Stripe Billing & Subscription Management for SaaS

The Complexity of SaaS Billing

Accepting a one-time $50 payment for a t-shirt is easy. Architecting a B2B SaaS billing engine is incredibly difficult.

In SaaS, you have to deal with:

• Proration: A customer upgrades from the $50/mo plan to the $100/mo plan halfway through the month. How much do you charge them today?
• Dunning (Failed Payments): A customer's credit card expires. You need to email them, retry the card 3 days later, and gracefully lock their account on day 7 if it still fails.
• Usage-Based Metering: Charging a base fee of $20/mo, plus $0.05 per API call over 10,000 calls.

Instead of writing this math from scratch, DevApps Technology integrates Stripe Billing to handle the heavy lifting, while engineering the robust webhook architecture required to keep your database perfectly in sync.

1. The Core Data Model

Your PostgreSQL database must not be the "source of truth" for financial math, but it must mirror Stripe's state to control software access.

We engineer your tenants or workspaces table to include critical fields:

• stripe_customer_id: (e.g., cus_12345)
• stripe_subscription_id: (e.g., sub_67890)
• stripe_price_id: Maps to your "Pro Plan" vs "Enterprise Plan".
• subscription_status: active, past_due, canceled, trialing.

When a user logs in, the Next.js frontend checks the subscription_status in your local database to determine if they can access the premium dashboard.

2. The Webhook Architecture (The Source of Truth)

Because subscriptions renew in the background (while the user is asleep), your software must listen for Stripe's asynchronous events.

We build secure Node.js Webhook Endpoints.

1. Stripe charges the customer's card automatically on the 1st of the month.
2. Stripe fires an HTTP POST request to https://yoursaas.com/api/webhooks/stripe.
3. Security Check: Our Node.js server validates the Stripe-Signature header using your secret webhook key to ensure a hacker isn't faking the payload.
4. Event Parsing: We use a switch statement to handle the event type.

switch (event.type) {
  case 'invoice.payment_succeeded':
    // The renewal worked. Update local database to 'active'
    break;
  case 'invoice.payment_failed':
    // The card declined. Update local database to 'past_due'
    // This instantly locks the user out of the premium dashboard
    break;
  case 'customer.subscription.deleted':
    // They canceled. Update local database to 'canceled'
    break;
}

3. Handling Usage-Based Metering

If your SaaS charges based on consumption (like Twilio or AWS), you cannot rely on flat monthly fees.

We integrate the Stripe Metered Billing API.

• Every time a user executes an action in your app (e.g., sending an SMS), we increment a counter in Redis for extreme speed.
• Every hour, a background Cron job flushes the Redis counts and sends an API request to Stripe: stripe.subscriptionItems.createUsageRecord.
• At the end of the billing cycle, Stripe perfectly calculates the math: (Base Fee) + (Total Usage * $0.05), generates an invoice, and charges the card.

4. The Stripe Customer Portal

Instead of building complex UI screens for users to update their credit cards, download PDF invoices, and cancel their plans, we integrate the Stripe Customer Portal. With one API call, we generate a secure link that drops the user into a Stripe-hosted UI where they manage their own billing, saving you weeks of frontend React development.

Is your billing engine a mess of spaghetti code? A flawed billing integration will cost you MRR. Contact DevApps Technology to architect a bulletproof Stripe Billing pipeline.