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One API Key for GPT, Claude & Gemini: The Multi-Model Gateway Guide (2026)
Shipping with more than one model usually means more than one account: separate keys, separate invoices, separate rate limits, and separate SDK quirks for OpenAI, Anthropic, and Google. A multi-model gateway collapses all of that into one key and one bill. Here's how it works and how to pick one.
The problem with one account per provider
- Three dashboards, three invoices, three sets of credentials to rotate.
- Prepaying each provider separately strands credit you can't move.
- Switching from GPT to Claude means new auth, new base URL, sometimes new request shape.
- No shared failover — if one provider has an incident, your app is down for those models.
What a multi-model gateway does
A gateway sits between your app and the model providers. You call one OpenAI-compatible endpoint with one API key, and the gateway routes each request to the right upstream based on the model name. Change model: "gpt-4o" to model: "claude-sonnet" and nothing else in your code changes.
What you get
| Without a gateway | With a multi-model gateway |
|---|---|
| 3+ API keys | 1 API key |
| 3+ invoices / prepaid balances | 1 wallet |
| Per-provider SDKs | One OpenAI-compatible SDK |
| No cross-provider failover | Automatic failover across upstreams |
| Per-provider spend tracking | One usage + spend view |
What to look for
- True OpenAI compatibility — so your existing SDK and prompts work unchanged.
- Model breadth — GPT, Claude, Gemini, Grok, Llama, DeepSeek, plus image/video if you need it.
- Prepaid vs postpaid — prepaid credit is easier to cap and budget than a monthly invoice.
- Per-key budgets and scoping — so a leaked key or a runaway job can't drain everything.
- Failover — if one upstream errors, the gateway should retry another automatically.
A prepaid, OpenAI-compatible option
SuperbAPI is one prepaid wallet for every major model: top up once, generate scoped keys, and call text, code, image, and video models through a single OpenAI-compatible endpoint — no subscription, no service fee, credit valid 12 months, with per-key budgets and automatic failover. Point any OpenAI SDK at the SuperbAPI base URL and pass your key.
Browse every available model →
FAQ
Can one API key really call GPT, Claude, and Gemini?
Yes — through an OpenAI-compatible gateway that aggregates providers. You send the model name; the gateway routes to the right upstream. One key, one wallet, many models.
Do I have to change my code to switch models?
No. With an OpenAI-compatible gateway you only change the model field; the endpoint and key stay the same.
Is prepaid or postpaid better for a multi-model API?
Prepaid credit is easier to budget and cap — you top up a fixed amount and draw it down, with no surprise invoice. Postpaid can be fine at scale but is harder to bound.
SuperbAPI is an independent aggregator and is not affiliated with, endorsed by, or partnered with any model owner. Third-party product names are used nominatively to describe compatibility and routing. Comparisons reflect our understanding at publication and may change.