SaaS Dashboard, API, Billing, and Queue Development Checklist

Every SaaS product is built on four core engineering pillars: the customer-facing dashboard, the backend API, the subscription billing system, and the background job queue. Getting each pillar right is non-negotiable for a product that handles real customers and real money. Use this checklist during development and before any production launch.

Pillar 1: The SaaS Dashboard (React Frontend)

• Authentication Guard: All protected routes must redirect unauthenticated users to the login page. The check must happen on the client AND the API—never trust the frontend to be the sole gatekeeper.
• Role-Based UI: Certain features (admin settings, billing management, user invitation) must be conditionally rendered based on the authenticated user's role. Use a custom usePermissions() hook to make this declarative and consistent.
• Loading and Error States: Every data-fetching component must handle three states: loading (skeleton or spinner), success (rendered data), and error (user-friendly message with a retry button). Never show a blank screen or a raw JavaScript error.
• Responsive Design: SaaS dashboards are primarily used on desktop, but key screens (notifications, approvals, mobile access) must work on mobile. Test on a real device, not just a browser emulator.
• Pagination: Any data table with potentially more than 50 rows must be paginated. Never use client-side pagination that loads all records at once.

Pillar 2: The Backend API

• API Versioning: All routes should be prefixed with /api/v1/ from day one. This makes future breaking changes possible without disrupting existing integrations.
• Input Validation: Every API endpoint that accepts user input must validate it server-side. In Laravel, use Form Request classes. In Node.js, use Zod or Joi schemas. Never trust client-sent data.
• Authorization on Every Endpoint: Every route must check not just authentication (is the user logged in?) but authorization (does this user have permission to perform this action on this specific resource?). Use Laravel Policies or Express middleware for this check.
• Consistent Error Responses: All API errors must return a consistent JSON structure. Example: {"error": "Unauthorized", "message": "You do not have permission to delete this invoice."}. Do not leak stack traces to the client.

Pillar 3: Subscription Billing (Stripe)

• Webhook Handler: A dedicated, publicly accessible endpoint (e.g., /webhooks/stripe) that verifies Stripe's signature and processes invoice.paid, invoice.payment_failed, and customer.subscription.deleted events. This is the authoritative source of truth for subscription status.
• Trial Expiration Logic: If you offer a free trial, the system must automatically downgrade or restrict the user's access when the trial expires, even if they never explicitly cancels.
• Proration on Plan Changes: If a user upgrades mid-cycle, the billing must correctly handle proration (Stripe does this automatically if configured correctly with proration_behavior: 'create_prorations').
• Invoice and Receipt Access: Users must be able to access and download past invoices from within the application, linked to their Stripe billing portal.

Pillar 4: The Background Job Queue

• Queue Worker Supervision: In production, queue workers must run under a process supervisor (Supervisor on Linux, PM2 for Node.js) that automatically restarts them if they crash. A queue that is not running means all background jobs silently pile up.
• Job Timeout: Every job must have a maximum execution timeout. A job that runs for 6 hours because it is stuck in an infinite loop will exhaust your queue worker's resources.
• Failed Job Alerting: Any job that fails after all retry attempts must trigger an alert (email, Slack, Sentry). Do not let failed billing or email jobs sit silently in a dead letter queue.
• Idempotent Jobs: Jobs must be safe to run multiple times. If a job is retried (due to a transient failure), running it twice must not produce duplicate data or double charges.

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