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GPT-5.3-Codex vs Kimi K2

Kimi K2 leads in 4 of 8 categories

Arena ELO

Kimi K2

Cheaper

Kimi K2

Faster

Kimi K2

Detailed Comparison

CategoryGPT-5.3-CodexKimi K2
ProviderOpenAI Moonshot
Context Window128K 128K
Input Price ($/1M)$1.75 $0.55 WIN
Output Price ($/1M)$14 $2.2 WIN
Arena ELON/A 1380 WIN
CodingN/A 65.8% SWE-bench
ReasoningN/A 60.2% BrowseComp
Speed (tokens/sec)N/A ~50 t/s WIN
Open SourceNo Yes

Frequently Asked Questions

Which is cheaper, GPT-5.3-Codex or Kimi K2?

Kimi K2 is approximately 83% cheaper than GPT-5.3-Codex per million tokens.

Which is better for coding, GPT-5.3-Codex or Kimi K2?

GPT-5.3-Codex scores N/A on coding benchmarks, while Kimi K2 scores 65.8% SWE-bench.

Which has a larger context window?

GPT-5.3-Codex supports 128K context, while Kimi K2 supports 128K.

Is GPT-5.3-Codex or Kimi K2 open source?

GPT-5.3-Codex is proprietary. Kimi K2 is open source.