GitLab Transcend - Intelligent orchestration
Mini toolsGPT 5.3 Codex
By OpenAI
Model family: GPT
GPT-5.3-Codex is a new GPT-5.x family model built for end-to-end software and computer work. It advances coding and debugging, web and app building, and professional tasks like docs, slides and analysis, while setting state-of-the-art results on SWE-Bench Pro, Terminal-Bench, OSWorld and GDPval. About 25% faster than GPT-5.2-Codex, it can be steered interactively during long runs and was itself used as an agent to debug, monitor and deploy its own training pipeline.
Coding
Gen 2
Overview
GPT-5.3-Codex is OpenAI’s most capable agentic coding model, combining GPT-5.2-Codex’s frontier coding with GPT-5.2’s reasoning in one model that is ~25% faster, tops SWE-Bench Pro and Terminal-Bench, and runs long, tool-using workflows on a computer.
About OpenAI
OpenAI is a technology company that specializes in artificial intelligence research and innovation.
Industry:
Artificial Intelligence
Company Size:
4500
Location:
San Francisco, California, US
Website:
openai.com
Benchmark scores
How GPT 5.3 Codex ranks on tracked AI benchmarks. Click any benchmark to see its full leaderboard.
Compare across all benchmarks →Tools using GPT 5.3 Codex
Last updated: April 6, 2026
