Codex 1

Name: Codex 1
Author: OpenAI

Released

2025-05-16

Last refreshed

2026-04-18

Status

Researched 278d ago

DeprecatedProprietaryCommercial use: conditionalCodingAgentsLong context

Codex 1 is a legacy integration reference; keep it only while you identify a current replacement.

OpenAI releases · 44 in the last 12 monthsChangelog →

Specifications

Family: OpenAI Codex
Released: 2025-05-16
Context: 192k
Architecture: Decoder Only
Specialization: code
Openness: Proprietary
License: ProprietaryCommercial use: conditional
Weights: Not released
Code: Unknown
Training: Reinforcement Learning

Created by

OpenAI

Cutting-edge research and development.

San Francisco, California, United States

Founded 2015

Website

Pricing

No tracked provider token pricing is available yet.

Links

Website

About

OpenAI's primary Codex model for software engineering, built on o3 architecture. Trained via reinforcement learning on real-world coding tasks. Features sandboxed container execution, GitHub PR export, diff review, and multi-file reasoning. Default model for the OpenAI Codex cloud coding agent, available on Plus, Pro, Business, and Enterprise tiers.

Provider price ladder

No tracked provider token pricing is available for this model yet.

Capabilities

ReasoningCode Execution

Benchmark peer barsfor Coding

SWE-bench VerifiedRank 57 of 83

Claude Fable 5

96.0

Claude Opus 5

96.0

Claude Mythos Preview

93.9

Claude Opus 4.8

88.6

Codex 1current

72.1

Benchmark scores(1)

Scores are benchmark-specific and are direction-aware: the same numeric gap can mean very different outcomes across suites. Use the leaderboard context and this model's provider route to decide whether the winning margin is meaningful for your workload.