5 lessons from Netflix on surviving traffic surges
Sure, Netflix has had its fair share of outages (we've all seen the meltdowns on X). But most of the time, even when traffic spikes unpredictably, the app stays rock solid.
So how does it survive massive traffic surges, regional failures, and cloud chaos—while other apps crumble the moment a new product launches?
The answer is battle-tested resilience strategies. Netflix doesn't scale blindly: it expects failure, and engineers around it. From smart load shedding to multi-region traffic shifting, Netflix's architecture is designed to absorb shocks and recover fast. And every developer can learn from it.
In today's newsletter, we’ll break down:
Why load spikes happen (and why they’re not always predictable)
How Netflix auto-scales smarter—beyond basic CPU-based scaling
The secret behind prioritized load shedding (a survival tactic for high-scale services)
How Netflix shifts traffic across AWS regions without causing a meltdown
What developers can learn from Netflix’s engineering playbook—even if you’re not running a global streaming empire
Let’s pull back the curtain and see what really keeps your binge-watching experience smooth.
What causes load spikes?
Load spikes are sudden and unpredictable surges in user traffic that can overwhelm infrastructure if they're not handled efficiently. A few cases can cause load spikes:
Regional failover: Region failure is a rare issue but still inevitable. Once a region goes down, all the services interacting with it will go offline, too, ultimately affecting businesses. In Netflix's case, service disruption for millions of users is unacceptable when there is no SLA for the region’s availability again. Shifting the traffic to another region can cause a load spike.
Long and short spikes: Short-load spikes are temporary traffic surges that last a few seconds to minutes. Retries or some device bug often cause these. Long-load spikes are periods of high traffic that last for hours or even days. They typically occur during major events, such as the launch of a new title or the downtime of another streaming site.
The diagram above shows how the long surges occur (expected and unexpected) in the Netflix system.
These spikes can cripple infrastructure if not handled properly. But Netflix has built its entire architecture to absorb these shocks—let’s see how.
How Netflix works
The secret lies in its multi-region architecture, predictive scaling, and microservice resilience. Instead of reacting to failure, Netflix designs for it. Let’s take a look at how their system is built to handle chaos at scale.
