| name | cmux-billing |
| description | Stripe checkout, pricing, subscription, Pro plan, webhook, and entitlement runbook for cmux billing work. Use when editing or debugging billing, pricing, Stripe Checkout, subscription recording, Pro plan status, webhooks, entitlement metadata, or pricing dev/prod tooling. |
cmux Billing
Use this skill before changing billing, pricing, Stripe, Pro entitlement, checkout, webhook, or subscription code.
Architecture Map
/api/billing/checkout creates Stripe Checkout Sessions for Pro when STRIPE_SECRET_KEY is set. It sets client_reference_id to the Stack user id, auto-creates an anonymous Stack user for signed-out buyers, and falls back to the legacy Stack purchase path when Stripe is unset or plan=team./api/billing/portal resolves the current Stack user, looks up their stripe_customers row, and creates a Stripe customer portal session returning to /pricing./api/billing/subscription cancels or resumes the current user's active Stripe Pro subscription, and /dashboard/billing renders localized in-dashboard plan state and self-serve billing actions.web/services/billing/purchase.ts is the shared idempotent recorder used by both /api/billing/complete and /api/stripe/webhook. It attaches email to the purchaser, records billing_email_claims on conflict, and never cross-grants based on an unverified email.cmuxPlan in Stack clientReadOnlyMetadata is the only entitlement VM code reads. cmuxVmPlan manual override wins.resolveProPlanStatus ORs legacy Stack products with active stripe_subscriptions DB rows./api/stripe/webhook is signature-verified, insert-first idempotent through stripe_webhook_events, safe for foreign events in the shared Stripe account, and gates cmux handling on metadata.app === "cmux". Return 2xx only after durable writes; return 500 to make Stripe retry.
Dev Workflow
- Use
web/scripts/stripe/dev-stack.sh.
- The tagged app bakes
CMUX_PORT into Info.plist; run the dev server on the tag's printed port. Do not hardcode a port.
- Per-branch Docker Postgres ports can collide with other agents' containers. Use
--db-port and never stop containers you did not create.
/app-pricing requires cmux_app=1.cmux_scheme threads the native deeplink return scheme. cmux-dev-* schemes are honored only for localhost requests.
Repeat Dogfood
- Use a private window for a fresh anonymous buyer.
- Use
web/scripts/stripe/dev-reset.sh <email> to un-Pro a signed-in dev account before retesting checkout.
- The "already active" short-circuit lives in
/api/billing/checkout.
Test-Mode Resources
- Product:
prod_UpIQRE6cj0nFjs.
- Lookup keys:
cmux-pro-monthly ($30/mo) and cmux-pro-yearly ($240/yr).
- Staging webhook endpoint:
we_1Tq1SZGhInAdn3JbWJReKNEN forwarding to cmux-staging.vercel.app; secrets are already in the cmux-staging Vercel project.
Feature Flags
pro-upgrade-ui-enabled-release (PostHog id 741838) gates all Pro UI and stays OFF in release until launch. DEBUG builds default the UI on.pro-checkout-enabled-release (PostHog id 741839) routes the public pricing CTA.cmux __internal_flags, once merged, inspects and overrides flags locally.
Prod Runbook
- Run
web/scripts/stripe/provision-live.sh with an operator key, add the two Vercel envs, deploy, validate live with a 100 percent-off promotion code purchase, then cancel.
- DB migrations go through
bun run cloud-vm:preflight, bun run cloud-vm:migrate -- staging, staging deploy, then bun run cloud-vm:migrate -- production. See the Cloud VM ops flow. Never run migrations from builds.
Testing Gotchas
bun mock.module is process-global, so every module mock must carry every real export other suite files import. Missing exports may surface only in CI's test order as Export named X not found.- Tests must not depend on
DATABASE_URL being set.
- drizzle-1.0-beta wraps pg errors in
DrizzleQueryError; read error.cause for the pg code and constraint.
Route Placement Gotcha
Pages outside app/[locale] need a proxy.ts bypass, like /app-pricing and /billing, or next-intl rewrites them into the locale tree and they 404 through missing root layout tags. Those subtrees also need their own layout with html and body.
