How the builder actually works
The mechanics are three moves. Pick a design from the birthday library, and the page takes its shape โ headings, colours, the rhythm down a phone screen. Fill the details block, which wants the date, times, venue, and the one or two notes guests would otherwise text to ask. Switch on replies, and the builder separates itself from a poster maker: every guest who confirms lands in a live list under their own name.
Nothing is locked in. Swap the design halfway through and the details carry over. Leave a section empty and it simply does not appear on the page, so a half-built invitation looks deliberate instead of unfinished.