OpenAIGPT-5.3 Codex: Product update
GPT-5.3 Codex: Product update. First seen 21 Oct 2026 Catalogues list a 400,000 tokens context window. 6 evidence links.
Facts as of
- Context window
- 400,000
- Max output
- 128,000
- Input
- text · image
- Output
- text
Alex's take
Alex has not commented on this signal yet. When Alex posts about a signal, the post appears here and on the home page beside it.
Evidence links 6
- models.dev · cataloguefirst · models.dev
- models.dev · catalogueevidence linkmodels.dev
- models.dev · catalogueevidence linkmodels.dev
- OpenAI · deprecationsevidence linkplatform.openai.com
- OpenAI · pricingevidence linkdevelopers.openai.com
- Arena · leaderboardsevidence linkopenai.com