What is Progressive Web Apps (PWA)?

Estimated Reading Time 4 minutes

Quick Answer:

A progressive web application (PWA) is a hybrid internet revolution. This new web technology enhances UX giving the user more opportunity. This innovation was created by taking the best bits of a native app and web app, in essence creating the best of both worlds.


Skip to Pros and Cons

Technical answer:

For a PWA to work there a two elements which are needed, The Service Worker and The Web App Manifest.

  • The Service Worker is vital to allow a PWA to function offline. What it is, is a JavaScript background task that replaces the traditional web cache by using a cache API. The cache API wakes up when needed, listening to different network requests saving the static resources from the visited sites. The Service Worker saves these resources by redirecting the web page from going to the server but instead go to The Service Worker.
  • The second element which a PWA needs is the Web App Manifest, this is a JSON script, making it possible for the Web App to have a home screen icon, theme, splash screen and the ability for the web app to run in full-screen mode and as a standalone application.

PWA’s can be viewed as a set of web pages or a single web page that are rendered on a mobile device browser. They use common web languages such as HTML, HTML5, CSS, etc which simulate the retrieval of data from a mock API, all in a shell like architecture. To give the application it’s native appearance, a the Web App Manifest is used to describe the application and the Service Worker is used similar to the cache.

A common analogy for how a PWA works is related to the M&M peanut simulating a self-contained unit.

PWA Analogy

Peanut= The core Web HTML page content

Chocolate= The Web App Manifest applying the JSON script

Hard Candy Shell= Javascript which redirects the web page from retrieving the page from the server to the Service Worker

Pros and Cons of PWA’s:


  • No ‘installation required’.
  • No application update required.
  • Offline use.
  • Quick loading.
  • Home screen icon.
  • Fresh content always available.
  • Secure.
  • Responsive.
  • Less intrusive.
  • Less storage used.
  • Linkable.
  • Shareable.
  • Indexable.


  • Not all browsers are supported.
  • Not all native device software functionality is supported.
  • Not all native device hardware functionality is supported.
  • There is no central download store.
  • Cross app logins are not supported.

There are many reasons why you should think about using Progressive Web Apps. Not only are they killer hot for user experience, they are also cheaper to create than an actual app.

You really do get the best of both worlds with these. Lastly, due to PWA’s being more reliable and quicker to load we do need to say goodbye to the Down-asaurus, as he will never appear with a PWA.

RIP Dino.



Jenny Farnfield
Jenny Farnfield graduated from Southampton Solent University with a 2:1 Degree in Advertising, and brings extensive commercial, digital and marketing acumen to the team at Digital Clarity. Jenny has been recognised by both UK Search Awards and the Ecommerce Awards. Jenny is also IDM certified, and utilises a rigorous, granular approach to digital marketing. With over 6 years’ experience, Jenny digs deep to find solutions and uses an immersive approach in her accounts, turning numbers and data into actionable solutions for her clients.