Gemini 3.1 Pro Preview API
Gemini 3.1 Pro Preview is Google's most advanced multimodal LLM, excelling in complex reasoning, long-context tasks, and robust agentic workflows.
Gemini 3.1 Pro Preview API - Background
Overview
Gemini 3.1 Pro Preview is Google LLC's most advanced reasoning AI model, released in February 2026 as part of the Gemini 3 series. The Gemini 3.1 Pro Preview API is designed for complex, real-world tasks that require deep thinking, multi-step reasoning, and robust multimodal understanding. It supports native processing of text, images, video, audio, and PDF inputs, making it a versatile solution for demanding enterprise and developer applications.
Development History
Gemini 3.1 Pro Preview builds on the Gemini 3 Pro foundation, introducing significant improvements in reasoning, reliability, and multimodal capabilities. Released on February 19, 2026, it marks a major leap in Google's AI roadmap, with enhancements targeting agentic workflows, software engineering, and long-context tasks. The development focused on reducing hallucinations, increasing token efficiency, and optimizing for complex, tool-driven scenarios.
Key Innovations
- Massive 1M token context window for input and 65k for output, enabling long-context and large-scale document processing
- Deep multimodal support across text, images, video, audio, and PDFs, with seamless cross-modal reasoning
- Agentic and software engineering workflow optimizations, including reliable multi-step tool orchestration and code execution
Gemini 3.1 Pro Preview API - Technical Specifications
Architecture
Gemini 3.1 Pro Preview is a large-scale, transformer-based multimodal model with native support for text, image, video, audio, and PDF inputs. It features advanced tool integration, function calling, and agentic workflow capabilities, with custom variants optimized for tool use and agentic tasks.
Parameters
Exact parameter count is undisclosed, but the model operates at the frontier scale, competing with leading models such as Claude Opus 4.6 and GPT-5 series.
Capabilities
- Processes and reasons over multimodal inputs including text, images, video, audio, and PDFs
- Supports function calling, structured output, code execution, and batch API operations
- Handles extremely long contexts (up to 1,048,576 input tokens) with high factual consistency and stability
Limitations
- Does not support image or audio generation, live API integration, or maps grounding
- Preview status may result in quality fluctuations in non-agentic scenarios; ultra-long outputs are best generated in steps
Gemini 3.1 Pro Preview API - Performance
Strengths
- Exceptional reasoning and factual accuracy, with significantly reduced hallucinations compared to previous versions
- Superior performance on software engineering, agentic workflows, and long-context multimodal tasks
Real-world Effectiveness
In real-world applications, the Gemini 3.1 Pro Preview API demonstrates robust performance in complex, high-stakes scenarios such as financial modeling, autonomous coding agents, and interactive design. Its high scores on benchmarks like ARC-AGI-2 (77.1%), GPQA Diamond (94.3%), and SWE-Bench Verified (80.6%) reflect its capability to handle abstract reasoning, scientific knowledge, and agentic coding tasks. The model's efficiency and reliability make it a strong choice for enterprise and developer use cases requiring advanced AI reasoning.
Gemini 3.1 Pro Preview API - When to Use
Scenarios
- You have a large-scale document analysis or data synthesis project involving diverse formats such as text, images, and PDFs. The Gemini 3.1 Pro Preview API excels in processing and reasoning over multimodal inputs with a massive context window, enabling comprehensive analysis and extraction of insights from complex datasets. This leads to improved efficiency and accuracy in knowledge management and research workflows.
- You are developing autonomous coding agents or need to automate software engineering workflows. The Gemini 3.1 Pro Preview API is optimized for agentic tasks, offering reliable multi-step tool orchestration and code execution. This results in faster development cycles, reduced manual intervention, and higher code quality for enterprise software projects.
- You require interactive, real-time design or simulation tools that integrate multimodal data and user input. The Gemini 3.1 Pro Preview API supports advanced use cases like 3D simulations with gesture tracking and generative music, making it ideal for creative industries and product prototyping. This enables rapid iteration and richer user experiences.
Best Practices
- Leverage the model's multimodal and long-context capabilities for tasks that require deep reasoning and cross-format understanding.
- For ultra-long outputs or highly complex generations, break tasks into manageable steps to ensure optimal quality and reliability.