Kintsugi — a private wellbeing and recovery companion

Kintsugi is a wellbeing and productivity app for the unglamorous work of putting things back together. It takes recovery, ADHD, mood, grief, learning and everyday admin — the things people usually juggle across five apps that know nothing about each other — and holds them in one place, so the craving tool and the planner are part of the same day rather than separate errands.

Visit: kintsugiwellbeing.com

The challenge

Build something genuinely useful on a bad day, not just a good one — and do it while handling special-category health data to a standard that stands up to scrutiny. Two constraints shaped everything: nothing that helps someone in difficulty may sit behind a paywall, and the counter does not reset to zero because someone had a hard week.

What we built

• Planner, journal, calendar and routines for the ordinary run of a day
• Recovery tooling — a sober journey that counts forward rather than punishing a lapse, plus crisis routes that are always one tap away
• Bodyweight training from first-week beginner upwards, every movement with an easier version
• Food and diet logging with the numbers off by default and switched on only if wanted
• Insights that build a picture quietly over months, without asking anyone to score themselves daily
• A find-help directory for the moment someone needs a person rather than an app

Handling special-category data

Health data is Article 9 data under UK GDPR, so the privacy work is architecture rather than policy. Access decisions are audited — grants and denials, because a denial that leaves no trace cannot be reviewed. Erasure is a soft-delete followed by an audited hard-delete, so a deletion request is evidenced rather than asserted. Data minimisation is a design constraint applied before a field is added, not a clean-up afterwards. The application is hosted in Frankfurt so the data stays in the EU.

There are no adverts and no tracking. That is a product decision with an engineering consequence: there is no analytics pipeline quietly accumulating behavioural data about people at their most vulnerable.

Technology stack

• Backend: Node.js, Express, Knex migrations, Socket.IO for live updates
• Database: PostgreSQL 18
• Auth: Firebase Authentication with server-side verification
• Validation and hardening: Zod schemas, Helmet, rate limiting on every public route
• Clients: responsive web app plus iOS and Android
• Hosting: Render, Frankfurt region — EU data residency by placement, not by promise
• CI/CD: Bitbucket with deploy on commit

Screens from the project