Understanding Progressive Web Apps (PWAs)

Introduction

In recent years, the adoption of Progressive Web Apps (PWAs) - web applications that behave like native apps when installed - has become a prominent trend across industries.

• These applications combine the reach of the web with app-like experiences, offering users the convenience of installation, offline access and push notifications without relying on app stores.
• Major technology companies such as Google, Spotify, Facebook, Instagram, X (formerly Twitter) and Trip.com, have integrated PWAs into their platforms - some alongside native apps, others as primary offerings.

When a website is PWA-enabled and meets the installability criteria (including serving content over HTTPS, registering a service worker and providing a valid Web App Manifest), an install prompt typically appears in Chromium-based browsers, allowing users to install the PWA directly onto their device home screen.

Developer Perspective: Build Once, Deploy Everywhere

From a developer’s perspective, PWAs offer a cost-effective, cross-platform solution with lower development overhead and improved agility compared to maintaining separate native apps.

Lower Development & Maintenance Cost

• PWAs are built using standard web technologies (HTML, CSS, JavaScript) and work across desktop, Android and iOS with minimum platform-specific modifications.

Native-like Capabilities

• While PWAs do not have full access to native APIs, they support many key features, including
• Push notifications
• Offline access
• Install prompts and home screen shortcuts
• Responsive, full-screen experiences.

Streamlined Updates

• Unlike native apps, PWAs do not require app store approvals for updates.
• Developers can push updates instantly via the web, helping to eliminate version fragmentation across devices.

Consistent User Experience

• A single PWA codebase can deliver a uniform experience across all devices, improving maintainability and reducing complexity.

User Experience and Concerns: Security and Trust

PWAs provide a seamless full-screen interface, often hiding the browser’s address bar and UI elements.

• This enhances immersion but may lead some users to confuse PWAs with fully vetted native applications, raising security concerns.

Unlike native apps, which undergo review before being listed in Google Play or the App Store, PWAs are installed directly from the browser. This convenience comes with potential risks:

• Phishing attacks via fake or lookalike domains
• Abuse of granted permissions (e.g., geolocation, camera, microphone)
• Data theft through insecure storage or cookie hijacking
• Redirection to malicious APKs under the guise of “full version” upgrades

However, PWAs are sandboxed and governed by browser-level security policies, meaning they are isolated from the host operating system and other applications.

• They cannot directly access sensitive system-level resources, making them inherently more limited and in many ways safer than misconfigured or malicious native apps.

Security Architecture: PWAs vs Native Apps

Filesystem Access

• PWAs are restricted to browser-managed storage like IndexedDB, localStorage and CacheStorage, with no access to the file system.
• Native apps, with user permission, can access internal and external device storage.

Installation and Distribution

• PWAs are installed directly from the browser when installability criteria are met. No app store submission is required.
• Native apps are installed through app stores, where they undergo a formal security and policy review.

Permissions Handling

• PWAs request sensitive permissions (camera, mic, location) via real-time browser prompts. These can be revoked at any time through browser settings.
• Native apps request permissions at install time or during runtime, with broader scope and deeper access to device features (though newer OS versions offer more granular controls).

Sandboxing and Isolation

• PWAs operate within the browser sandbox, isolated from the OS and other apps.
• Native apps are sandboxed by the OS, but their deeper integration can pose more risk if compromised.

Update Mechanism

• PWAs update automatically when assets or service workers change. No user interaction is needed.
• Native apps require manual updates or app store approval, depending on platform settings.

Security Enforcement

• PWAs benefit from mature web security practices like the Same-Origin Policy, Content Security Policy (CSP) and strict HTTPS requirements.
• Native apps rely on platform-level protections, which vary by OS and are subject to developer implementation quality.

In essence, PWAs are fundamentally constrained by the browser’s security model.

• Installing a PWA is more akin to saving a powerful, offline-capable bookmark than installing a fully privileged native application.

Risk to Consider: Web-Based, Not Risk-Free

While PWAs inherit strong web security mechanisms, they remain vulnerable to certain classes of web-specific attacks:

• Man-in-the-middle (MITM) attacks if HTTPS is not enforced or misconfigured.
• Cross-site scripting (XSS) or code injection vulnerabilities in poorly secured web apps.
• Domain spoofing, where attackers mimic a legitimate brand to trick users into trusting a fake app.
• Phishing attacks, designed to steal user credentials, identity data or financial information.
• Malicious APK sideloading, where users are tricked into installing unverified apps outside of the Play Store.

That said, the risk of using a PWA is no greater than visiting the same website in a browser.

• The install action itself does not introduce new vulnerabilities unless it is abused to lure users into installing malicious content from external sources.

Best Practices: Developer and User Responsibility

Developer Guidelines

• Serve all assets over HTTPS
• Keep dependencies updated and monitor for vulnerabilities
• Use robust Content Security Policies (CSP) and HTTP security headers
• Regularly audit for XSS and injection flaws
• Configure the Web App Manifest properly (scope, icons, display mode)
• Implement a robust service worker caching strategy to ensure reliable offline access and fast performance

User Guidelines

• Install PWAs only from trusted domains
• Do not sideload APKs offered by unknown or unverified web apps
• Be cautious with permissions (e.g. location, contacts) - only allow what is needed for functionality
• Revoke permissions through browser site settings if something feels suspicious
• Keep your browser and OS updated to stay protected against known vulnerabilities

When in doubt, users can always access the PWA as a regular website without installing it to maintain maximum transparency.

When Native Apps are Still Preferable

Despite the growing power of PWAs, certain use cases still benefit from native apps:

Heavy hardware or API integration

• Apps requiring Bluetooth, NFC, biometric authentication or advanced camera features.

High-performance gaming

• Real-time 3D rendering or low-latency gaming is still better suited to native environments.

Complex background tasks

• Apps that need to perform complex, long-running tasks in the background (e.g., audio processing, data synchronization) may find native APIs more reliable and powerful.

App store visibility

• For marketing, discovery or monetization, listing on Google Play or the App Store is beneficial.

Established user base

• Some companies retain native apps due to legacy support or deep platform-specific features.

Summary

Progressive Web Apps strike a balance between the reach of the web and the functionality of native apps.

• With offline support, push notifications, installability and app-like UX, PWAs are increasingly seen as a viable solution for modern app development.
• Security risks associated with PWAs are real but manageable, due to the robust protection provided by browser-enforced sandboxing, strict HTTPS requirements and adherence to modern web security standards.

As browser APIs and operating system support continue to advance, PWAs are poised to become increasingly powerful, further narrowing the gap between traditional web applications and native apps.

• Far from being a passing trend, PWAs represent a forward-compatible, scalable and open-standard-based approach to app delivery - well-suited for the future of cross-platform user experiences.

External Links

• More than 250 malicious apps are spreading info-stealing malware on Android and iOS — delete these right now, 2025
  
• Protecting Yourself from Malicious Web Apps: What You Need to Know, 2024