- Mobile
- Android
- Healthcare
- Privacy
A private health-record tracker for Android
An app for keeping blood pressure, weight, sugar, medication and symptom records on the phone, with privacy checks built into the tests.
- Industry
- Personal health
- Our role
- Design and development
- Stack
- React NativeExpoTypeScriptSQLitei18nextGitHub Actions
The challenge
People who track their health want a simple log they control. Health data is sensitive, so the app had to keep records on the device, be honest about what it does and does not protect, and make sure no health value could ever leak into advertising or analytics.
Screens
Illustrative screens redrawn from the app's design mockups. Demo data only.
What we built
Many record types
Blood pressure, weight, blood sugar, heart rate, temperature, height, medication, symptoms and free-form notes.
Timeline and trends
A searchable timeline with filters, plus trend charts for each measurement.
Documents and exports
Attach reports and images, export to PDF or CSV, and back up and restore.
App lock
A PIN stored only as a salted hash, with optional biometric unlock.
Three languages
English, Spanish and Hindi.
Privacy guarded by tests
Automated tests fail the build if a health value reaches an advertising request, analytics or crash reports.
Engineering decisions
- The advertising code is isolated: it takes no data, and tests check that it cannot import anything that reads health records.
- A wording test blocks claims the app cannot back up, and the in-app privacy text states plainly what is and is not encrypted.
- Records stay in a local database, and Android's own app-backup is switched off.
- A continuous-integration workflow runs the type check, linting, tests and a bundle check on every push.
The result
A private, local-first health log whose privacy promises are checked by tests. It is built, with release steps and device checks still pending, and it is not described here as published.
Built by our lead developer as our own product.