Scaling a Streaming Platform to 5 Million Concurrent Users
Key outcomes
The Challenge
A fast-growing streaming platform was preparing for a major live event expected to drive an unprecedented spike in concurrent viewers. Previous live events had caused partial outages affecting tens of thousands of users, resulting in significant subscriber churn and reputational damage.
The engineering team needed confidence that their infrastructure could handle 5 million concurrent users—ten times their previous peak—while maintaining sub-200ms response times for key API endpoints.
The Solution
TestDel's performance engineering team designed and executed a comprehensive load testing programme using k6 and AWS CloudWatch. We began with baseline performance profiling to establish current capacity limits, then worked with the client's DevOps team to identify and resolve four critical bottlenecks in the video delivery pipeline.
We simulated realistic user journeys at progressive load levels—500k, 1M, 2.5M, and 5M concurrent users—identifying failure thresholds and tuning the auto-scaling configuration to respond correctly under load. We also implemented ongoing synthetic monitoring to detect performance regressions post-launch.
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