What is PWA? A Guide on Progressive Web Apps Features, Architecture, Examples

Welcome to the world of Progressive Web Apps (PWAs), where the boundaries between web apps and mobile apps blur. PWA represents a strategic approach to web development that combines the accessibility of a web app with the functionality of a mobile app. Blending the best of both worlds, PWAs deliver an immersive user experience, characterized by fast loading times, offline functionality, and device-specific adaptability.

The biggest advantage of a Progressive Web App though, seems to be its profitability. PWA will make your product available for both web and mobile users with a single codebase, which can lead to increased traffic and a higher conversion rate.

In this article, we’ll delve into the essential attributes of Progressive Web Apps, discussing their architecture, features they offer, and real-world examples that demonstrate their effectiveness.

What is a Progressive Web App (PWA)?

Before jumping straight to the PWA definition, we need to answer the primary question – What does PWA stand for? As you can see in the headline, PWA is an acronym for Progressive Web App, where “progressive” indicates employing a method of progressive enhancement to ensure basic web functionality for everyone while incrementally adding richer features for users with advanced, modern browsers.

Now, for those not yet familiar with what are Progressive Web Apps, the simplest explanation is that it’s a type of application software delivered through the browser intended to work on both desktop and mobile devices.

The core appeal of PWAs lies in their ability to mimic app like features. They are fast, engaging, and reliable, even on a slow connection or offline. Outside of that, Progressive Web Apps operate directly through a web browser and, unlike native apps, don’t need to be downloaded and installed on user’s mobile device. Yet, an icon representing a Progressive Web App can still be added to the user’s screen, like in the case of a native mobile app.

Long story short, PWAs use modern web capabilities to deliver enhanced performance and user experience that rivals native mobile apps.

Key Progressive Web Apps Features

Above, we mentioned some of Progressive Web Apps’ capabilities. Now, let’s discuss them in more detail to fully understand how they make PWAs an attractive option for developers and businesses alike, especially in comparison to native apps.

Offline-first App

A Progressive Web App works as an offline-first application, meaning users work offline or with a poor internet connection. It is possible due to the operations made by service workers that behave like a proxy between the Internet and the user’s tab.

A service worker is a small script that can handle offline mode to previously visited web apps. Actually, mobile and web browsers run it separately from the main thread, intercepting network requests, caching, and retrieving resources from the cache. Additionally, service workers are responsible for delivering push notifications, enabling a Progressive Web App to send timely and relevant updates to users just like a native mobile app.

When users add the app icon to the home screen of a desktop or mobile device, they can open it anytime on a mobile browser and the app doesn’t even require updating. This impeccable offline functionality significantly increases the availability of the application and makes it easier to use, which can result in increased traffic and, thus, higher profits.

Native Components

PWA is a well-developed technology that uses components similar to those incorporated into a native app user interface. It means that a vast majority of buttons, animations, and other elements used in a Progressive Web Application resemble their native counterparts. Progressive Web Apps also leverage hardware tools, such as Bluetooth, accelerometer, gyroscope, and so on. That is why an average user does not see any difference between a PWA and a native mobile app.

Mobile-first Approach

There is a strict connection between Progressive Web Apps and a mobile-first approach. The latter is Google’s policy that was prompted by the rapid switch in the devices used by Internet users. As the majority of internet traffic is generated by mobile devices, from 2021 onward Google has been indexing pages with dedicated mobile versions or using technologies such as RWD or PWA prior to those that don’t. 

Since this is a requirement made by a major search engine on the market, conforming to this regulation is the best option. Otherwise, your app may stop appearing in search results and, consequently, lose traffic. With a Progressive Web App, you can reach both desktop and mobile users with just one solution and avoid this undesirable scenario.

Optimized Loading Time 

Progressive Web Apps are based on service workers that allow for retrieving resources concerning the previously visited site from the cache. This function reduces the amount of time required for the rendering of the content.

Why is loading time so important? Well, users are usually impatient and frequently drop the idea of revisiting a site if it opens slowly. Thanks to the optimization, you can meet their expectations, avoiding the loss of prospective customers.

Strict Security Standards

HTTPS is another of Google’s requirements and a must for every website nowadays. This protocol secures the confidentiality of personal data integrated between the user and the site. Thanks to the HTTPS connection, PWA addresses the customer’s demands concerning privacy. The security of your app may naturally improve your trustworthiness and, consequently, increase interest in your product.

Basics of Progressive Web Apps

There’s no doubt that PWAs offer a groundbreaking solution. By implementing a PWA, you can acquire the accessibility of a web page with the robust features of mobile applications, all in one. But what’s the history of this technology, how it works, and how to approach the development of a Progressive Web Application? Let’s find out.

History of PWAs

The concept of a PWA first emerged in 2015 when Google engineers Alex Russell and Frances Berriman coined the term. They introduced the idea as a solution to the limitations of mobile web experiences at the time, which often lacked the speed and features of native apps.

Since then, PWA development has gained significant momentum as it demonstrates a compelling alternative to native app development, promising ease of coding and maintenance, reduced costs, and improved user engagement.

How Progressive Web Apps Work?

PWAs function by taking advantage of modern web capabilities to deliver a native app like experience on mobile devices. Key components include:

• Service Workers: Scripts that run in the background and enable features like push notifications, background data syncing, and offline functionality.
• Web App Manifest: A JSON file that allows developers to control how their app appears to the user and how it can be launched. It defines the icons, page navigation, and what the application will look like when it’s launched from the home screen.
• Application Shell Architecture: This model ensures users have a smooth, app-like user interface with robust performance. The shell is cached on the user’s device upon the first visit, enabling instant, offline-capable future interactions.

Why To Use PWAs?

Progressive Web Apps offer several advantages that make them a strategic choice for businesses aiming to enhance their online presence. Here are some key reasons to consider using PWAs:

1. Improved User Experience: PWAs provide a fast, smooth, and app-like experience on the web. They are designed to work seamlessly across all platforms and devices, delivering consistent functionality and aesthetics, which can significantly improve user satisfaction and retention.
2. Cost-Effective Development: Developing a PWA can be more cost-effective than creating native apps for multiple platforms (web, iOS, Android, etc.). Since PWAs are built using standard web technologies, they allow you to maintain a single codebase for all platforms, reducing development and maintenance costs.
3. No App Store Dependencies: Progressive Web Apps do not need to be downloaded from app stores. They can be easily discovered and shared via a URL, avoiding the complexity and restrictions of app store approvals, updates, and fees. This direct access can help increase adoption rates and reduce time to market.
4. Push Notifications: PWAs support push notifications, allowing businesses to effectively re-engage users with personalized content and updates. This can increase engagement and keep your users informed about new products, services, or promotions.
5. SEO Benefits: Since Progressive Web Apps are part of the web, they are indexed by search engines. This can significantly improve your visibility and drive more organic traffic compared to traditional native apps that reside on users’ mobile phones.

How to Build a PWA?

Building a Progressive Web App involves several steps that align closely with traditional web development but with additional considerations for a more native app like experience. If we were to enumerate the subsequent steps during the PWA development process, the list would include:

1. Planning: Define the purpose and main functionality of your PWA. Consider the needs of your target audience and how features like offline accessibility and push notifications could benefit them.
2. Development: Use common web technologies like HTML, CSS, and JavaScript to create your app. Implement a service worker for handling offline work and background tasks.
3. Manifest File: Create and link a web app manifest file that specifies how your app should behave when installed on a user’s device.
4. Testing: Test your PWA on various devices and under different network conditions to ensure it is responsive and reliable.
5. Deployment: Deploy your PWA on a secure server with HTTPS and monitor its performance and user engagement to make iterative improvements.

Benefits of PWAs

By building web apps with the use of PWA, you may seriously hit the jackpot. Progressive Web Application technology offers immense opportunities, particularly for businesses looking to boost performance while minimizing costs and expanding their reach. The list of benefits could be long, but to get you a hint of its capabilities, we would enumerate:

• Low development cost
• SEO-friendliness
• Cross-platform compatibility
• Offline accessibility
• Fast time-to-market

For a deeper understanding, explore our detailed article on the benefits of Progressive Web Apps.

PWA Technology Requirements

Progressive Web Apps use a mix of advanced web technologies to deliver an experience that feels like a native app right in the web browser. If you’re considering building a PWA, it’s important to understand the technology requirements that make these apps so effective.

Service Workers

As mentioned earlier, service workers are the wizards behind the curtain for PWAs, managing features like offline access, background syncing, and push notifications. They help manage data caching and retrieval, giving your app native-like capabilities, such as working offline.

Web App Manifest

Think of the web app manifest as your app’s ID card. It’s a simple JSON file that tells browsers how your app should look on the home screen and how it should launch. You can customize your app’s name, the initial URL it opens, its colors, icons, and even the screen orientation. This little file is key to making your PWA feel integrated and seamless on all user devices.

HTTPS

Using HTTPS isn’t just good practice, it’s a must for a PWA. This ensures that all communications between your user’s browser and your server are encrypted and secure. It’s essential not only for protecting sensitive information but also for the smooth functioning of service workers.

Responsive Design

To ensure that everyone has a great experience regardless of their device, a PWA design needs to comply with responsive design best practices. This includes using flexible layouts and media queries to adapt your interface to any screen size or device, making sure your app looks good and works well whether it’s on a phone, tablet, or desktop.

Push API

To keep users coming back, a PWA can use the Push API alongside service workers to send notifications. This lets your app deliver timely and relevant updates to users, even when they’re not actively using your app. It’s a fantastic tool for re-engaging people with personalized alerts and information.

IndexedDB

For storing data right in the user’s browser, a PWA often turns to IndexedDB. This is a robust, low-level API perfect for saving everything from user settings to large amounts of data offline. It’s a cornerstone for ensuring your app can work offline, keeping critical features always accessible.

PWA Architecture

If you go further into details concerning PWA, you will discover that these apps are developed according to two different architectural styles. They differ in terms of the page loading process and the extent of interaction between a user and the server.

Server-side rendering (SSR) 

SSR is an approach where the server handles most of the heavy lifting. Upon a user’s request, the server generates the necessary dynamic content, assembles an HTML page, and sends it fully formed to the user.

This method ensures compatibility across all browsers and is particularly effective for content-heavy sites that require less frequent updates, such as digital newspapers or informational blogs. However, the process can be slower because each page request necessitates a round trip to the server, which processes and returns the complete page.

Client-side Rendering (CSR)

Contrastingly, CSR operates by sending a skeletal HTML page to the user’s browser on the initial request. The dynamic content of the page is then rendered directly in the browser using JavaScript. This method excludes the server from page rendering, significantly speeding up the process and reducing server load.

CSR is especially suited for interactive applications where user experiences are dynamic and the content changes frequently, such as social media platforms or e-commerce sites. However, its reliance on JavaScript means that users with JavaScript-disabled or unsupported browsers might not experience the site as intended.

Each of these architectural choices has its advantages and challenges, making them suitable for different types of web applications based on their specific needs and the expected user interactions. By selecting the appropriate rendering method, developers can optimize both performance and user experience in their PWAs.

Best Progressive Web Apps Examples

At the beginning of this article, we have provided you with the key features and benefits of Progressive Web Applications. Yet, to have a better understanding of how PWA improves the overall performance of a platform, you should take a closer look at the specific Progressive Web Application examples that achieved immense success.

X (previously Twitter)

Perhaps one of the most prominent examples of a PWA platform is Twitter, and to be even more specific, Twitter Lite. The PWA version of the website supports offline usage, as it retrieves the information of the visited web page from the cache. 

Launching Twitter Lite on the market resulted in a 65% increase in pages per session, a 75% increase in tweets sent, and a 20% decrease in bounce rate. Nicolas Gallagher, an Engineering Lead for Twitter Lite, said “Twitter Lite is now the fastest, least expensive, and most reliable way to use Twitter. The web app rivals the performance of our native apps but requires less than 3% of the device storage space compared to Twitter for Android.”

AliExpress

AliExpress is an e-commerce platform used to sell products internationally. Due to the variety of goods and their competitive prices, AliExpress has about 150 million active customers worldwide. Hence, a PWA version of the marketplace was developed to ensure the best mobile experience for all those users. 

This step increased the number of new visitors by 104% and the amount of time spent in the online store by 74%. In addition, the number of pages visited by one user during a single session doubled across all browsers. These stats once again show how immense is the impact of PWA technology.

Forbes

A global media company focusing on business, investing, technology, entrepreneurship, leadership, and lifestyle, has also embraced PWA technology to revamp its mobile experience. The Forbes PWA aims to significantly improve loading times and user engagement, particularly for mobile users who access content on the go.

In their case, the PWA implementation led to a dramatic increase in user sessions, with a reported 100% increase in engagement due to the faster loading times and an offline reading mode, which allows users to access content even without an internet connection.

LV BET

One of the fastest-growing brands in the sports betting industry decided to step up its efforts and create a PWA app. The technology allows LV BET customers to bet anywhere and anytime using such features as a match tracker, fast deposits and payouts, cash-out options, prematch and live bets, as well as virtual sports betting.

What is important in a sports betting app development is a high performance determined by the huge amount of data that needs to be processed. This includes live odds, rates and wagers calculations, and statistics in relation to multiple sports simultaneously. The security of sensitive data, such as payment details, credit cards, and personal information is a critical requirement for such a platform as well. LV BET’s PWA app meets both of these criteria.

CasinoSinners

Although Casino Sinners is quite a novice in the iGaming industry, it has already gained many fans. It is partially due to the launching of a new application based on PWA that increased speed and security – the two vital elements that an online casino app requires.

Casino Sinners boasts about using PWA technology, claiming that users can play whenever they want without glitches and delays in loading time, irrespective of device and browser.

Fantom Wallet

An e-wallet for the Fantom public mainnet that enables its users to store and transfer FTM cryptocurrency between accounts also took steps to enhance the comfort of its users by developing a PWA app. 

Secure transactions, easy access to the wallet from the home screen, and the storage of relevant data in the case of repeated visits are the factors that positively influence the User’s Experience and make PWA technology a proper solution for FinTech services development as well.

Starbucks

The coffeehouse chain launched its PWA to offer customers a seamless ordering experience, whether online or offline, mimicking the high functionality of its native app. The Starbucks PWA allows users to browse the menu, customize their orders, and add items to their cart, all without an internet connection.

Once online, users can view the location of nearby stores and place their orders. Starbucks reported that the PWA is twice as fast as their previous mobile website, leading to increased user engagement and sales conversions.

Progressive Web Apps vs Native Apps

What should I choose, PWA or custom mobile app development? – It’s one of the most frequently asked questions, and we agree that it’s always a tough decision, but it’s crucial from your product’s perspective. To make it easier for you, we resolved the Progressive Web Apps vs native battle in our other article.

PWAs in Official Marketplaces

Although Progressive Web Applications are installable, most customers don’t have a clue that such a feature is available in the first place. From a marketing point of view, it is a serious drawback. Fortunately, there is a way to publish the app in the official marketplaces.

Google Play

In 2019 Google announced a new concept – Trusted Web Activity. TWA gives developers the possibility to publish web content in the Google Play store. TWA wraps the PWA application into an Android container (activity) and displays a full-screen Chrome browser inside of an Android app without browser UI elements, like a well-known URL bar.

TWA gives you one more feature – transitions between the web and native content are between activities, so it lets you create an app that uses PWA features only for selected views. The whole process of creating a TWA application is clearly described in the official Google docs.

What needs to be clarified here is what ‘trusted’ means in the context of TWA. Google decided to introduce a restriction under which you must confirm that you are an owner of the website you want to pack into TWA. You can prove this by setting up Digital Asset Links. Luckily enough, it’s nothing hard – you just need to upload to your server a file that points to your app as well as some data from your app that points to your website.

App Store

In the case of Apple devices, it’s not so straightforward. In general, Apple’s review process is much more strict. But still, app store optimization is possible. All you have to do is wrap your PWA app into WebView using Cordova, PWA Builder, or other similar solutions. It’s important to note here that officially there is a rule in the Apple Store Review Guidelines (4.2) that gives them the right to reject your submission.

“Your app should include features, content, and UI that elevate it beyond a repackaged website. If your app is not particularly useful, unique, or “app-like,” it doesn’t belong on the App Store.”

Nevertheless, there is a lot of stuff in the Apple App Store that could be affected by this clause, but they are still there. I assume that Apple will be a bit more restrictive when reviewing apps’ potential updates.

Microsoft Store

Microsoft informs about this new feature in their docs. The company also prepared an official tool to transform your PWA app into a native counterpart – PWA Builder. They even listed the advantages of such a move in the files section, including:

• discoverability,
• trustworthiness,
• easy install,
• business insights.

In the case of the Microsoft Store, the PWA application runs in a lightweight native app wrapper independent of the Microsoft Edge browser window.

Huawei AppGallery

As for Huawei’s official store, there is an opportunity to turn a PWA application into a so-called Quick App and upload it to the Quick Apps section of AppGallery. You can find step-by-step instructions on their official website. Once you have submitted the request to upload your PWA app to Quick Apps, you have to wait for the review.

Just like Microsoft, Huawei notices the benefits of PWA and enumerates them. At the same time, Huawei mentions the possibility of adding a Quick Apps Center as well as the icons of particular Quick Apps to the home screen.

The State of PWA

Summing it all up, Progressive Web Applications merge the best features of web and mobile capabilities, offering an optimal solution for companies looking to enhance their digital presence. The technology provides the accessibility of the web alongside the rich functionality and superior performance of native applications. 

PWAs are widely regarded as a straightforward entry point into the mobile realm, thanks to their cross-platform compatibility and ease of deployment. For businesses considering this approach, consulting with a specialized PWA development company like CrustLab can be a wise move. We’ll help you tailor a PWA strategy that aligns with your specific business objectives, ensuring a smooth and effective implementation.