Discover OpenAI's GPT-5.3-Codex for Coding Excellence

Unlock advanced coding and knowledge tasks with GPT-5.3-Codex.

Input: text · image Output: text Context: 400,000 tokens Release: 2026-02-24

OpenAI's GPT-5.3-Codex, released on February 24, 2026, is a cutting-edge coding model designed for complex software engineering tasks. With a context length of 400,000 tokens, it supports both text and image inputs, generating text outputs. This model excels in multi-language coding, debugging, and deployment, while also performing well in structured knowledge tasks like document drafting and spreadsheet analysis. Enhanced with cybersecurity awareness, it identifies vulnerabilities and is optimized for efficient workflows, making it a valuable tool for professionals in various domains.

Use Cases

Here are a few ways teams apply OpenAI: GPT-5.3-Codex in practice—from fast drafting to multimodal understanding. Adapt these ideas to your workflow.

Streamline complex software development tasks

Draft documents and analyze spreadsheets

Identify vulnerabilities in code

Create presentations and conduct research

Key Features

A quick look at the capabilities that make this model useful in real projects.

Supports text and image inputs

Optimized for long-running workflows

Enhanced cybersecurity awareness

Fast and token-efficient performance

Strong multi-language coding capabilities

Specs

Overview

Vendor
openai

Model ID
openai/gpt-5.3-codex

Release
2026-02-24

Modalities & context

Input
text · image

Output
text

Context
400,000 tokens

Parameters & defaults

Supported parameters: include_reasoning, max_tokens, reasoning, response_format, seed, structured_outputs, tool_choice, tools

Defaults: temperature 0.2, top_p 0.95

Benchmark tests: OpenAI: GPT-5.3-Codex

We ran this model against a few representative prompts to show its range. Review the outputs below and be the judge.

Text

Prompt:

Write 150 words on how AI might positively upend work, leisure and creativity

AI could positively upend work, leisure, and creativity by shifting people from routine effort to higher-value expression. At work, AI can automate repetitive tasks—scheduling, reporting, data cleanup—so people spend more time on strategy, relationships, and problem-solving. It can also act as a “co-pilot,” helping workers learn faster, draft ideas, and make better decisions, which may widen access to skilled jobs. In leisure, AI can remove friction from daily life: smarter assistants can handle planning, translation, and personalized recommendations for travel, books, and learning. That saved time can become true free time—more rest, family connection, and exploration. For creativity, AI lowers technical barriers. Someone with a story idea can generate visuals, music, or prototypes without years of specialized training. Rather than replacing imagination, AI can amplify it—offering prompts, variations, and instant feedback that spark original work. Used thoughtfully, AI could make life not just more efficient, but more human.

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Chat with GPT-5.3-Codex

up.end

/ˌəpˈend/

verb

To “upend” means to completely disrupt, overturn, or drastically change the established order or structure of something. It implies a significant shift or alteration that can potentially have far-reaching consequences. When something is upended, it is turned upside down or transformed in a way that challenges conventional norms or expectations. The term often carries a sense of innovation, transformation, and sometimes even a hint of upheaval, indicating that the changes are not just minor adjustments but rather a fundamental reimagining of the status quo.

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