PACKAGE · STATE MANAGEMENT

mobx

Simple, scalable state management.

WEEKLY DOWNLOADS 3.2M
STARS 28.2K
FORKS 1.8K
OPEN ISSUES 66
GZIP SIZE 15.4 kB
UNPACKED SIZE 4.7 MB
DEPENDENCIES 1
LAST UPDATED 10mo ago
DOWNLOAD TRENDS

mobx downloads — last 12 months

Download trends for mobx1 download series from Aug 2025 to Jul 2026. Use left and right arrow keys to inspect monthly values.04.3M8.6M12.9M17.2MAug 2025NovFebMayJul 2026
mobx
ABOUT MOBX

MobX is a state management library designed to simplify the process of managing and synchronizing application state, especially in complex user interfaces. It tackles the common challenge of predictable state updates and reactivity, allowing developers to focus on building features rather than on intricate state management logic.

The core philosophy behind MobX is to make state management as simple and scalable as possible by leveraging observable data structures and reactive programming principles. It aims to be intuitive for developers, particularly those working with JavaScript frameworks, by minimizing boilerplate code and enabling automatic dependency tracking.

Key to MobX's approach are its observable decorators or functions, such as `makeObservable` or `makeAutoObservable`, which wrap your data models. When these observables are accessed within reactions (like computed values or component renders), MobX automatically tracks these dependencies. Changes to observables then trigger only the necessary re-renders or re-computations, ensuring efficient updates.

MobX integrates seamlessly with various JavaScript frameworks and libraries, with particularly strong support and common usage patterns found within the React ecosystem. It provides hooks like `useObserver` for React components, enabling functional components to react to state changes automatically. Its core principles are also applicable in vanilla JavaScript or other UI frameworks.

With a weekly download count of 3.2 million and 28.2K GitHub stars, MobX is a mature and widely adopted state management solution. Its unpacked size is 4.7 MB, but its gzipped bundle size is a lean 15.4 kB, making it a performant choice for applications of all sizes. The library has been actively maintained, with version 7.0.0 released recently, indicating ongoing development and support.

While powerful, developers should be aware that MobX's automatic nature can sometimes make it harder to trace exactly why a particular piece of state changed without careful observation and debugging. Understanding the reactivity system and how observables, actions, and reactions interact is crucial for effectively managing complex state flows and avoiding unexpected behavior.

WHEN TO USE
  • When managing complex, interconnected application state that requires automatic propagation of changes.
  • When you want to minimize boilerplate code for state updates and UI re-renders using observable patterns.
  • When building interactive UIs with JavaScript frameworks like React, leveraging hooks like `useObserver` for automatic component updates.
  • When your application state involves multiple related data models that depend on each other and require synchronized updates.
  • When you need to create computed values that automatically update based on changes in underlying observable state.
  • When aiming for a reactive programming paradigm where state changes automatically trigger side effects or UI refreshes.
WHEN NOT TO USE
  • If you only need simple, isolated client-side state — React's built-in `useState` along with context might suffice.
  • When a strictly unidirectional data flow with explicit action dispatching is a core architectural requirement.
  • If you prefer a state management solution with a more explicit and manual control over every state mutation and update.
  • When integrating into environments that strictly prohibit observable data patterns or require a more functional, immutable update approach without external libraries.
  • If your application state is minimal and primarily consists of UI-specific toggles and form inputs.

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