What's a realistic timeline?
A single-feature web app: 3–5 days. Auth, database and payments: 2 weeks. Multi-tenant SaaS with admin panel and billing tiers: 4–6 weeks. We've shipped at every band — most clients land in the 2-week zone.
What quietly adds weeks?
Custom design (not using a system), bespoke email templates, role hierarchies beyond user/admin, white-label theming, and any integration with a system that doesn't have an API. Each one is 'just a few days' that becomes two weeks.
What can be skipped for v1?
Onboarding flows beyond one screen, in-app notifications, exports beyond CSV, audit logs, SSO, and the marketing site. Every one of these is a v2 problem dressed as a v1 must-have.
Why most agencies quote 3–6 months
Because they staff 4–8 people who all need coordinating. Two senior builders with AI tooling cover the same scope in a fifth of the time — that's the whole point of a vibe-coded studio.