1. Architecture chosen
Manager pushes environment variables into every business's .env, rather than businesses fetching config at runtime. Manager has no database of its own today (confirmed via code — no Prisma, no ORM dependency anywhere in manager/); every piece of its state is either an env var or a flat file under STACKS_DIR. A "runtime shared-config source" design would make every single email send (including OTP login) depend on Manager being reachable — a new failure mode this app has never had, for no real benefit. Instead:
Storage: one JSON file, stacks/manager/global-settings.json (gitignored), shaped for future sections (SMS, storage, backups, branding...) to slot in as sibling keys.
Secret at rest: the SMTP password is AES-256-GCM encrypted with a new MANAGER_SETTINGS_ENCRYPTION_KEY, never returned to the browser.
Rollout: saving complete settings automatically pushes the 7 EMAIL_* keys into every business's .env via the exact same surgical upsertEnvValues helper updateBusiness() already uses for name/domain edits, then force-recreates each container (composeUp(dir, {forceRecreate:true})) — the identical mechanism that already applies domain changes today.
New businesses get the current global settings baked into their .env at provisioning time — no manual step, ever.
2. Files changed
New (Manager): global-settings.ts (storage+encryption), email-rollout.ts (push-to-all-businesses), test-email.ts (standalone nodemailer test-send), dashboard/settings/ (page.tsx, actions.ts, email-settings-form.tsx).
Modified (Manager): compose-template.ts (optional email block in generated .env), provisioning.ts (reads global settings at creation), dashboard/layout.tsx (Settings nav link), package.json/package-lock.json (added nodemailer).
Modified (main app): brevo-email-provider.ts (added encryption mode + replyTo, backward-compatible), its test file (8 new tests).
Modified (docs): root .gitignore, .env.example, .env.business.example, manager/.env.example.
3. New volumes/databases/config files
None — no new Docker volume, no database. One new gitignored file, stacks/manager/global-settings.json, living inside the STACKS_DIR bind-mount Manager already has.
4. New environment variables
MANAGER_SETTINGS_ENCRYPTION_KEY (Manager only, required to use Settings) — 32-byte hex, generate with openssl rand -hex 32.
EMAIL_SMTP_ENCRYPTION and EMAIL_REPLY_TO (main app, both optional) — unset EMAIL_SMTP_ENCRYPTION preserves today's exact port-based inference, so existing deployments are unaffected.
Reply-to is now business-specific with global fallback,
5. How settings are persisted
stacks/manager/global-settings.json, written by saveEmailSettings(). The password is encrypted before writing; every other field is plain text (host, port, username, from-address, from-name, reply-to, encryption mode, last-test result) since none of those are secrets.
6. How business containers receive global settings
Via their own .env file (Docker Compose's env_file:, unchanged mechanism) — Manager writes the 7 EMAIL_* keys into it and recreates the container. Nothing in the business app itself needed a new runtime dependency; getEmailProvider() still just reads process.env once at process start, exactly as before.
7. What happens to existing businesses when settings change
Saving complete settings (host+username+password+from-address all present) automatically loops every business, updates its .env, and force-recreates its container in one action — the UI reports "applied to N of M businesses" with per-business failure reasons. A separate "Reapply to all businesses" button retries this without re-entering anything, for recovering from a business that was down during the last save. Saving incomplete settings persists them as a draft and touches no business (verified live — this is what stops a business from being flipped into a broken "brevo with blank credentials" state).
8. Manual deployment/update steps on the VPS
Generate a key: openssl rand -hex 32, add it as MANAGER_SETTINGS_ENCRYPTION_KEY to stacks/manager/.env.
Rebuild/redeploy the Manager image and the main app image (both changed) as usual.
Open Manager → Settings, fill in real SMTP details, send a test email, then Save — this rolls out to every existing business automatically. Nothing else needs to run by hand.
9. Security considerations
Password never logged, never returned to the browser after save (only a hasPassword boolean) — confirmed live: the form re-shows a masked placeholder, not the real value.
Test-email errors are categorized (auth/connection/timeout) before display — the raw SMTP error is never forwarded.
Encrypted at rest with AES-256-GCM; losing/rotating the key makes the stored password undecryptable (documented in manager/.env.example).
Settings routes sit under manager/src/proxy.ts's existing auth gate — no new auth surface.
Validated before rollout: malformed addresses/ports are rejected before Save, and rollout only fires when configuration is actually complete.
On JSON vs. database for Manager: JSON is the right call here. Reasoning:
Manager has zero DB dependencies today, deliberately — its own package.json description says an earlier attempt at giving it business-data access "repeatedly broke." Introducing SQLite/Prisma just for one settings blob breaks that design principle for not much gain.
The access pattern is a poor fit for a DB anyway: read on page-load/provisioning/rollout, written by a human clicking Save occasionally. No queries, no joins, no need for transactions beyond "read-modify-write one small file."
Reconsider if: multiple admins need to edit concurrently with conflict detection, you want an audit history of who-changed-what-when beyond "last test result," or the settings graph grows relational (e.g., per-business overrides tied by foreign key to businesses) rather than a flat global blob. None of that applies yet.
NextChair
Booking app as an alternative to Booksy
VPS deployment (multi-business)
One-time setup on a fresh VPS with Docker and the Compose plugin already installed. Run everything from the repo's checkout directory.
# 1. Clone the repo at the path you intend to keep it at — STACKS_DIR
# below must be this exact absolute path, since containers shell
# `docker compose` back out to the HOST's dockerd via a mounted
# socket (see stacks/infra/compose.yaml and manager/README.md for why).
git clone <your-repo-url> /opt/nextchair
cd /opt/nextchair
# 2. Shared Docker network every stack attaches to.
docker network create next-chair-edge
# 3. Shared infrastructure: MySQL, Caddy (reverse proxy + automatic TLS),
# Dockge (stack management UI, http://<vps-ip>:5001).
cp .env.infra.example stacks/infra/.env
# edit stacks/infra/.env — MYSQL_ROOT_PASSWORD, ACME_EMAIL, and set
# STACKS_DIR to this exact clone path, e.g. /opt/nextchair/stacks
docker compose -f stacks/infra/compose.yaml --env-file stacks/infra/.env up -d
# 4. Build the shared business image (re-run this after every code
# update — see stacks/blake-heritage/compose.yaml's own note).
docker build -t nextchair-app:latest .
# 5. The management UI (manager/) — this is what you'll use to add
# businesses from here on, not the by-hand steps in stacks/infra/
# compose.yaml's header (those exist only as a fallback/reference).
cp manager/.env.example stacks/manager/.env
# edit stacks/manager/.env — MANAGER_EMAIL/PASSWORD_HASH, MANAGER_SESSION_SECRET,
# MYSQL_ROOT_PASSWORD (same value as step 3), and STACKS_DIR (same as step 3)
docker compose -f stacks/manager/compose.yaml --env-file stacks/manager/.env up -d --build
Then, per business, point its domain's DNS at the VPS and use the
management UI (https://<your-manager-domain> — add a Caddy site for it
the same way as any business, see stacks/infra/sites/.gitkeep) to add
it: name, slug, domain — it creates the database, generates secrets,
starts the container, and runs migrations for you. Finish setup by
visiting https://<business-domain>/install.
To ship a code update to every business: git pull, rebuild the image
(step 4), then use each business's Update button in the management UI
(or docker compose up -d --force-recreate in its stacks/<slug>/
directory) to recreate it against the new image.