ADR 0001: Technology Stack and Container Architecture Selection

Status: Accepted
Date: 2026-10-10
Deciders: Core Engineering Team & AI Orchestrator

Context

The Personal Lifecycle Tracker requires high availability, zero host runtime coupling, deterministic API synchronization, and multi-tenant data persistence across dev and prod environments.

Decision

1. Adopt FastAPI (Python 3.11) with Pydantic v2 and SQLAlchemy for backend services.
2. Adopt React 19 + TypeScript + Vite 8 + Tailwind CSS for frontend.
3. Freeze OpenAPI 3.0.3 specification in contracts/openapi.yaml prior to backend implementation.
4. Orchestrate all local dependencies via Docker Compose with healthchecks.
5. Deploy production gateway via Caddy 2 reverse proxy.
6. Provide dual cloud implementations across Render (PaaS) and AWS (EC2 Compose + Serverless).

Consequences

• Full environment parity between local development and cloud deployments.
• Zero host tool dependency requirements.
• Strong compile-time and runtime type safety across tiers.