How would you scale your past project to handle 10x traffic?

Frame a 10x plan around measurements rather than naming fashionable components. Establish requests per second, payload sizes, read/write mix, tail-latency SLOs, error budget, and the expected burst profile. Find the current bottleneck using traces, database metrics, and load tests. Typical early wins are caching safe read paths, making application instances stateless for horizontal scaling, indexing expensive queries, and moving slow noncritical work onto durable queues. For the data layer, explain when replicas relieve reads and when partitioning or write redesign is necessary, including consistency and operational costs. Add rate limits, backpressure, timeouts, idempotency, and dashboards before the traffic arrives. Roll changes gradually with capacity headroom and a rollback plan. A strong answer names the evidence that would trigger each next step rather than promising a single architecture solves every tenfold increase.