monk-code-screen/README.md

monk-code-screen

Billing/subscriptions/invoicing backend skeleton. Bun + Hono + bun:sqlite (zero network deps at runtime; TS runs natively, no build step).

⚡ START COMMAND (sticky)

bun run dev          # http://localhost:3000, hot reload

Other commands:

bun run start        # no watch
bun run db:reset     # wipe data.db and reseed
bunx tsc --noEmit    # typecheck

Layout

src/index.ts    Hono app + routes
src/db.ts       opens data.db, applies schema, seeds if empty (runs on import)
src/schema.sql  customers / plans / subscriptions / invoices (idempotent)

DB is data.db at repo root (WAL, FK on). Boot always re-applies schema, so adding a table = edit schema.sql + restart.

Routes

curl localhost:3000/health
curl localhost:3000/customers
curl localhost:3000/customers/cus_ada/invoices
curl -X POST localhost:3000/subscriptions \
  -H 'content-type: application/json' \
  -d '{"customer_id":"cus_grace","plan_id":"plan_basic"}'

POST /subscriptions is the happy path: validates with zod, creates subscription + first invoice in one transaction, returns both (201).

Seed data

• customers: cus_ada, cus_grace
• plans: plan_basic ($10/mo), plan_pro ($50/mo)
• cus_ada has an active sub_1 on pro with open inv_1

Extension cheatsheet (interview)

• New route: add to src/index.ts, db.query(...).all()/get(), db.run(sql, [params])
• Multi-write: db.transaction(() => { ... })()
• Validation: z.object({...}).safeParse(await c.req.json())
• New table: append CREATE TABLE IF NOT EXISTS to schema.sql, restart (or db:reset if changing existing tables)