How Shopify Handles Black Friday Without Breaking

Episode notes

Lucas and Luna dig into the engineering behind Shopify's Black Friday infrastructure - specifically, how the platform absorbs 10,000 requests per second per store during peak traffic without cascading failures. They break down the shift from monolithic scaling to a 'cell-based' architecture where each merchant's data lives in an isolated shard, preventing one viral store from taking down the whole platform. Lucas explains the surprising bottleneck: not database queries, but TLS handshake overhead at the load balancer layer. Luna challenges whether this level of isolation creates operational complexity that offsets the reliability gains. They also touch on how Shopify's engineering team stress-tests with 'failure injection Fridays' and why the company chose to open-source parts of its sharding toolkit. The episode ends with a candid look at whether cell-based architecture is overkill for smaller platforms, and a quick nod to how listener support keeps the podcast ad-free.

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