GPT-5.3 Codex vs Kimi K2-Thinking-0905: Specs & Benchmark Comparison
| Characteristic | GPT-5.3 Codex | Kimi K2-Thinking-0905 |
|---|---|---|
| Company | OpenAI | Moonshot AI |
| Release Date | February 5, 2026 | September 4, 2025 |
| Parameters | — | 1.0T |
| Multimodal | Yes | No |
| Context (input) | 400K | 262K |
| Context (output) | 128K | 66K |
| Input Price / 1M | $1.75 | $0.60 |
| Output Price / 1M | $14.00 | $2.40 |
| Average Score | 0.7 | 0.9 |
Verdict
GPT-5.3 Codex leads in 2 out of 4 comparison categories.
Overall Performance
Both models show comparable average scores: GPT-5.3 Codex — 0.7, Kimi K2-Thinking-0905 — 0.9.
API Cost
Kimi K2-Thinking-0905 is 5.3x cheaper: input $0.60/1M vs $1.75/1M tokens.
Context Window
GPT-5.3 Codex supports a larger context: 400K vs 262K tokens.
Recency
GPT-5.3 Codex is newer: released 2/5/2026 vs 9/4/2025.
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The GPT-5.3 Codex and Kimi K2-Thinking-0905 comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-5.3 Codex or Kimi K2-Thinking-0905 page. See also the complete list of AI model comparisons.