The "custom" attribute of websites has started to be a subject of debate, since the best website builders offer very good customization possibilities, both in the builder interface and through coding.
In this article we will use the term "custom" only to refer to websites created by programmers who code the entire site and do not use any website builder.
When we say "site builders" we mean Shopify, Wix, Editor X, Wordpress, Squarespace, etc.

Custom vs Web Builder
Custom website characteristics:
highest level of customization
functionality options are practically unlimited
possibility of implementing state of the art security systems, if the budget allows
control over the performance of the servers that host the website
if you have really unusual needs, the custom website can be tailored to them
high cost, compared to website builders
frequent maintenance needed
long construction times