$0.23 / $0.23 per 1M	Input: TextInput: ImageInput: Document Output: Text
Claude Fable 5		1M	$8.00 / $40.00 per 1M	$10.00 / $0.80 per 1M	Input: TextInput: Document Output: Text
Qwen3.7 Max		1M	$0.36 / $1.44 per 1M	$0.07 / $0.07 per 1M	Input: TextInput: Document Output: Text
DeepSeek v4 Flash	—	1.05M	$0.44 / $1.32 per 1M	— / $0.01 per 1M	Input: Text Output: Text
DeepSeek v4 Pro	—	1.05M	$1.32 / $3.96 per 1M	— / $0.04 per 1M	Input: Text Output: Text
Grok 4.3		1M	$0.75 / $1.50 per 1M	$0.12 / $0.12 per 1M	Input: TextInput: Image Output: Text
Kimi K2.6		262K	$0.85 / $3.60 per 1M	$0.14 / $0.14 per 1M	Input: TextInput: Document Output: Text
GLM 5.1		205K	$1.26 / $3.96 per 1M	$0.23 / $0.23 per 1M	Input: TextInput: Document Output: Text
GLM 5 Turbo		203K	$1.08 / $3.60 per 1M	$0.22 / $0.22 per 1M	Input: TextInput: Document Output: Text
Gemini 3.1 Flash Lite Preview		1.05M	$0.15 / $0.90 per 1M	$0.01 / $0.01 per 1M	Input: TextInput: ImageInput: Document Output: Text
DeepSeek v3.2		164K	$0.17 / $0.25 per 1M	$0.02 / $0.02 per 1M	Input: Text Output: Text
Minimax M2.5		205K	$0.24 / $0.96 per 1M	$0.30 / $0.02 per 1M	Input: TextInput: Document Output: Text
Gemini 3.1 Pro Preview		1.05M	$1.20 / $7.20 per 1M	$0.12 / $0.12 per 1M	Input: TextInput: ImageInput: Document Output: Text
Kimi K2.5		262K	$0.54 / $2.70 per 1M	$0.09 / $0.09 per 1M	Input: TextInput: Document Output: Text
Qwen Turbo		—	$0.04 / $0.18 per 1M	$0.009 / $0.009 per 1M	Input: Text Output: Text
Gemini 3 Flash Preview		1.05M	$0.30 / $1.80 per 1M	$0.03 / $0.03 per 1M	Input: TextInput: Image Output: Text
Doubao Seed 1.6 Thinking 250715		262K	$0.10 / $0.97 per 1M	—	Input: TextInput: Image Output: Text
Doubao Seed 1.6 Thinking 250615		262K	$0.10 / $0.97 per 1M	—	Input: TextInput: Image Output: Text
Doubao Seed 1.6 Flash 250615		262K	$0.02 / $0.18 per 1M	—	Input: TextInput: Image Output: Text

Common Questions About Gemini 3.5 Flash API

Find technical details and usage tips for the Gemini 3.5 Flash API. We cover performance, cost-efficiency, and integration workflows for developers.

How does the Gemini 3.5 Flash API handle long context?

This Gemini 3.5 model uses a 1M token window with 99% recall. It processes massive datasets, like 10+ PDFs or entire codebases, without losing information. The Flash API architecture is specifically optimized to keep this process fast and cost-effective for developers using the API in production.

Can I use the Gemini 3.5 Flash API for video analysis?

Yes, it is natively multimodal. Unlike models that only see images, the Gemini 3.5 Flash API can reason across up to one hour of video frames natively. This makes it ideal for summarizing meetings or security footage without the need for manual frame sampling or complex pre-processing pipelines.

Is the Gemini 3.5 Flash API faster than Gemini 1.5 Pro?

Absolutely. This Gemini 3.5 variant is optimized for flash inference. It delivers a Time To First Token that is approximately 40-50% faster than the 1.5 Pro version. It is designed for high-throughput scenarios where low latency is critical for user experience, such as real-time customer support bots.

What are the costs for the Gemini 3.5 Flash API?

Pricing is very competitive: $0.075 per 1M input tokens for prompts under 128k. For larger contexts, a small surcharge applies. However, the Gemini 3.5 Flash API supports context caching, which can reduce repetitive query costs by up to 90%, making it one of the most economical high-context models available.

Does the Gemini 3.5 Flash API support JSON mode?

Yes, the API supports structured outputs via a specific response type. By setting the response format to JSON, developers can ensure the Gemini 3.5 output adheres to strict schemas. This is perfect for data extraction, entity recognition, and building reliable agentic workflows that require precise formatting.

How do I migrate my code to use Gemini 3.5 Flash?

Migration is seamless. Our API provides an OpenAI-compatible endpoint. You simply update your base URL and model name to point to Gemini 3.5 Flash. Most system prompts and function definitions from other providers are 1:1 compatible, allowing you to switch to this high-speed Gemini API in minutes.