ByA Decisive Leap for Developers
We present today a detailed analysis of GPT-5.3-Codex, introduced by OpenAI—an agentic coding model that is not only 25% faster but also achieves record-breaking scores on prestigious benchmarks such as SWE-bench Pro, Terminal-Bench 2.0, and OSWorld-Verified. This launch elevates the standards of speed, quality, and collaboration in modern software development.
What is GPT-5.3-Codex and why is it Special?
GPT-5.3-Codex is the most advanced model in OpenAI’s Codex series, designed with a developer-first approach. This model completes complex coding tasks with fewer tokens, improved reasoning, and faster inference. As a result, development cycles are accelerated, and production-grade output becomes more reliable.
Record-Breaking Benchmark Performance
SWE-bench Pro (Public)
We observe that GPT-5.3-Codex achieved a score of 56.8%—surpassing previous versions GPT-5.2-Codex (56.4%) and GPT-5.2 (55.6%). This score demonstrates the model’s robustness and maturity in real-world software engineering challenges.
Terminal-Bench 2.0
A score of 77.3% in terminal-based tasks proves that this model is highly capable in CLI workflows, scripting, and system-level automation—where previous models were limited to 64.0% and 62.2%.
OSWorld-Verified (Agentic Computer-Use)
A score of 64.7% in agentic computer use represents a significant leap. This model handles task planning, tool use, and multi-step actions more effectively—making it more reliable in real-world projects. 25% Faster Performance: Revolutionary Improvements in the Inference Stack
We emphasize that GPT-5.3-Codex uses fewer tokens while delivering equal or better quality. Thanks to inference stack improvements, this model runs 25% faster, providing developers with a low-latency, high-throughput experience. This speed is crucial for large codebases, CI/CD pipelines, and real-time collaboration.
Real-Time Collaboration with Developers
Steer & Interact: Control Without Losing Context
In our experience, the biggest advantage of GPT-5.3-Codex is its interactive collaboration capabilities. Developers can guide the model in real-time during their work—asking questions, changing approaches, and precisely directing the solution is now easier than ever.
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Progress Updates in the Codex App
The model provides frequent progress updates within the Codex App, giving teams transparency. This accelerates discussions, decision-making, and iterative improvements—without any loss of context.
Self-Improvement in Training and Deployment
We also observed that early versions of GPT-5.3-Codex were so capable that they were used in the training improvements and deployment of subsequent versions. This self-improving training loop is indicative of the model’s continuous quality enhancement.
From Agentic Coding to General Collaborator
According to OpenAI, what started as an effort to create the best coding agent has now become the foundation for a general-purpose collaborator on the computer. This means Codex no longer just writes code—it extends to building, automation, and creative-technical collaboration.
Access and Availability
We confirm that GPT-5.3-Codex is now available to all paid ChatGPT plan users. It can be accessed through the Codex App, CLI, IDE Extension, and Web. In addition, API availability has also been announced—ensuring scalability for enterprises and startups.
Co-design and Serving on NVIDIA GB200 NVL72
This model has been co-designed, trained, and served on NVIDIA GB200 NVL72 systems. The direct benefits include high-performance computing, improved thermal efficiency, and consistent scaling—essential for large-scale agentic workloads.
Impact on Development Workflows
Faster Delivery, Fewer Errors
The combination of 25% faster speed and improved benchmarks accelerates feature delivery and reduces rework.
High-Quality Code
Greater accuracy with fewer tokens means cleaner code, better test coverage, and improved maintainability.
Team-Level Collaboration
Real-time interaction leads to clearer code reviews, design discussions, and a significant increase in productivity.
Why GPT-5.3-Codex is Future-Ready
We believe that its record-setting performance, faster inference, agentic capabilities, and developer-centric design make it a standard-setter for years to come. This model is ideal for teams that demand scale, speed, and quality—all at once.
Conclusion
We conclude that GPT-5.3-Codex is not just an upgrade, but a new era of coding collaboration. Its benchmark-leading performance, 25% faster speed, and deep collaborative features make it indispensable for modern development. Teams that adopt it today will gain a clear competitive advantage tomorrow.
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Frequently Asked Questions (FAQ)
What is GPT-5.3-Codex?
GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, designed specifically for developers. It offers faster execution, improved reasoning, and record-breaking performance on industry-standard coding benchmarks.
How is GPT-5.3-Codex different from GPT-5.2-Codex?
GPT-5.3-Codex is approximately 25% faster, uses fewer tokens, and delivers higher accuracy across benchmarks such as SWE-bench Pro, Terminal-Bench 2.0, and OSWorld-Verified compared to GPT-5.2-Codex.
What benchmarks does GPT-5.3-Codex excel at?
GPT-5.3-Codex achieved:
56.8% on SWE-bench Pro
77.3% on Terminal-Bench 2.0
64.7% on OSWorld-Verified
These are the highest scores recorded in OpenAI’s Codex series to date.
Who should use GPT-5.3-Codex?
GPT-5.3-Codex is ideal for:
Software developers
DevOps engineers
AI engineers
Startups and enterprises
Teams working on large or complex codebases
Is GPT-5.3-Codex faster than previous models?
Yes. OpenAI states that GPT-5.3-Codex runs 25% faster due to major inference-stack optimizations, making it suitable for real-time and large-scale development workflows.
Does GPT-5.3-Codex support real-time collaboration?
Yes. Developers can interact with and guide the model in real time without losing context. The Codex app also provides frequent progress updates during task execution.
Where can GPT-5.3-Codex be accessed?
GPT-5.3-Codex is available through:
Code App
Command Line Interface (CLI)
IDE Extensions
Web Interface
It will also be accessible via API soon.
Is GPT-5.3-Codex available for free users?
No. GPT-5.3-Codex is currently available only to ChatGPT paid plan users.
What hardware is GPT-5.3-Codex built on?
GPT-5.3-Codex was co-designed, trained, and deployed on NVIDIA GB200 NVL72 systems, ensuring high performance, scalability, and reliability.
Can GPT-5.3-Codex be used for tasks beyond coding?
Yes. While optimized for coding, GPT-5.3-Codex is evolving into a general computer collaborator, capable of handling complex workflows, automation, and multi-step tasks.
Why is GPT-5.3-Codex important for the future of software development?
Because it combines speed, accuracy, agentic intelligence, and collaboration, GPT-5.3-Codex sets a new standard for AI-assisted development and significantly boosts developer productivity.
