OpenAI's GPT and Anthropic's Claude are the two frontier API families most teams weigh up. Both are excellent; they differ in temperament, pricing shape and ecosystem. The honest answer to "which one?" is usually "both, per task" — and a gateway makes that free.
Key takeaways
- GPT and Claude are close on raw capability; pick per task, not forever.
- Claude tends to shine on long-context reasoning and careful instruction-following; GPT on breadth, tooling and ecosystem.
- Both are OpenAI-compatible through a gateway, so you can A/B them with a one-word change.
- You don't have to commit your whole codebase to one vendor.
The short version
| OpenAI (GPT) | Anthropic (Claude) | |
|---|---|---|
| Flagship | GPT-6 Astra | Claude Opus 5 |
| Strengths | Breadth, tooling, ecosystem, multimodal | Long-context reasoning, instruction-following, careful output |
| Context | Large (~1M on flagship) | Large (1M on Opus 5) |
| Everyday workhorse | GPT-5.6 Sol / Terra | Claude Sonnet 5 |
| Cheap & fast | GPT-5.x mini / nano | Claude Fable 5.1 / Haiku 4.5 |
Prices move often — don't trust a number in a blog post. The models page reads live from the same catalog the gateway bills against.
Where each one pulls ahead
Reach for Claude when…
- You're feeding in very long documents and need the model to hold the thread.
- You want tight instruction-following and fewer "creative" deviations.
- Careful, auditable reasoning matters more than raw speed.
Reach for GPT when…
- You lean on a broad tooling ecosystem and multimodal inputs.
- You want the widest menu of model sizes to tune cost vs latency.
- You're already standardized on OpenAI-shaped requests.
You don't have to choose
This is the part most comparisons miss. Through an AI gateway, both families are OpenAI-compatible — so running Claude for one feature and GPT for another is a single string per call, on one key and one bill.
// Same client, same request — switch families by name.
await ai.chat.completions.create({ model: "gpt-6-astra", messages });
await ai.chat.completions.create({ model: "claude-opus-5", messages });The cleanest way to decide is to A/B both in production on your real prompts. A gateway makes that a config change, not a second integration.
How to actually pick
- Start with the everyday workhorse of either family (Sonnet 5 or GPT-5.6).
- For your hardest task, trial both flagships head-to-head — see GPT-6 Astra vs Claude Opus 5.
- Push high-volume, latency-sensitive paths down to a cheap model. (Model routing explains how.)
Build on the one that fits each task — and keep the option to switch. See every model, side by side.