GPT-5.3 Codex
GPT-5.3 CodexAlternatives?
CheaperGPT-6.1 Solmax+9%-17%$0.72Remove unsupported parameters+5
OpenMuse Spark Openxhigh+3%-58%$0.84Reasoning off leaves output unchanged · Self-hosted / llama.cpp+1
CheaperGemini 3.8 Flashhigh+9%-69%*$1.24Sampling parameters are ignored+1CheaperGemini 3.6 Flashhigh+6%-69%*$1.60CheaperGPT-6 Solmax+6%-17%$1.04GPT-6.1 Solmax+9%-17%$0.72Remove unsupported parameters+5Gemini 3.8 Flashhigh+9%-69%*$1.24Sampling parameters are ignored+1Gemini 3.6 Flashhigh+6%-69%*$1.60GPT-6 Solmax+6%-17%$1.04
Qwen3.8 Max (0902)thinking+5%-38%$5.41GPT-6.1 Sollow+6%-17%$0.13Remove unsupported parameters+5GPT-5.6 Sollow+3%+66%$0.26
DeepSeek V4.1 Flash 1017maxOpen+3%-89%$0.26Pass back reasoning_content · Chat Completions+4GPT-6 Solhigh+4%-17%$0.37
Claude Opus 5.5low+8%+66%$0.55No forced tool use+5Muse Spark OpenxhighOpen+3%-58%$0.84Reasoning off leaves output unchanged · Self-hosted / llama.cpp+1DeepSeek V4.1 Flash 1017maxOpen+3%-89%$0.26Pass back reasoning_content · Chat Completions+4
Kimi K3maxOpen+3%+25%$2.00Sampling parameters are fixed+3Qwen3.8 FlashthinkingOpen+2%-95%$0.37Context: 400K → 262K+6Kimi K2.6thinkingOpensame-64%$0.80Context: 400K → 256KGPT-6 Astraxhigh+10%—$2.31Monitoring can return HTTP 403+2GPT-6.1 Solxhigh+8%—$0.39Remove unsupported parameters+5GPT-5.6 Solxhigh+5%—$1.18GPT-6 Solxhigh+5%—$0.52GPT-5.5xhigh+2%—$2.63Prompts with >272K input tokensGPT-6 Lunaxhigh+2%—$0.042Function calling only with none · Chat Completions+3GPT-5.6 Terraxhighsame—$0.63Prompts with >272K input tokensGPT-5.6 Lunaxhighsame—$0.085All OpenAI models →History
4 versionsBenchmarks
in Vision & DocumentsWatch out 1
Deprecated›
The official model page marks this model deprecated; plan a migration. Source ↗
FAQ
How much does GPT-5.3 Codex cost?›
$1.75 per 1M input tokens and $14 per 1M output tokens; cached input $0.17 per 1M.
Is GPT-5.3 Codex free to use?›
There is no free API; the cheapest paid price is $1.75 per 1M input tokens.
How good is GPT-5.3 Codex, and what is it best at?›
#34 of 334 in Chat & Knowledge, #9 of 239 in Coding, #60 of 242 in Agents & Tool Use, #25 of 245 in Writing & Language, #31 of 124 in Vision & Documents. Strongest at: Tool calling, Reasoning, Science, Long context, Knowledge, Instructions, Vision.
Is GPT-5.3 Codex better than GPT-5.6 Luna?›
On MMMU-Pro (vision), GPT-5.3 Codex scores 78.5 vs 78.6 — about the same.
How can I use GPT-5.3 Codex?›
Through the API of Azure, OpenAI.
What is the context window of GPT-5.3 Codex?›
400K tokens, with up to 128K output tokens.
When was GPT-5.3 Codex released? Is there a newer version?›
Released 2026-02-05. It has been superseded by GPT-6 Sol.
Is GPT-5.3 Codex open source?›
No, GPT-5.3 Codex is a closed model available through an API. The closest open-weights option here is Muse Spark Open.
Can GPT-5.3 Codex read images?›
It accepts text and images, PDF files as input.
What is GPT-5.3 Codex?›
GPT-5.3 Codex is a closed language model from OpenAI, released Feb 2026.
What are the best alternatives to GPT-5.3 Codex?›
GPT-6.1 Sol (cheaper), Muse Spark Open (open weights).