Progressive Web Apps in 2016: The Mobile Web Revolution
Deep dive into Progressive Web Apps (PWAs) and their impact on mobile web development and user experience
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Technology
• 4 min read
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Updated: May 15, 2016
Core Concepts
1. PWA Architecture
The architecture of a Progressive Web App (PWA) is defined by three main components:
- Service Worker: This component is responsible for caching, offline functionality, and push notifications. It acts as a proxy between the network and the application, allowing for the interception and modification of network requests. This enables PWAs to function offline or with a slow network connection, providing a seamless user experience.
- Manifest: This is a JSON file that provides metadata about the PWA. It includes information about the app’s icons, display mode, and orientation. The manifest file is used by the browser to understand the PWA’s capabilities and to provide a native app-like experience. It also enables the PWA to be installed on the user’s home screen, making it easily accessible.
- Features: These are the key features that make a PWA stand out. They include installability, responsiveness, and connectivity. Installability allows users to add the PWA to their home screen, making it easily accessible. Responsiveness ensures that the PWA adapts to different screen sizes and devices, providing an optimal user experience. Connectivity enables the PWA to function offline or with a slow network connection, ensuring that users can continue to use the app even in areas with poor network coverage.
Additionally, PWAs also include other important features such as:
- Push Notifications: These allow the PWA to send notifications to users, even when the app is not running. This enables the PWA to re-engage users and provide them with important updates or information. Push notifications can be used to inform users about new content, special offers, or critical updates, ensuring that they stay engaged with the app.
- Background Sync: This feature enables the PWA to synchronize data in the background, ensuring that the app is always up-to-date and that users have access to the latest information. Background sync is particularly useful for apps that require real-time data, such as news or social media apps, where users expect to see the latest updates as soon as they open the app.
- Web App Install Banners: These are banners that appear in the browser, prompting users to install the PWA on their home screen. This makes it easy for users to add the PWA to their device, providing a native app-like experience. Web app install banners are an effective way to encourage users to install the PWA, making it easily accessible and increasing user engagement.
- Offline First: This approach prioritizes offline functionality, ensuring that the PWA provides a seamless user experience even without a network connection. Offline first PWAs cache critical resources and data, allowing users to continue using the app even in areas with poor or no network coverage. This feature is particularly important for apps that are used in areas with unreliable network connectivity.
- HTTPS: PWAs require HTTPS to ensure that all data transmitted between the app and the server is encrypted and secure. This provides a secure environment for users to interact with the app, protecting their data and ensuring that the app is trustworthy. HTTPS is a critical component of PWAs, as it enables the use of service workers and ensures that the app is secure and trustworthy.
- App Shell Architecture: This architecture separates the application’s shell (the basic user interface) from its content. The app shell is cached locally, allowing the PWA to load quickly and provide a seamless user experience. The content is then loaded dynamically, ensuring that users have access to the latest information. This approach enables PWAs to provide a fast and seamless user experience, even on low-end devices or with slow network connections.
