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Gemini 2.5 Flash

Gemini 2.5 Flash is Google's first fully hybrid reasoning model, letting developers toggle thinking on or off and set thinking budgets to tune the balance between quality, cost, and latency, all on top of the fast, multimodal foundation of 2.0 Flash.

File InputReasoningTool UseVision (Image)Web SearchImplicit Caching
index.ts
import { streamText } from 'ai'


const result = streamText({
  model: 'google/gemini-2.5-flash',
  prompt: 'Why is the sky blue?'
})
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Frequently Asked Questions

  • What does "hybrid reasoning" mean for Gemini 2.5 Flash?

    It means the model operates in two modes: with thinking disabled (behaving like a fast response model comparable to 2.0 Flash) or with thinking enabled at a configurable budget, where it reasons through the problem before generating an answer.

  • How do thinking budgets work?

    You set a per-request parameter that controls how much deliberation the model applies before responding. A higher budget allows more reasoning steps, improving accuracy on complex tasks at the cost of more tokens and higher latency. A lower budget favors speed and cost.

  • If I disable thinking, how does 2.5 Flash compare to 2.0 Flash?

    2.5 Flash outperforms 2.0 Flash even with thinking disabled. The 2.5 base model is stronger regardless of thinking mode.

  • Does Gemini 2.5 Flash support Google Search tool use?

    Yes. Google Search and code execution are shared capabilities across all Gemini 2.5 models, including Gemini 2.5 Flash.

  • What is the context window for Gemini 2.5 Flash?

    The context window is 1M tokens.

  • How is 2.5 Flash positioned relative to 2.5 Pro?

    Gemini 2.5 Flash sits at the Pareto frontier of cost and performance. It delivers strong reasoning at a lower cost than 2.5 Pro, which targets complex tasks with strong benchmark scores.

  • Is Gemini 2.5 Flash generally available?

    It launched in preview on March 20, 2025. Google later promoted it to stable general availability alongside 2.5 Pro as part of the Gemini 2.5 family expansion.