Gemini 2.5 Flash
Google Gemini 2.5 Generally Available May 2025
Google's fast and affordable model with 1M token context and optional thinking. Best price-to-performance in the Gemini 2.5 family for high-volume tasks.
Context
1M
tokens
Input
$0.30
per MTok
Output
$2.50
per MTok
About
Gemini 2.5 Flash is Google's state-of-the-art workhorse model, specifically designed for advanced reasoning, coding, mathematics, and scientific tasks. It includes built-in "thinking" capabilities, enabling it to provide responses with greater...
Modalities
Input
Text Vision Audio Video Documents / PDFs Code
Output
Text Code
Code Examples
curl https://openrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer $OPENROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "gemini-2.5-flash",
"messages": [
{ "role": "user", "content": "Explain quantum entanglement in one sentence." }
]
}' API Parameters
| Name | Type | Description |
|---|---|---|
include_reasoning | boolean | Include the model's internal reasoning trace in the response. |
max_tokens deprecated | integer | Deprecated. Use max_completion_tokens. |
reasoning | object | Configuration for extended-thinking / reasoning mode. |
response_format | one of | Constrain output to a JSON schema or an enum (structured outputs). |
seed | integer | Deterministic seed for sampling. Same seed + same prompt produces identical output. |
stop | array | Up to 4 sequences where the API will stop generating tokens. |
structured_outputs | boolean | Enable JSON-schema-constrained output. |
temperature | number | Sampling temperature; higher values produce more random output. 0 is deterministic. |
tool_choice | one of | Controls which (if any) tool is called: "none", "auto", "required", or a specific tool. |
tools | array | List of tools (functions) the model may call. |
top_p | number | Nucleus sampling: consider only tokens whose cumulative probability ≥ top_p. |
Standard OpenAI-compatible parameters. Consult the provider docs for model-specific behaviour.
Benchmark Scores
| Benchmark | Score |
|---|---|
| MMLU | 88.4% |
| GPQA Diamond | 82.8% |
| MATH | 88% |
Performance
180
tok / sec
output speed
Source: Google AI docs + Artificial Analysis, April 2026
Strengths & Limitations
Best For
Very low cost at scale
1M token context window
Optional thinking mode
Free tier available
Multimodal inputs
Limitations
Lower ceiling than Gemini 2.5 Pro on hard reasoning
Thinking mode adds latency and cost
Tags
FastCheapLong ContextThinkingVision