Compare models
Pick up to 4models. Specs render side-by-side. Share the URL — it's stateless.
 o3OpenAI | GPT-5.5 OpenAI |  DeepSeek-V4-ProDeepSeek | |
|---|---|---|---|
| Vendor | OpenAI | OpenAI | DeepSeek |
| Family | o-series | GPT | DeepSeek |
| Release date | 2025-04-16 | 2026-04-23 | 2026-04-22 |
| Context window | 200,000 tokens | 400,000 tokens | 1,000,000 tokens |
| Parameters | — | — | 1.6T (49B active) |
| Modality | text, vision | text, vision, audio | text |
| License | proprietary | proprietary | MIT |
| Source | proprietary | proprietary | open weights |
| Description | Reasoning-focused model in the o-series. | OpenAI's smartest and most intuitive model — successor to GPT-5, with major coding, research, and document workflow gains. GPT-5.5 Pro variant also available for heavier reasoning. | DeepSeek's flagship open-weight MoE. 1.6T parameters with 49B activated, 1M-token context, and a hybrid attention scheme (CSA + HCA) that delivers long-context inference at ~27% of V3.2's FLOPs. |
| Links |
