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GPT-5.3-Codex vs GPT-5.5

GPT-5.3-Codex leads in 2 of 8 categories

Arena ELO

Tie

Cheaper

GPT-5.3-Codex

Faster

Tie

Detailed Comparison

CategoryGPT-5.3-CodexGPT-5.5
ProviderOpenAI OpenAI
Context Window128K 128K
Input Price ($/1M)$1.75 WINN/A
Output Price ($/1M)$14 WINN/A
Arena ELON/A N/A
CodingN/A N/A
ReasoningN/A N/A
Speed (tokens/sec)N/A N/A
Open SourceNo No

Frequently Asked Questions

Which has a larger context window?

GPT-5.3-Codex supports 128K context, while GPT-5.5 supports 128K.

Is GPT-5.3-Codex or GPT-5.5 open source?

GPT-5.3-Codex is proprietary. GPT-5.5 is proprietary.

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