PWAs

Progressive web apps (PWAs) are web applications designed to combine the reach of the web with the user experience of native apps. Built with standard web technologies (HTML, CSS, JavaScript), PWAs employ modern web capabilities to behave like installable apps on desktops and mobile devices while remaining accessible via a URL and requiring no separate app store.

Key technologies include service workers, which enable offline functionality and background syncing; a web app manifest, which provides metadata such as name, icons, and start URL; and HTTPS, which secures communication. PWAs emphasize responsive design to run on a range of devices and screen sizes and use the Cache API and other progressive enhancement techniques to improve performance.

Features include offline or low-network operation, installability from the browser, and a home screen or app launcher presence on supported devices. They offer app-like navigation and transitions, push notifications where available, and the ability to update automatically through the web server.

Advantages include cross-platform compatibility, simplified distribution, lighter maintenance than separate native apps, and improved discoverability via the web. Limitations include varying support for certain native APIs across platforms, potential performance constraints on older devices, and reliance on users having an updated browser. Some device features (such as certain sensors or system-level integrations) may be inaccessible.

PWAs have seen broad adoption across industries, with major browsers supporting service workers and web app manifests. Popular examples include Twitter Lite and Pinterest, which use PWAs to deliver fast, reliable experiences even on slower networks. Developers often use performance and best-practice audits to optimize PWAs for speed and reliability.