> ## Documentation Index
> Fetch the complete documentation index at: https://docs.findmydata.io/llms.txt
> Use this file to discover all available pages before exploring further.

# ADR 0001 runtime language repo layout

# ADR-0001: Runtime, language, and repository layout

**Status:** Accepted · 2026-07-14

## Decision

* **TypeScript everywhere** (server, worker, web, shared contracts).
* **Bun 1.3.x** as the runtime and toolchain: TS-native execution, built-in
  `bun:sqlite`, built-in Jest-compatible test runner, workspace-aware installs.
* **Hono** for the HTTP API (TS-first, tiny, runs natively on Bun and Node).
* **Zod** for runtime validation of API inputs, config, events, and AI outputs.
* **React + Vite** for the web app.
* **Bun workspaces monorepo:**
  * `packages/shared` — types, contracts, event schemas shared by server and web
  * `packages/server` — API + worker + domain modules + migrations + fixtures + tests
  * `packages/web` — React UI

## Context

The dev machine has no Node.js; Bun 1.3.14 is installed. Bun removes two classic
sources of setup friction for a credential-free vertical slice: native-module
compilation for SQLite drivers and a separate test-runner/transpiler toolchain.
One language across API/worker/UI maximizes velocity for a single-session build and
keeps contracts shared, not duplicated.

## Consequences

* Local development requires Bun (`curl -fsSL https://bun.sh/install | bash`); the
  README states the exact version tested.
* Production evolution path: the server code uses web-standard APIs via Hono and a
  thin DB layer, so migrating to Node 22 + `better-sqlite3`/Postgres is mechanical
  if a customer environment mandates Node. Revisit if Azure deployment tooling
  (e.g., Functions) forces a Node runtime.
* No Python/JVM ML stack in the slice; the inference ensemble is TS + provider
  adapters (see ADR-0005), which matches the mock-first requirement.