Gemini 3.5 Flash is a mid-tier reasoning model that Google announced at its I/O event on May 19, 2026, framing the release as Pro-level reasoning at Flash-class latency. The model is built on the Gemini the listed price Flash reasoning foundation and introduces explicit thinking levels that let developers tune the trade-off between quality, cost, and response speed, with most of Google's published results drawn from the high thinking configuration. This design targets agentic and coding workloads that previously required the Pro tier, aiming to bring stronger step-by-step reasoning into a lower-latency package suitable for production applications.

According to independent third-party analysis, the model is intended to handle complex multi-step tasks such as code generation, function orchestration, and structured tool use, while remaining responsive enough for interactive use. The reasoning foundation carries over the Flash family's characteristic balance of capability and efficiency, and the tiered thinking controls let teams dial up depth for harder prompts or scale back for simpler queries. For practitioners, this makes Gemini 3.5 Flash a practical fit when you need stronger reasoning than a baseline Flash model but want to keep latency and cost closer to Flash than Pro, especially in agent pipelines, code assistants, and workflows that combine retrieval, tool calls, and multi-turn reasoning.