An isolated computing environment, separate from production systems, dedicated to software engineering activities. This can take the form of a physically distinct development machine, a virtualized instance running on hypervisor technology, or a containerized application sandbox.
The key purpose is to provide developers with a dedicated, non-production workspace for safely writing, testing and debugging code changes without risking unintended impacts to live operational systems and data. Using these logically partitioned and controlled development environments prevents coding activities from inadvertently disrupting or tainting production resources.
Software modifications can be built, integrated and validated within these segregated application workspaces before being approved for deployment into production environments. This critical separation of duties between dev and production environments enables more secure, controlled software delivery lifecycles.