GPT-5.3 Codex
GPT-5.3 Codex is OpenAI's 2026 frontier coding agent, featuring a 400K context window, 77.3% Terminal-Bench score, and superior logic for complex software...
openaiGPT-5February 5, 2026About GPT-5.3 Codex
Learn about GPT-5.3 Codex's capabilities, features, and how it can help you achieve better results.
A New Era of Autonomous Development
GPT-5.3 Codex is OpenAI's most capable agentic coding model, engineered to bridge the gap between static code generation and autonomous software engineering. Built on the next-generation GPT-5 architecture, it integrates specialized professional knowledge with advanced reasoning to handle long-horizon tasks like system administration, deployment monitoring, and architectural refactoring. The model is distinguished by its 'mid-task steering' capability, allowing developers to interact with and guide the agent in real-time as it navigates complex projects.
Recursive Intelligence and Performance
Having been trained using its own earlier iterations to debug and optimize its own deployment, GPT-5.3 Codex represents a significant step toward self-improving AI systems. It excels in Terminal-Bench 2.0 environments, demonstrating an ability to manage live terminals, run unit tests, and iteratively fix bugs without human intervention. This recursive training approach has resulted in highly efficient token usage and a massive 400,000-token context window, capable of digesting entire enterprise repositories in a single pass.
Seamless Professional Integration
Available through a dedicated Codex app, CLI, and IDE extensions, the model is designed for deep integration into modern workflows. It is particularly effective at identifying zero-day exploits, optimizing data pipeline architectures, and performing production-grade audits of legacy codebases. With its superior logic and competitive pricing, it has quickly become the gold standard for high-stakes software engineering tasks.
Use Cases for GPT-5.3 Codex
Discover the different ways you can use GPT-5.3 Codex to achieve great results.
Autonomous Software Engineering
Architecting and building modular, multi-file software projects from high-level specifications.
Production Code Auditing
Analyzing live codebases for concurrency issues, memory leaks, and architectural technical debt.
Real-Time DevOps Automation
Managing terminal-based workflows, including server setup, container deployment, and cluster scaling.
Cybersecurity Vulnerability Remediation
Identifying and fixing zero-day exploits and software vulnerabilities with high-capability defensive logic.
Interactive Prototyping
Generating production-ready landing pages and web apps from hand-drawn wireframes or underspecified prompts.
Data Pipeline Architecture
Tracing and optimizing complex data flows across multiple processing layers and asynchronous environments.
Strengths
Limitations
API Quick Start
openai/gpt-5.3-codex
import OpenAI from 'openai';
const openai = new OpenAI();
async function main() {
const completion = await openai.chat.completions.create({
messages: [{ role: 'user', content: 'Audit this Swift actor for race conditions' }],
model: 'gpt-5.3-codex',
});
console.log(completion.choices[0].message.content);
}
main();Install the SDK and start making API calls in minutes.
What People Are Saying About GPT-5.3 Codex
See what the community thinks about GPT-5.3 Codex
"They actually dropped GPT-5.3 Codex the minute Opus 4.6 dropped LOL"
"Codex is delivering better code at roughly 1/7th the price"
"The performance per price of GPT-5.3 Codex is just absurd"
"I made GPT-5.3-Codex-Spark read its own service site and build a new website. It finished in a blink"
"This model correctly reasoned about Swift actor isolation... the day it shipped"
"Just migrated our entire backend orchestration to Codex agents and the reliability is terrifyingly high"
Videos About GPT-5.3 Codex
Watch tutorials, reviews, and discussions about GPT-5.3 Codex
“GPT-5.3 Codex is our first model that was instrumental in creating itself”
“The efficiency in the increase in what it can do with fewer tokens is really fantastic”
“This spool is actually spinning properly as the nozzle moves right here in the simulation”
“We're seeing a massive leap in how it handles real-world hardware integration”
“The recursive training loop here is a literal game changer for accuracy”
“I have not wanted to go back to GPT 5.2 because they just feel slow”
“It really feels like a big speed boost... they told me it is 25% faster than the previous model”
“The latency on small coding edits is virtually non-existent now”
“Handling large legacy codebases is where the 400K context window really shines”
“This is the first time I've felt an AI truly understands my project's architecture”
“This isn't another code helper. This is an AI that builds your entire project while you watch”
“What used to take me days now takes hours with this thing”
“The ability to just dump a whole documentation set into the prompt is insane”
“You can literally see it correcting its own mistakes in the terminal in real-time”
“For anyone building SaaS, this is going to be your most valuable employee”
Supercharge your workflow with AI Automation
Automatio combines the power of AI agents, web automation, and smart integrations to help you accomplish more in less time.
Pro Tips for GPT-5.3 Codex
Expert tips to help you get the most out of GPT-5.3 Codex and achieve better results.
Enable Real-Time Steering
Activate the follow-up behavior in the Codex settings to guide the model mid-build.
Leverage Plan Mode
Use the 'Plan' command for complex refactors to have the model outline its strategy before editing.
Batch Pull Request Reviews
Use the 400K context window to feed the model entire feature branches for deep integration testing.
Context Compaction
Rely on native context compaction for long-running agentic sessions to maintain project focus.
Testimonials
What Our Users Say
Join thousands of satisfied users who have transformed their workflow
Jonathan Kogan
Co-Founder/CEO, rpatools.io
Automatio is one of the most used for RPA Tools both internally and externally. It saves us countless hours of work and we realized this could do the same for other startups and so we choose Automatio for most of our automation needs.
Mohammed Ibrahim
CEO, qannas.pro
I have used many tools over the past 5 years, Automatio is the Jack of All trades.. !! it could be your scraping bot in the morning and then it becomes your VA by the noon and in the evening it does your automations.. its amazing!
Ben Bressington
CTO, AiChatSolutions
Automatio is fantastic and simple to use to extract data from any website. This allowed me to replace a developer and do tasks myself as they only take a few minutes to setup and forget about it. Automatio is a game changer!
Sarah Chen
Head of Growth, ScaleUp Labs
We've tried dozens of automation tools, but Automatio stands out for its flexibility and ease of use. Our team productivity increased by 40% within the first month of adoption.
David Park
Founder, DataDriven.io
The AI-powered features in Automatio are incredible. It understands context and adapts to changes in websites automatically. No more broken scrapers!
Emily Rodriguez
Marketing Director, GrowthMetrics
Automatio transformed our lead generation process. What used to take our team days now happens automatically in minutes. The ROI is incredible.
Jonathan Kogan
Co-Founder/CEO, rpatools.io
Automatio is one of the most used for RPA Tools both internally and externally. It saves us countless hours of work and we realized this could do the same for other startups and so we choose Automatio for most of our automation needs.
Mohammed Ibrahim
CEO, qannas.pro
I have used many tools over the past 5 years, Automatio is the Jack of All trades.. !! it could be your scraping bot in the morning and then it becomes your VA by the noon and in the evening it does your automations.. its amazing!
Ben Bressington
CTO, AiChatSolutions
Automatio is fantastic and simple to use to extract data from any website. This allowed me to replace a developer and do tasks myself as they only take a few minutes to setup and forget about it. Automatio is a game changer!
Sarah Chen
Head of Growth, ScaleUp Labs
We've tried dozens of automation tools, but Automatio stands out for its flexibility and ease of use. Our team productivity increased by 40% within the first month of adoption.
David Park
Founder, DataDriven.io
The AI-powered features in Automatio are incredible. It understands context and adapts to changes in websites automatically. No more broken scrapers!
Emily Rodriguez
Marketing Director, GrowthMetrics
Automatio transformed our lead generation process. What used to take our team days now happens automatically in minutes. The ROI is incredible.
Related AI Models
Claude Sonnet 4.5
Anthropic
Anthropic's Claude Sonnet 4.5 delivers world-leading coding (77.2% SWE-bench) and a 200K context window, optimized for the next generation of autonomous agents.
Grok-3
xAI
Grok-3 is xAI's flagship reasoning model, featuring deep logic deduction, a 128k context window, and real-time integration with X for live research and coding.
Claude 3.7 Sonnet
Anthropic
Claude 3.7 Sonnet is Anthropic's first hybrid reasoning model, delivering state-of-the-art coding capabilities, a 200k context window, and visible thinking.
GLM-4.7
Zhipu (GLM)
GLM-4.7 by Zhipu AI is a flagship 358B MoE model featuring a 200K context window, elite 73.8% SWE-bench performance, and native Deep Thinking for agentic...
Claude Opus 4.5
Anthropic
Claude Opus 4.5 is Anthropic's most powerful frontier model, delivering record-breaking 80.9% SWE-bench performance and advanced autonomous agency for coding.
Grok-4
xAI
Grok-4 by xAI is a frontier model featuring a 2M token context window, real-time X platform integration, and world-record reasoning capabilities.
Kimi K2.5
Moonshot
Discover Moonshot AI's Kimi K2.5, a 1T-parameter open-source agentic model featuring native multimodal capabilities, a 262K context window, and SOTA reasoning.
GPT-5.1
OpenAI
GPT-5.1 is OpenAI’s advanced reasoning flagship featuring adaptive thinking, native multimodality, and state-of-the-art performance in math and technical...
Frequently Asked Questions About GPT-5.3 Codex
Find answers to common questions about GPT-5.3 Codex