Cold Start

In serverless computing, a cold start is the additional time the function takes to respond to the first request it gets following a period of inactivity.

When a function is triggered for the first time, the cloud provider needs to allocate resources and set up the execution environment, usually spinning up the micro virtual machine running the function code, and initialising all dependencies. This can cause a delay in response time.

Cold-starts can affect the performance of the application, and result in a poor user-experience.

However, it is important to note that cold starts usually represent a tiny fraction of all invocations for applications with decent traffic.