GPT-5.3 Codex
JSON →The latest Codex iteration, featuring improved context handling and advanced code analysis capabilities.
Specs
context window 272K tokens
max output 128K tokens
input price $1.75 / 1M tokens
output price $14 / 1M tokens
Capabilities
code-generationfunction-callingstreamingjson-modetool-usereasoningvisionprompt-caching
Dates
releasedMar 2026
knowledge cutoffOct 2025
Resources
API
full doc /v1/models/gpt-5.3-codex