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OpenKey

Gemini 3.5 Flash

GoogleReleased May 19, 2026

Gemini 3.5 Flash is Google's high-efficiency multimodal model, bringing near-Pro level coding and reasoning at Flash-tier cost and speed. It is highly optimized for coding proficiency and parallel agentic execution...

Try in playground
Context window
1.0M tokens
Max output
66K tokens
Input
text, image, video, file, audio
Output
text
Tokenizer
Gemini
Knowledge cutoff
Jan 1, 2025
Released
May 19, 2026
Reasoning
always on

Pricing

Per 1M tokens. The provider price and our flat 3% fee are separate columns — what you pay is their sum.

Per 1M tokensProvider+ 3% feeYou pay
Input$1.50$0.045$1.54
Output$9.00$0.270$9.27
Cache read$0.150$0.0045$0.154
Cache write$0.083$0.0025$0.086

Benchmarks

Artificial Analysis

Intelligence index
50.2
Coding index
70.1
Agentic index
37.4

Design Arena

CategoryEloWin rateRank
agenticgamedevagents121755.1%#3
agentichtmlslidesagents116245.8%#7
agenticslidesagents124457.5%#4
agenticslides(html)agents116245.7%#7
agenticslides(python-pptx)agents124257.8%#3
androidnativeagents126154.9%#5
Full-stackagents126758.1%#6
htmlslidesagents118349%#9
Mobile appsagents126357.2%#2
pptxslidesagents124457.7%#3
python-pptxslidesagents124757.4%#4
Web appsagents126254.2%#5
3Dmodels131060.3%#14
ASCII artmodels131462.4%#5
Codemodels130658.5%#12
Data vizmodels126755.1%#23
Game devmodels133059.4%#8
SVGmodels131163.4%#3
UI componentsmodels131459.7%#11
Websitesmodels129957.6%#14

Head-to-head preference voting. How we filter and rank

Supported parameters

  • include_reasoning
  • max_tokens
  • reasoning
  • response_format
  • seed
  • stop
  • structured_outputs
  • temperature
  • tool_choice
  • tools
  • top_p

Call it

OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model google/gemini-3.5-flash.

Code sample language
curl https://api.openkey.ai/v1/chat/completions \
  -H "Authorization: Bearer $OPENKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3.5-flash",
    "messages": [{"role": "user", "content": "Hello"}]
  }'
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.openkey.ai/v1",
    api_key=os.environ["OPENKEY_API_KEY"],
)

completion = client.chat.completions.create(
    model="google/gemini-3.5-flash",
    messages=[{"role": "user", "content": "Hello"}],
)
print(completion.choices[0].message.content)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.openkey.ai/v1",
  apiKey: process.env.OPENKEY_API_KEY,
});

const completion = await client.chat.completions.create({
  model: "google/gemini-3.5-flash",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does Gemini 3.5 Flash cost via API?
Through OpenKey, Gemini 3.5 Flash costs $1.54 per 1M input tokens and $9.27 per 1M output tokens. That is the provider price ($1.50 / $9.00) plus a flat 3% fee — nothing else.
What is Gemini 3.5 Flash's context window?
Gemini 3.5 Flash accepts up to 1.0M tokens of context and returns up to 66K tokens per request.
Is Gemini 3.5 Flash OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "google/gemini-3.5-flash" using any OpenAI SDK — only the base URL and API key change.
What inputs does Gemini 3.5 Flash support?
Gemini 3.5 Flash accepts text, image, video, file, audio input and produces text output. Its knowledge cutoff is Jan 1, 2025.

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