GPT-5.3-Codex vs R1 0528
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for GPT-5.3-Codex and R1 0528.
GPT-5.3-Codex
GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results...
R1 0528
May 28th update to the [original DeepSeek R1](/deepseek/deepseek-r1) Performance on par with [OpenAI o1](/openai/o1), but open-sourced and with fully open reasoning tokens. It's 671B parameters in size, with 37B active...
Technical Specifications
| Specification | GPT-5.3-Codex | R1 0528 |
|---|---|---|
| Provider | OpenAI | DeepSeek |
| Context Window | 400,000 tokens | 163,840 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | self hostable |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2026-02-24 | 2025-05-28 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5.3-Codex
$1.75
R1 0528
$0.50
Output Price per Million Tokens
GPT-5.3-Codex
$14.00
R1 0528
$2.15
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
GPT-5.3-Codex Quirks & Gotchas
No developer gotchas reported.
R1 0528 Quirks & Gotchas
No developer gotchas reported.