OpenAI's high-capability model optimized for deep reasoning and accuracy on complex, high-stakes workloads.
Open-source 1.6T-parameter MoE with 49B active, built for advanced reasoning and long-horizon agents.
No shared agent demos for these models yet.
No captured outputs for these models yet.
Based on the Capability Index, GPT 5.5 Pro scores higher (91.8 vs 81.6). However, "better" depends on your use case — pricing, speed, context window, and specific capability needs all matter.
DeepSeek V4 Pro has a lower blended cost. GPT 5.5 Pro: $30.00 input / $180.00 output. DeepSeek V4 Pro: $0.43 input / $0.87 output.
GPT 5.5 Pro has a larger context window: GPT 5.5 Pro supports 1.1M tokens vs DeepSeek V4 Pro at 1M tokens.
GPT 5.5 Pro supports vision/image input, but DeepSeek V4 Pro does not.
Key differences: GPT 5.5 Pro has a notably higher capability index (10.2 point gap); DeepSeek V4 Pro is significantly cheaper; only GPT 5.5 Pro supports vision input. Compare full specs on this page.
If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both GPT 5.5 Pro and DeepSeek V4 Pro for free on idapt.app to see which performs better for your specific needs.