How are mechanical keyboards different from "regular" keyboards?

Most people simply use whatever keyboard is provided at work, or some cheap best seller from Amazon. These keyboards use rubber dome technology, where there's a special rubber layer under the keycaps (the small squares with letters) and when pressed all the way down the rubber contacts close the circuit and send a keypress. Generally, it's impossible to move around keys, and also impossible to change the value of any key. The feeling of these keyboards is slightly mushy, and generally they are fairly quiet. They are also hard to modify.

Mechanical keyboards are a completely different story. Every single component is customizable. At first, this may seem daunting, but ultimately this allows you to create a keyboard uniquely tailored to your style and preferences.

Switches

Let's start with the most variable option out there: key switches. A mechanical keyboard fundamentally works differently from a rubber dome
keyboard. Rather than having one giant rubber layer, a mechanical keyboard is composed of individual keyswitches. A keyswitch looks like this:

As you can see, there is a colored stem and then the main body. Inside of it, there is a spring with a little metal contact that closes the connection when the key is pressed.

There are many different types of switches. This page shows some animated diagrams with differences. The key takeway is that there are options on how "clicky" you want the switch and how "heavy". The most common switch is a "Cherry Brown", which is moderately clicky and has a medium spring resistance. For purposes of brevity, we won't go into more detail. Please google around for Cherry Blue, Cherry Red, and Cherry Black for other common choices.

Keycaps

This is the really fun part - no one knows what switches you have until you start typing, but EVERYONE will get a chance to enjoy your keycaps. These come in all sorts of shapes, sizes, materials, and colors.

You can see some more examples at the following sites:

People go really wild with these and truly express their creativity and identity. You can see some popular community choices at r/mechanicalkeyboards.

Form Factors and Cases

Mechanical keyboards come in all sorts of shapes, sizes, and configurations. There are ortholinear, staggered, 60%, 40%, and so on. Depending on your needs, and the software that you will run on the keyboard, different sizes will stand out the most.

Please see the following links for some great guides on this topic:

You can find more information about general keyboard terminology and additional background information at the following links: