Updone: keeping a marketplace's money where it belongs.

Updone connects event hosts with vetted hospitality staff: bartenders, cocktail servers, waiters, event helpers. Once a client and a bartender start talking, the natural next move is "here's my number, let's sort it on WhatsApp." Every time that happens, the platform loses the booking fee, and both sides lose the protection: vetting, payment security, recourse if someone no-shows.

So the brief was really two briefs. Make chat good enough that people want to stay in it. And make leaving it genuinely harder, without treating users like suspects.

Guardrails fail in two directions. Too soft and the leak continues. Too hard and legitimate conversations break: an address for the venue looks a lot like an address for a meetup. Seven iterations of the chat flow were mostly about tuning this dose.

A working reconstruction of the guardrail logic. Type a normal message and it sends clean. Try slipping in a phone number, an email, or "WhatsApp me": watch how the system responds. This is the warn-first pattern from decision one.

Pattern-matching numbers is the easy layer. The design work was the full path: what the sender sees, what the receiver sees, how a message is held for review, when a repeat attempt escalates from a warning to a temporary chat hold, and how a false positive gets appealed without a support ticket.

The updated guardrails shipped as a coordinated release across both apps.