hotreloadable

Hotreloadable describes software components, modules, or systems that can incorporate code changes or configuration updates while running, without requiring a full process restart. The term is commonly used to describe development workflows that aim to shorten feedback loops by updating behavior in place.

Implementation relies on runtime capabilities such as dynamic module loading, in-memory patching, or replacing modules while preserving or carefully handling state. In web frontend development, hot reload is often achieved via hot module replacement (HMR) or fast refresh, integrated into build tools and frameworks. These techniques enable updated code to run alongside existing execution, with varying degrees of automatic state preservation and error handling.

Benefits of hotreloadable components include faster iteration, reduced downtime, and a smoother development experience. Limitations include that not all changes can be applied safely at runtime, some state may be lost or require cleanup, and production environments may disable hot reloading to maintain stability, security, or performance.

Examples exist across ecosystems: JavaScript tooling such as Webpack HMR and Vite support hot reload in web applications; .NET offers Hot Reload in recent runtimes; Java can use runtime instrumentation and class redefinition in certain setups; Python supports reloading modules via importlib.reload for dynamic workflows.

Design considerations for hotreloadable systems emphasize safety and predictability. Clear boundaries between reloadable and non-reloadable code help minimize side effects, provide robust fallback or rollback if a reload fails, ensure components are as idempotent as possible, and document which changes are compatible with live reload.