GPT-5.1-Codex-Max vs Qwen3.5 Plus 2026-04-20
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-5.1-Codex-Max and Qwen3.5 Plus 2026-04-20.
GPT-5.1-Codex-Max
GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic...
Qwen3.5 Plus 2026-04-20
Qwen3.5 Plus (April 2026) is a large-scale multimodal language model from Alibaba. It accepts text, image, and video input and produces text output, with a 1M token context window. This...
Technical Specifications
| Specification | GPT-5.1-Codex-Max | Qwen3.5 Plus 2026-04-20 |
|---|---|---|
| Provider | OpenAI | Alibaba |
| Context Window | 400,000 tokens | 1,000,000 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 | beta |
| API Available | Yes | Yes |
| Released Date | 2025-12-04 | 2026-04-27 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5.1-Codex-Max
$1.25
Qwen3.5 Plus 2026-04-20
$0.30
Output Price per Million Tokens
GPT-5.1-Codex-Max
$10.00
Qwen3.5 Plus 2026-04-20
$1.80
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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-5.1-Codex-Max Quirks & Gotchas
No developer gotchas reported.
Qwen3.5 Plus 2026-04-20 Quirks & Gotchas
No developer gotchas reported.