GPT-5 Codex vs Kimi K3 (Comparative Analysis)
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Comparative Analysis: GPT-5 Codex vs. Kimi K3
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Overview
GPT-5 Codex was released 9 months before Kimi K3.
 GPT-5 Codex |  Kimi K3 | |
|---|---|---|
Model Provider The organization behind this AI's development | OpenAI | MoonshotAI |
Input Context Window Maximum input tokens this model can process at once | 400K tokens | 1M tokens |
Output Token Limit Maximum output tokens this model can generate at once | 128K tokens | Not specified tokens |
Release Date When this model first became publicly available | September 23, 2025 10 months ago September 23rd, 2025 | July 16, 2026 11 days ago July 16th, 2026 |
Knowledge Cutoff Latest training-data date reported by the provider | September 30, 2024 | Not reported |
Capabilities & Features
Compare supported features, modalities, and advanced capabilities
GPT-5 Codex | Kimi K3 | |
|---|---|---|
Input Types Supported input formats | 📝Text🖼️Image | 📝Text🖼️Image |
Reasoning Controls Defaults and configurable reasoning effort | Always enabled | Enabled by defaultEffort: Max, High, LowDefault: Max |
Output Types Supported output formats | 📝Text | 📝Text |
Tokenizer Text encoding system | GPT | Other |
Key Features Advanced capabilities | ✓Function Calling✓Structured Output✓Reasoning Mode✓Content Moderation | ✓Function Calling✓Structured Output✓Reasoning ModeContent Moderation |
Pricing
GPT-5 Codex is roughly 0.4x less expensive compared to Kimi K3 for input tokens and roughly 0.7x less expensive for output tokens.
| GPT-5 Codex | Kimi K3 | |
|---|---|---|
Input Token Cost Cost per million input tokens | $1.25 per million tokens | $3.00 per million tokens |
Output Token Cost Cost per million output tokens | $10.00 per million tokens | $15.00 per million tokens |
Web Search Cost Additional cost for each web search operation | $0.01 per search | Not specified |
Cache Read Cost Cost to reuse cached input tokens | $0.13 per million tokens | $0.30 per million tokens |
Benchmarks
Compare relevant benchmarks between GPT-5 Codex and Kimi K3.
| GPT-5 Codex | Kimi K3 | |
|---|---|---|
Intelligence Index Overall model quality across independent evaluations | Benchmark not available. | 57.1 (Artificial Analysis index; higher is better) |
Coding Index Programming performance across independent evaluations | Benchmark not available. | 76.2 (Artificial Analysis index; higher is better) |
Agentic Index Ability to complete multi-step agentic tasks | Benchmark not available. | 50.1 (Artificial Analysis index; higher is better) |
Best Design Arena Score Highest human-preference Elo score across design arenas | 1,138 Elo (#26 in Webapps (52.4% win rate)) | 1,456 Elo (#1 in 3D (69.2% win rate)) |
At a Glance
Quick overview of what makes GPT-5 Codex and Kimi K3 unique.
GPT-5 Codex by OpenAI understands both text and images, can use external tools and APIs, offers advanced reasoning, generates structured data. It can handle standard conversations with its 400K token context window. Reasonably priced at $1.25/M input and $10.00/M output tokens. Includes built-in content moderation for safer outputs. Released September 23rd, 2025.Kimi K3 by MoonshotAI understands both text and images, can use external tools and APIs, offers advanced reasoning, generates structured data. It can handle standard conversations with its 1M token context window. Premium pricing at $3.00/M input and $15.00/M output tokens. Released July 16th, 2026.Explore More Comparisons
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