Keycap profile is the shape of the cap — its height, the curve of the top surface, and how it slopes from row to row. Most beginners ignore profile entirely and pick caps for the colour. Then they switch to a different profile and discover that typing feels completely different on the same keyboard.
OEM
OEM is the default profile on most pre-built keyboards. The caps are tall, sloped from row to row, and have a slight cylindrical dish on the top. It is the profile most people have typed on for years without thinking about it. Comfortable, neutral, no surprises.
Cherry
Cherry profile is similar to OEM but slightly shorter overall and with a more pronounced sculpting between rows. Most enthusiasts consider it the most comfortable profile for long typing — the hands rest naturally because the rows curve to match finger length. If you can only try one upgrade from OEM, this is it.
SA
SA profile is tall, dramatically sculpted, and has a spherical (round) dish on each cap rather than cylindrical. It looks distinctive and produces a deeper, more resonant typing sound. Some people love the feel; others find the height tiring on long sessions. Try before committing — SA divides opinion.
DSA and XDA
DSA and XDA are uniform profiles — every row is the same height, with a flat or slightly curved top. They look very modern and clean. The downside is that without row-by-row sculpting, your fingers have to reach the same distance for every row, which some find less comfortable for long typing. They are popular for compact boards because the uniform rows make compact key combinations easier to read.
How much it matters
If you type for several hours a day, the profile is probably the second-biggest factor (after switches) in how the keyboard feels. If you type for half an hour a day, you probably will not notice the difference between OEM and Cherry. Be honest about your usage before spending serious money on a custom keycap set.
A complete custom keycap set costs anywhere from forty to four hundred euros. Doubleshot ABS keycaps (the cheaper end) wear faster than thick PBT (the better end), but ABS often produces a slightly nicer typing sound. There are reasons for both.