Gpt 5 2 Codex Vs Gemini 3 Pro Vs Openai Codex Comparison

Bonisiwe Shabane

-Jan 2, 2026, 3:51 AM

gpt 5 2 codex vs gemini 3 pro vs openai codex comparison

For a few weeks now, the tech community has been amazed by all these new AI models coming out every few days. 🥴 But the catch is, there are so many of them right now that we devs aren't really sure which AI model to use when it comes to working with code, especially as your daily... Just a few weeks ago, Anthropic released Opus 4.5, Google released Gemini 3, and OpenAI released GPT-5.2 (Codex), all of which claim at some point to be the "so-called" best for coding. But now the question arises: how much better or worse is each of them when compared to real-world scenarios? If you want a quick take, here is how the three models performed in these tests:

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Get a detailed comparison of AI language models OpenAI's GPT-5 Codex and Google's Gemini 3 Pro, including model features, token pricing, API costs, performance benchmarks, and real-world capabilities to help you choose the right... GPT-5 Codex is OpenAI’s GPT-5 variant optimized for agentic software engineering inside Codex. It excels at building full projects, refactoring large codebases, debugging, and code review. It supports images/screenshots for frontend work and runs in the Codex CLI, IDE extension, and cloud. Available in Codex surfaces and the OpenAI API (Responses API). Gemini 3 Pro is Google's most intelligent model, designed to help bring any idea to life through state-of-the-art reasoning and multimodal understanding.

It excels as the world's best model for multimodal tasks and stands as Google's most powerful agentic and coding model, delivering richer visualizations and deeper interactivity. The model significantly outperforms Gemini 2.5 Pro across all major benchmarks, achieving breakthrough scores on reasoning tasks like Humanity's Last Exam and GPQA Diamond, setting new standards in mathematics with MathArena Apex, and demonstrating... Gemini 3 Pro is 2 months newer than GPT-5 Codex. It has more recent training data (January 2025 vs September 30, 2024). Gemini 3 Pro has a larger context window (1M vs 400K tokens). Unlike GPT-5 Codex, Gemini 3 Pro supports voice, video processing.

Compare costs for input and output tokens between GPT-5 Codex and Gemini 3 Pro. This software hasn't been reviewed yet. Be the first to provide a review: This software hasn't been reviewed yet. Be the first to provide a review: Posted on Dec 16 • Originally published at tensorlake.ai

Gemini 3 Pro has strong multimodal capabilities but produces simpler, less structured coding outputs. GPT-5.2 delivers more reliable reasoning and polished, production-ready code with minimal cleanup needed. By the end of 2025, two major AI releases had reshaped how developers build and ship software: OpenAI’s GPT-5.2 and Google’s Gemini 3 Pro. Both bring improvements in reasoning, coding assistance, and multimodal capabilities, but they take different approaches to solving developer problems. Gemini 3 Pro was officially launched on November 18, 2025, as Google’s most advanced multimodal model yet, designed to handle complex text, image, audio, and video tasks alongside code and reasoning. Long-Term Memory: Episodic: Stores specific past events or "episodes" of interactions (e.g., "The user mentioned they preferred Python over Java last week").

Semantic: A repository of general facts, world knowledge, and entity relationships (e.g., "Paris is the capital of France"). Procedural: Contains the skills and "how-to" logic for performing tasks, often encoded as system prompts, scripts, or specific tool-calling protocols. Three flagship AI coding models launched within weeks of each other. Claude Opus 4.5 on November 24. Gemini 3.0 Pro on November 18. GPT 5.1 Codex-Max on November 19.

All three claim to be the best model for complex coding tasks and agentic workflows. The benchmarks show they're neck-and-neck. I wanted to see what that means for actual development work. So I gave all three the same prompts for two complex problems in my observability platform: statistical anomaly detection and distributed alert deduplication: same codebase, exact requirements, same IDE setup. Here. I compared all these models on some projects I was working on in my spare time.

I've used the Tool router, which is beta, in the first test, which also helps in dogfood the product. Do check out if you're someone who wants to use tools with your agents but doesn't want to be bothered with context pollution. Read more on the tool router here. SWE-bench Verified: Opus 4.5 leads at 80.9%, followed by GPT 5.1 Codex-Max at 77.9% and Gemini 3 Pro at 76.2% Terminal-Bench 2.0: Gemini 3 Pro tops at 54.2%, demonstrating exceptional tool use capabilities OpenAI has officially released GPT-5.2 on December 11, 2025, marking a significant upgrade in the GPT-5 series.

This point release positions it as the company’s most capable model yet for professional knowledge work, with major advancements in reasoning, long-context processing, tool use, coding, and hallucination reduction. The launch came quickly amid fierce competition, particularly following Google’s Gemini 3 release in November 2025, which had claimed top spots on several leaderboards. GPT-5.2 isn’t a brand-new generation (GPT-5 launched in August 2025, followed by GPT-5.1 in November), but a refined iteration available in three variants: A specialized GPT-5.2-Codex variant focuses on advanced coding and cybersecurity, released alongside for paid users in Codex tools. Both models launched close together and dominate current benchmarks, often trading wins depending on the task: Category GPT-5.2 Strengths Gemini 3 Pro Strengths Edge (Based on Benchmarks & Reports) Reasoning & Math/Science Leads on... Bottom Line: Choose GPT-5.2 for intensive professional work (coding, data analysis, reliable agents)—it’s engineered for productivity and trustworthiness.

Opt for Gemini 3 Pro (via gemini.google.com or Vertex AI) for creative multimodal tasks, video processing, or deep Google ecosystem ties. Comparing 2 AI models · 5 benchmarks · OpenAI, Google GPT-5 Codex (high) offers the best value at $1.25/1M, making it ideal for high-volume applications and cost-conscious projects. Gemini 3 Pro Preview (high) leads in reasoning capabilities with a 90.8% GPQA score, excelling at complex analytical tasks and problem-solving. Gemini 3 Pro Preview (high) achieves a 62.3 coding index, making it the top choice for software development and code generation tasks. All models support context windows of ∞+ tokens, suitable for processing lengthy documents and maintaining extended conversations.

Detailed comparison of capabilities, features, and performance. View detailed specifications and capabilities View detailed specifications and capabilities Access both GPT-5 Codex and Gemini 3 Pro in a single workspace without managing multiple API keys.

Gpt 5 2 Codex Vs Gemini 3 Pro Vs Openai Codex Comparison

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