Profiling is a crucial tool for developers to ensure their code meets performance goals, and it's especially important in production where predicting slow lines of code can be challenging. Profiling tools capture a snapshot of resource usage, known as a profile, which allows developers to directly map resource usage to specific lines of code. While tracing is another performance monitoring tool that tracks the flow and timing of requests, profiling provides more granular information about internal issues causing slowdowns. There are different types of profilers, including ad hoc, continuous, and transaction-based profiling, each with its own strengths and weaknesses. Profiling can be done continuously, ad hoc, or in a hybrid manner, and it can have varying levels of performance overhead depending on the approach used. Deterministic and sampling profilers collect profiles differently, with deterministic profilers capturing all function calls and exception events for accuracy, while sampling profilers prioritize performance by collecting samples at regular intervals. Overall, profiling is an essential tool for developers to optimize their code and ensure a good user experience.