o3 (Fast) vs GPT-5.3 Chat
Both have similar output pricing, while o3 (Fast) offers a larger context window. Choose o3 (Fast) or GPT-5.3 Chat based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | o3 (Fast) | GPT-5.3 Chat |
|---|---|---|
| Provider | Vercel AI Gateway | Vercel AI Gateway |
| Input / 1M tokens | $3.50 | $1.75 |
| Output / 1M tokens | $14.00 | $14.00 |
| Context window | 200K | 128K |
| Parameters | — | — |
| Open weights | No | No |
| Released | Apr 2025 | Mar 2026 |
FAQ
Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.