Claude Opus 4.8 vs GPT-5.5
Claude Opus 4.8 (Anthropic) vs GPT-5.5 (OpenAI), compared on price, context, speed and Arabic support. Both run on thalam through one OpenAI-compatible API, so you can switch between them with a single model id change.
Specs side by side
| Spec | Claude Opus 4.8 | GPT-5.5 |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Type | Text | Text |
| Context window | 1M | 1M |
| Max output | 128K | 128K |
| Input price | $5.00 / 1M | $5.00 / 1M |
| Output price | $25.00 / 1M | $30.00 / 1M |
| Speed | Medium | Medium |
| Arabic support | Strong | Strong |
Which should you choose?
- Anthropic's newest frontier model. Highest capability for complex reasoning, long-form, and agentic tasks
- OpenAI's flagship GPT-5.5. Top-tier general intelligence, coding, and agentic tasks with a 1M-token context
One OpenAI-compatible endpoint, one bill. Switch between them with a single model id change, pay per use, credits never expire.
Related comparisons
FAQ
What's the difference between Claude Opus 4.8 and GPT-5.5?
They are closely matched on the headline specs; the best choice depends on your workload. Both are available on thalam behind one OpenAI-compatible API.
Is Claude Opus 4.8 or GPT-5.5 cheaper?
They are priced similarly ($5.00 / 1M vs $5.00 / 1M). On thalam you pay per use with no subscription, so you can A/B them on cost with no commitment.
Can I use both Claude Opus 4.8 and GPT-5.5 with one API key?
Yes. thalam is OpenAI-compatible, so both models are reachable through the same endpoint. Switching between them is a one-line model id change, no code rewrite.