What is time-travel debugging?

This post introduces and explains the concept of time-travel debugging, also known as reverse debugging, detailing its history and implementation techniques (Record & Replay, Snapshotting, Instrumentation). It specifically highlights how Temporal's durable execution leverages a form of record & replay to enable time-travel debugging of production code. The post explains that durable execution records external inputs and state changes, allowing for deterministic replay of workflow executions on development machines. This provides a powerful debugging capability that goes beyond traditional debuggers and distributed tracing, allowing engineers to inspect any past state of a production workflow.