When should you use Apollo Router instead of Apollo Gateway?

For most new federated projects today, Router is the better starting point. A few concrete signals make the case even stronger:

• High request volume – Router's Rust runtime handles far more requests per second with lower and more consistent latency than the Node.js Gateway.
• Subscriptions – if the graph needs federated GraphQL subscriptions, Router supports them natively; Gateway's support is limited at best.
• Operational footprint – Router ships as a single precompiled binary/container with a smaller memory footprint than a Node process.
• Extensibility needs – if custom request/response logic is needed, Router's Rhai scripting or external coprocessors are the actively developed extension points.

The main reason to stay on Gateway a bit longer is an existing investment in JS-based Apollo Server plugins that haven't been ported yet — but Apollo's own guidance is to plan a migration regardless, since new federation capabilities are increasingly Router-first.