Shopify processed $9.3B in BFCM sales in 2023. At that volume, load balancing is not infrastructure trivia — it is the layer that determines whether your app stays up or takes merchants down with it.

Here are the five most critical load balancing decisions for Shopify app developers, with production-ready configurations.

Match the Algorithm to the Workload

Not all load balancing algorithms suit Shopify's traffic patterns.

AlgorithmUse CaseWhyRound RobinStateless API workersUniform request durationLeast ConnectionsWebhook worker poolsVariable job durationIP HashOAuth flows, WebSocketsSession continuity requiredWeighted Round RobinMixed-capacity fleetsProportional distribution

For most Shopify apps, round robin handles API requests and least-connections handles webhook workers.…