cmux-billing

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

Read 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. The "already active" short-circuit lives here.
• /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 active Stripe Pro subscription; /dashboard/billing renders localized in-dashboard plan state and self-serve actions.
• web/services/billing/purchase.ts is the shared idempotent recorder used by /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; a cmuxVmPlan manual override wins. resolveProPlanStatus ORs legacy Stack products with active stripe_subscriptions 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, never a hardcoded one.
• Per-branch Docker Postgres ports 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, and web/scripts/stripe/dev-reset.sh <email> to un-Pro a signed-in dev account before retesting checkout.
• Fake payment, two ways: web/scripts/stripe/dev-grant.sh <email> writes cmuxPlan: "pro" directly (instant, no checkout; undo with dev-reset). For the full checkout path at $0, enter promotion code CMUXDEV100 in test-mode checkout — a 100%-off forever coupon in the test account; allow_promotion_codes is already set on checkout sessions.
• Newer Stripe CLI prints stripe config --list as key=value (older builds used key = 'value'); dev-stack.sh and dev-reset.sh accept both. If key extraction fails, re-run stripe login.

Test-mode resources

Product prod_UpIQRE6cj0nFjs. New checkouts use cmux-pro-monthly ($30/mo) and cmux-pro-yearly-288 ($288/yr, equivalent to $24/mo). Keep cmux-pro-yearly ($240/yr) active for grandfathered subscriptions. Staging webhook endpoint we_1Tq1SZGhInAdn3JbWJReKNEN forwards to cmux-staging.vercel.app; its 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 it on. Public Pro and Team pricing CTAs always route through /api/billing/checkout, never the download confirmation page. 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: bun run cloud-vm:preflight, bun run cloud-vm:migrate -- staging, staging deploy, then bun run cloud-vm:migrate -- production. Never run migrations from builds. See the Cloud VM ops flow.

Gotchas

• bun mock.module is process-global, so every module mock must carry every real export other suite files import. A missing export can 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.
• 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.