Sequel to yesterday's post about domains, I'll be writing about subdomains today as promised, a lot of people may feel that subdomains are totally unnecessary seeing as a domain can accommodate virtually everything that a subdomain has to offer; these people are partly right, however, subdomains were extremely useful in the past and are still useful today (if you know exactly why you're using it). Now to subdomains, there are times when an entity needs to have a complimentary service or bespoke service but they want it tied to their main domain (think website), they register a subdomain, it's kind of like extending your house by purchasing your neighbour's house. It was especially convenient for making websites that are tailored to mobile devices in the past.
SUBDOMAINS WERE INVALUABLE IN THE PAST
Having subdomains made it easier to separate concerns such that a team can work on a domain/subdomain that's tailored to a particular platform without getting in the way of the other teams that work on other subdomains. People tend to agree that the smaller a team is, the faster it can move and in tech, speed is a big deal. With the advent of SEO (search engine optimization) and improvements on the capabilities of programming languages, the uses of subdomains have been somewhat reduced, this doesn't in any way mean that it isn't useful, I'll be giving two brilliant uses of subdomains in a bid to capture why they're still relevant.
SUBDOMAIN USECASES
Let's assume you own a web platform that works really great and you suddenly need to add an e-commerce arm to the business. The old platform wasn't really built with extension in mind as such you've been told that if you want to add new features you need to tear down the entire thing and rebuild. You on the other hand subscribe to the "if it isn't broken, don't fix it" ideology. Subdomains provide an easy way out as you can build a standalone e-commerce platform and make it a subdomain of the main platform such that they're still linked in a way. Software engineers use subdomains a lot in projects and you'll see why in a bit. Say for example Hashnode, it's a huge platform used by a lot of people, the platform has to be dependable as such the developers need to be sure that their updates work properly before updating the Hashnode platform. Normally we have some extensions (think software) that help us simulate how our application will run, however, simulations aren't always right on the mark.
FINALLY...
There are times when it's important to have real people use the application for a bit in order to be able to ascertain that the platform works perfectly and users won't have so many problems with it. Subdomains are extra useful here as one can use the subdomain as a playground where future updates are tried and tested before updating the main platform. It is important to note that subdomains are not SEO-friendly as the web crawlers (that literally searches every web resource on the internet and indexes it) perceives subdomains as a standalone platform and this can hurt the rating of the subdomain as it wasn't built to standalone or be assessed as a standalone platform.