GPT-5.1 vs Gemini 1.5 Flash

1. Configurable Reasoning for Agentic Tasks

• Built to excel in autonomous or semi-autonomous coding workflows, with adjustable reasoning effort for planning, refactoring and debugging.

2. Fast Multi-Modal Input with Large Output

• Accepts both text and image inputs while producing text outputs.
• Offers up to 128 k output tokens, allowing long responses and code generation across multiple files.

3. Large Context & Knowledge Cut-Off

• 400 k token context window supports processing large codebases or documents.
• Knowledge cut-off of Sep 30 2024 ensures familiarity with recent tools and frameworks.

4. Reasoning Token Support

• Provides explicit support for reasoning tokens, enabling developers to fine-tune the balance between reasoning depth and speed.

1. Extremely fast and cost-efficient

• Designed for ultra-low latency inference.
• Handles high-throughput real-time applications and large-scale pipelines.

2. Strong multimodal capabilities

• Accepts text, images, audio, video, and PDFs.
• Efficient cross-modal understanding suitable for classification, extraction, and captioning.

3. Excellent for long-context tasks

• Supports up to 1M tokens, enabling analysis of long documents, transcripts, and entire codebases.
• Performs well on long-context translation and summarization.

4. Optimized for production workloads

• Low operational cost and fast inference make it ideal for enterprise automation.
• Great for chatbots, customer support systems, and background agent tasks.

5. High throughput with scalable rate limits

• Flash variants support extremely high RPM for high-traffic environments.

6. Reliable performance on everyday tasks

• Good at chat, rewriting, transcription, extraction, and structured reasoning.
• More efficient than Pro for tasks that don't require deep reasoning.

7. Ideal for multimodal high-volume apps

• Strong performance on captioning, OCR-style extraction, audio transcription, and video understanding.

8. Designed for developer workflows

• Supports function calling, structured output, and integration with the Gemini API and Vertex AI.