Why is my AWS Lambda cold start latency inconsistent across invocations?

Cold start variance usually comes from runtime choice (Java and .NET have materially higher cold starts than Python/Node.js) combined with package size — large deployment packages or many dependencies slow initialization.

Mitigation

Provisioned Concurrency eliminates cold starts for latency-sensitive functions at a fixed cost; for less critical paths, trimming dependencies and using Lambda SnapStart (Java) or a lighter runtime is usually more cost-effective.