CareQuest

CareQuest is a care-logging PWA for family caregivers. The product goal is simple — capture a care session in under 10 seconds with no typing and no sign-up — and the interesting part is the engineering that makes “no account required” a real default rather than a marketing line.

It’s live at veai.jp/carequest and open source.

Design constraint: local-first, cloud-optional

Every record is written to the browser’s localStorage first. Core features — logging, the weekly look-back, JSON/CSV export, deletion — all work with no network and no account. Cloud sync exists, but it is strictly opt-in: signing in via Amazon Cognito is what unlocks cross-device restore, and it is never on the critical path for using the app.

This constraint drives most of the architecture. The front end is a static export that runs entirely client-side; the serverless back end only ever sees data from users who have explicitly signed in.

Architecture

Browser (PWA / localStorage)
  │
  ├─ Next.js 16 (static export, basePath: /carequest)
  │     └─ TypeScript 5 · React 19 · Tailwind CSS 4
  │
  ├─ Service Worker  (offline support; git-SHA version injected at build)
  │
  └─ AWS CloudFront ── S3
          │
          └─ [opt-in, sign-in only]
               API Gateway ── Lambda ── DynamoDB
               Amazon Cognito (user pool auth)

The static site ships from S3 behind CloudFront. The service worker gives offline support and pins a build version by injecting the git SHA at build time, so a stale cache is diagnosable in the field. Signed-in traffic flows through API Gateway (Cognito authorizer) into a Lambda + DynamoDB path for sync.

Infrastructure as Code

The entire back end is provisioned with AWS CDK v2 (infra/) — nothing is clicked together in the console. A cdk synth produces:

• Amazon Cognito user pool for authentication
• DynamoDB table with point-in-time recovery enabled
• API Gateway with a Cognito authorizer and throttling (10 rps, burst 20)
• Lambda for the sync API
• 2× CloudWatch alarms and an AWS Budget ($10/mo) — cost and health guardrails baked into the stack

Tech stack

Layer	Choice
Framework	Next.js 16 (static export)
Language	TypeScript 5, React 19
Styling	Tailwind CSS 4
Auth / sync	Amazon Cognito + aws-amplify v6
IaC	AWS CDK v2
Unit tests	Vitest 4
E2E tests	Playwright
CI	GitHub Actions

Notable details

• Privacy by default. With no account, records never leave the device. The community “Candlelight” widget — a live count of how many caregivers logged today — is served from aggregated, anonymized data only; no individual record is ever exposed.
• Data portability. Users can export everything as JSON/CSV, and account/cloud deletion is self-serve from within the app.
• Tested and shipped. Vitest unit tests and Playwright E2E run in GitHub Actions; the same pipeline deploys the static export to S3/CloudFront.

Curious about the code? The repository is public: github.com/larai-w/carequest.