Preparing Shopify for Black Friday and Cyber Monday

Summary

Shopify’s Production Engineering team prepares its platform and 600,000+ merchants for Black Friday and Cyber Monday traffic without interrupting service. Preparation combines controlled fault injection “game days,” synthetic load tests, and staged freezes: a feature freeze begins several weeks ahead, followed by a code freeze allowing only critical fixes during the event. The tests probe dependencies such as shipping providers and payment gateways, including latency, fallback behavior, and responses to datastore failures. After the 2018 weekend, Shopify reported nearly 11,000 orders per minute, around 100,000 requests per second for extended periods, and overall metrics about 1.8 times 2017 levels. The account concludes that fault injection, load testing, and disaster role-play improved readiness, while third-party downtime remains Shopify’s responsibility to merchants and buyers.

Takeaways

1. 1

   Game days test whether services behave reasonably when dependencies such as shipping providers become slow or fail, including whether fallback providers or hard-coded defaults work.

2. 2

   Synthetic load testing sends expected BFCM-scale traffic to applications to evaluate how systems and components behave under sustained request volumes.

3. 3

   Shopify uses a feature freeze and then a code freeze before BFCM to reduce workflow changes, bugs, and unexpected system interactions during peak traffic.

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