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Get started freeGPT-5.1 Codex vs Gemini 3 Pro
Compare GPT-5.1 Codex and Gemini 3 Pro. Build AI products powered by either model on Appaca.
Model Comparison
| Feature | GPT-5.1 Codex | Gemini 3 Pro |
|---|---|---|
| Provider | OpenAI | |
| Model Type | text | text |
| Context Window | 400,000 tokens | 1,000,000 tokens |
| Input Cost | $1.25/ 1M tokens | $4.00/ 1M tokens |
| Output Cost | $10.00/ 1M tokens | $18.00/ 1M tokens |
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Build your first app freeStrengths & Best Use Cases
GPT-5.1 Codex
OpenAI1. Purpose-Built for Agentic Coding
- Designed specifically for environments where the model acts as an autonomous or semi-autonomous coding agent.
- Optimized for multi-step reasoning in code tasks such as planning, refactoring, debugging, file generation, and tool coordination.
2. Enhanced Coding Intelligence
- Extends GPT-5.1's advanced reasoning capabilities to handle complex software architecture decisions.
- Better accuracy in code generation across languages (JavaScript, Python, TypeScript, Go, Rust, etc.).
- Produces cleaner, more idiomatic code aligned with modern frameworks and best practices.
3. Superior Tool Use & Code Navigation
- Excels at reading, understanding, and transforming multi-file codebases.
- Works well with Codex workflows that simulate real developer tooling.
- Strong at following function signatures, constraints, and code patterns within an existing project.
4. Long-Range Context Awareness
- 400,000-token context window enables the model to ingest large repositories or multiple files simultaneously.
- Supports deep analysis of project structures, dependencies, and cross-file logic.
5. Multi-Modal Development Capabilities
- Accepts text + image input and output - suitable for tasks like:
- Reading UI mockups or screenshots to generate code
- Understanding architectural diagrams
- Reviewing images of whiteboard sessions
6. Agentic Workflow Optimization
- Built to manage longer chains of thought and execution typically required in:
- Automated code repair
- Project bootstrapping
- Linting and migration tasks
- Long-running coding agents using planning + execution loops
7. Continually Updated Model Snapshot
- Codex-specific version receives regular upgrades behind the scenes.
- Ensures the latest coding improvements without requiring developers to update model names.
8. Reliable Instruction Following
- Highly consistent in honoring explicit constraints:
- Code styles
- Folder structures
- API contracts
- Framework conventions
9. Broad API Support
- Works across Chat Completions, Responses API, Realtime, Assistants, and more.
- Ideal for apps that need live, reasoning-heavy coding agents or generative dev environments.
Gemini 3 Pro
Google1. State-of-the-art reasoning
- Top performance across academic reasoning, scientific knowledge, math, and complex problem-solving.
- Excels at long-horizon, multi-step workflows and deep logical interpretation.
2. World-leading multimodal capabilities
- Natively understands text, images, videos, audio, and code.
- Ranked highest on benchmarks like MMMU-Pro, Video-MMMU, ScreenSpot-Pro.
3. Exceptional coding + agentic workflows
- Strong in competitive coding and real-world agentic tasks (SWE-Bench Verified, Terminal-Bench, LiveCodeBench).
- Improved tool calling, planning, and execution for autonomous or semi-autonomous agents.
4. Powerful for long-context tasks
- Effective at 128K-1M context windows with high retrieval accuracy.
- Ideal for document-heavy workflows, research, analysis, multi-file coding, and multi-document reasoning.
5. Strong information synthesis and interpretation
- Outperforms peers in chart reasoning, OCR, structured extraction, and screen understanding.
- Excellent at combining multimodal inputs into coherent, concise answers.
6. High reliability for enterprise tasks
- Benchmarks show superior factuality, grounding, and parametric knowledge.
- Strong multilingual accuracy and global commonsense performance.
7. Optimized for production agents
- Designed for complex multi-step planning, simultaneous task execution, and improved consistency.
- Works across coding, research, creative workflows, UI generation, and data-heavy applications.
Prompts to Get Started
Use these prompts to power AI products you build on Appaca. Each works great with the models above.
Best for GPT-5.1 Codex
textSystem Design Document
Write a system design document for a new service or feature.
Workload Audit
Audit your current workload to identify what to drop, delegate, or defer.
Developer Onboarding Guide
Write an onboarding guide to help new developers get productive quickly.
Best for Gemini 3 Pro
textIndemnification Clause Explainer
Explain indemnification clauses in contracts in plain language.
Customer Feedback Survey
Design a customer satisfaction survey that yields actionable insights.
Listicle Writing
Write an engaging listicle article with actionable numbered points.