Fonts for SaaS products

SaaS interfaces are read small and read constantly — labels, tables, tooltips, dense forms — so the body face has to be a legibility specialist first. Inter, IBM Plex Sans and their peers exist for exactly this: tall x-heights, even color, and disambiguated glyphs so a lowercase l never reads as a 1 in a settings field. The heading face can carry a little product personality in nav, empty states and marketing surfaces, but keep the contrast modest so the app feels like one coherent system. Check that the family offers 400, 500 and 600 at least, because interface hierarchy is built almost entirely from weight, not size. If your product shows code, keys or IDs, budget for a mono too — a monospaced face with clear zeros keeps configuration values honest and copy-pasteable.