Will custom fonts slow down my Shopify store?

Custom fonts have a cost but it's manageable. Each font file and weight you load adds weight and can cause layout shift or a flash if handled poorly. Keep it to the one or two weights you actually use, self-host or use Shopify's font system, preload the primary font, and set font-display so text stays visible while the font loads.

The two mistakes that hurt: loading a whole family when you use two weights, and not reserving space, which causes CLS. Done right, a brand font costs a few tens of milliseconds — well worth it for identity.