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What Is an LLM API Gateway?

An LLM API gateway is a single endpoint in front of many model providers. You keep one API key, one bill and one integration — the gateway handles routing, metering and compatibility behind it.

The five things a gateway actually does

• Unified interface — every model speaks one dialect (usually OpenAI's). Swap model: "deepseek-v4-pro" for "glm-5.2" and nothing else changes.
• One key, one bill — instead of N provider accounts, N payment methods, N invoices.
• Per-token metering — usage counted from the upstream's own accounting, including cached-input discounts, with an audit trail per request.
• Fallback & stability — if a provider throttles, the gateway can retry or reroute instead of failing your request.
• Access where you aren't welcome — some frontier labs make direct access hard for developers outside their region (phone-number signup, domestic payment rails). A gateway handles onboarding and billing in the developer's own currency.

Direct API vs gateway vs router

	Direct provider API	Gateway	Multi-model router
One integration	One per provider	Yes	Yes
Billing	Provider's terms	Gateway's, USD	Marketplace credits
Metering transparency	Provider dashboard	Per-request audit trail	Varies
Model catalog	One vendor	Curated vendors	Hundreds of models
Pricing	Official	Often below official	Official + fee

When a gateway is worth it

You use models from more than one lab. DeepSeek for reasoning, GLM for Chinese support tickets, Kimi for long documents — the moment you'd otherwise maintain three SDK integrations, a gateway pays for itself in engineering time.

You bill your own customers for AI. If your product resells model output, you need per-request cost attribution. A gateway that exposes an audit trail (every request queryable by id) is the difference between "roughly this month's bill" and line-item accounting.

Official pricing moved against you. When a provider shifts to peak/off-peak pricing (as DeepSeek did in August 2026), a gateway with flat pricing protects your margins — and your roadmap from surprise re-pricing.

How Bridge does it

Bridge is purpose-built for one category: Chinese frontier models for global developers. One OpenAI-compatible endpoint (/v1), USD billing via Stripe, flat prices from a live price table, cached-input billing at 1/10, and a reconciliation page for every request. Start with $1 free credit — no phone number required. Compare the models in our full comparison or run the numbers in the cost calculator.

Get $1 free credit → try the gateway