
Gemini 2.5 Pro and Gemini 3 Pro API Integration Guide
Google's Gemini models offer exceptional multimodal capabilities, advanced reasoning, and competitive pricing. This guide covers how to integrate Gemini 2.5 Pro, Gemini 2.5 Flash, and the latest Gemini 3 Pro through Crazyrouter's API.
Supported Gemini Models#
| Model | Input ($/1M) | Output ($/1M) | Best For |
|---|---|---|---|
| gemini-3-pro-preview | $1.25 | $7.50 | Latest generation |
| gemini-3-pro-preview-thinking | $1.25 | $7.50 | Extended reasoning |
| gemini-3-pro-image-preview | $1.25 | $7.50 | Image generation |
| gemini-3-flash-preview | $0.15 | $0.60 | Fast responses |
| gemini-2.5-pro | $1.25 | $10.00 | Long documents |
| gemini-2.5-pro-thinking | $1.25 | $10.00 | Complex reasoning |
| gemini-2.5-flash | $0.30 | $2.50 | Production workloads |
| gemini-2.5-flash-lite | $0.10 | $0.40 | Cost-effective |
| gemini-2.5-flash-image | $0.30 | $2.50 | Image generation |
Quick Start with OpenAI-Compatible API#
The easiest way to use Gemini models is through the OpenAI-compatible endpoint:
from openai import OpenAI
client = OpenAI(
api_key="sk-your-api-key",
base_url="https://crazyrouter.com/v1",
default_headers={
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36"
}
)
response = client.chat.completions.create(
model="gemini-2.5-pro",
messages=[
{"role": "user", "content": "Explain the theory of relativity in simple terms."}
]
)
print(response.choices[0].message.content)
Native Gemini API Format#
For advanced features, use the native Gemini API format:
Text Generation#
curl -X POST "https://crazyrouter.com/v1beta/models/gemini-2.5-pro:generateContent" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer sk-your-api-key" \
-H "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36" \
-d '{
"contents": [{
"parts": [{"text": "Write a poem about artificial intelligence."}]
}]
}'
Streaming Text Generation#
curl -X POST "https://crazyrouter.com/v1beta/models/gemini-3-pro-preview:streamGenerateContent" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer sk-your-api-key" \
-H "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36" \
-d '{
"contents": [{
"parts": [{"text": "Explain quantum computing step by step."}]
}]
}'
Extended Thinking with Gemini#
Gemini models support extended thinking for complex reasoning:
# Gemini 2.5 Pro with thinking
response = client.chat.completions.create(
model="gemini-2.5-pro-thinking",
messages=[
{"role": "user", "content": "Solve this complex math problem step by step: Find all prime numbers p such that p^2 + 2 is also prime."}
]
)
# Gemini 3 Pro with thinking
response = client.chat.completions.create(
model="gemini-3-pro-preview-thinking",
messages=[
{"role": "user", "content": "Analyze this algorithm's time complexity."}
]
)
Image Generation with Gemini#
Gemini 2.5 Flash Image#
curl -X POST "https://crazyrouter.com/v1beta/models/gemini-2.5-flash-image:generateContent" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer sk-your-api-key" \
-H "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36" \
-d '{
"contents": [{
"parts": [{"text": "Generate an image of a futuristic city at sunset"}]
}],
"generationConfig": {
"responseModalities": ["image", "text"]
}
}'
Gemini 3 Pro Image (with aspect ratio control)#
curl -X POST "https://crazyrouter.com/v1beta/models/gemini-3-pro-image-preview:generateContent" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer sk-your-api-key" \
-H "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36" \
-d '{
"contents": [{
"parts": [{"text": "A serene Japanese garden with cherry blossoms"}]
}],
"generationConfig": {
"responseModalities": ["image"],
"aspectRatio": "16:9"
}
}'
Google Search Integration#
Gemini models can access real-time information via Google Search:
curl -X POST "https://crazyrouter.com/v1beta/models/gemini-2.5-flash:generateContent" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer sk-your-api-key" \
-H "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36" \
-d '{
"contents": [{
"parts": [{"text": "What are the latest developments in AI as of today?"}]
}],
"tools": [{
"googleSearch": {}
}]
}'
Flash Lite Models (Cost-Effective)#
For high-volume, cost-sensitive applications:
# Standard Flash Lite
response = client.chat.completions.create(
model="gemini-2.5-flash-lite",
messages=[{"role": "user", "content": "Summarize this text briefly."}]
)
# Flash Lite with thinking
response = client.chat.completions.create(
model="gemini-2.5-flash-lite-thinking",
messages=[{"role": "user", "content": "Solve this logic puzzle."}]
)
Python SDK Example#
from openai import OpenAI
client = OpenAI(
api_key="sk-your-api-key",
base_url="https://crazyrouter.com/v1",
default_headers={
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36"
}
)
# Gemini 3 Pro for complex reasoning
response = client.chat.completions.create(
model="gemini-3-pro-preview",
messages=[
{"role": "system", "content": "You are a helpful AI assistant with expertise in science."},
{"role": "user", "content": "Explain CRISPR gene editing and its potential applications."}
],
temperature=0.7,
max_tokens=2000
)
print(response.choices[0].message.content)
Pricing Comparison#
| Model | Input ($/1M) | Output ($/1M) |
|---|---|---|
| gemini-3-pro-preview | $1.25 | $7.50 |
| gemini-2.5-pro | $1.25 | $10.00 |
| gemini-2.5-flash | $0.30 | $2.50 |
| gemini-2.5-flash-lite | $0.10 | $0.40 |
| gemini-flash-latest | $0.30 | $2.50 |
Pricing Disclaimer: The prices shown in this article are for demonstration purposes only and may change at any time. Actual billing will be based on the real-time prices displayed when you make your request.
Best Practices#
- Use Flash for production: Gemini 2.5 Flash offers excellent performance at lower cost
- Enable thinking for complex tasks: Use thinking-enabled models for math and reasoning
- Leverage multimodal capabilities: Gemini excels at image and video understanding
- Use streaming for long responses: Better user experience with real-time output
Model Selection Guide#
| Use Case | Recommended Model |
|---|---|
| General chat | gemini-2.5-flash |
| Complex reasoning | gemini-2.5-pro-thinking or gemini-3-pro-preview-thinking |
| Image generation | gemini-2.5-flash-image or gemini-3-pro-image-preview |
| Cost-sensitive | gemini-2.5-flash-lite |
| Latest features | gemini-3-pro-preview |
Getting Started#
- Sign up at Crazyrouter
- Create an API key in the console
- Choose between OpenAI-compatible or native Gemini format
- Start building with Gemini models
For questions, contact support@crazyrouter.com


