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Sourced model profile · Current through July 14, 2026

GPT-5.3 Codex

A closed-weight OpenAI API model in the Codex line, documented for language modeling and generation.

Developed byOpenAI
Released
February 5, 2026

What the evidence says

These facts come from the reviewed Epoch AI catalog artifact and its linked primary record. They describe the model. They do not rank it.

Developer [1]
OpenAI
Released [1]
February 5, 2026
Domains [1]
Language
Tasks [1]
Language modeling/generation
Access [1]
API access
Weights [1]
Closed

Where it may fit

These are evidence-bounded screening suggestions, not performance claims or purchase recommendations.

Hosted language generation on OpenAI's API

Consider it for applications that generate language through OpenAI's hosted API where managed access fits the deployment.

Evidence fields: tasks, access [1]

Codex-line evaluation

Consider it when evaluating OpenAI's Codex-branded releases; the name identifies the line, and the record documents language generation.

Evidence fields: name, tasks [1]

Limitations

The source record lists only language modeling and generation. It does not document coding tasks, benchmark results, price, context window, latency, or safety evaluations, and no exact-match Arena rating exists for this record.

Current standing

According to the LMArena snapshot published July 12, 2026, no exact match for this catalog record appears in the style-controlled text category, so this page reports no current rating for GPT-5.3 Codex.