How to Build SaaS Billing With Stripe: Subscriptions, Trials, Coupons

Stripe is the gold standard for SaaS billing. But wiring up subscriptions, trials, and coupons correctly takes more than a quick API call. This guide covers the full implementation — from creating products in Stripe to handling every webhook that keeps your app in sync.

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Step 1: Set Up Stripe Products and Prices

Before writing code, configure your plans in the Stripe Dashboard:

Create a Product for Each Plan

Best practice: Create both monthly and annual prices for each product. Annual plans (with a ~17% discount) improve cash flow and reduce churn.

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Step 2: Implement Checkout

Using Stripe Checkout (Recommended for MVP)

Stripe Checkout is a hosted payment page. You create a session, redirect the user, and Stripe handles everything — card entry, validation, 3D Secure, Apple/Google Pay.

Flow:

1. User clicks "Subscribe" on your pricing page
2. Your API creates a Stripe Checkout Session
3. User is redirected to Stripe's hosted checkout
4. After payment, user is redirected back to your app
5. Webhook confirms the payment and activates the subscription

Key parameters for the Checkout Session:

• mode: 'subscription' — for recurring billing
• customer — attach to an existing Stripe customer (or let Stripe create one)
• line_items — the price ID(s) the user selected
• success_url — where to redirect after payment
• cancel_url — where to redirect if they cancel
• subscription_data.trial_period_days — to add a free trial

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Step 3: Add Free Trials

Trial Without Payment Method

Let users try your product without entering a card. The subscription starts in trialing status. When the trial ends, the subscription becomes past_due if no card is on file.

Best for: Maximizing trial signups (lower friction). Risk: Low conversion if users forget about the trial.

Trial With Payment Method (Recommended)

Collect the card during signup but don't charge until the trial ends. This is the standard SaaS pattern.

Best for: Higher conversion rates (card is already on file). Implementation: Set trial_period_days in the Checkout Session and payment_method_collection: 'always'.

Typical Trial Lengths

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Step 4: Implement Coupons and Promotions

Coupon Types

Creating Coupons in Stripe

Create coupons in the Stripe Dashboard or via API. Then create Promotion Codes that users enter at checkout.

Add to Checkout Session: allow_promotion_codes: true — this shows a "Have a promo code?" field on the Stripe Checkout page.

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Step 5: Handle Webhooks (Critical)

Webhooks are how Stripe tells your app what happened. Your billing system is broken without webhooks.

Essential Webhook Events

Webhook Security

Always verify webhook signatures:

1. Get the raw request body (not parsed JSON)
2. Get the Stripe-Signature header
3. Use stripe.webhooks.constructEvent() to verify
4. Only process the event after verification passes

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Step 6: Add the Customer Portal

Stripe's Customer Portal lets users manage their own subscriptions:

• Update payment method
• View invoices and receipts
• Change plan (upgrade/downgrade)
• Cancel subscription

Implementation: Create a portal session and redirect the user. Takes about 10 lines of code. Configure allowed actions in the Stripe Dashboard under Customer Portal settings.

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Step 7: Sync Subscription Status

Your database needs a subscription table that stays in sync with Stripe:

Golden rule: Never trust the client. Always check subscription status server-side before granting access to paid features.

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Common Mistakes

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Final Thoughts

SaaS billing with Stripe is a solved problem — but it has many moving parts. Get the checkout flow right, handle webhooks properly, and sync subscription status to your database. Everything else (coupons, trials, portal) is built on that foundation.

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Need a billing template? Browse SaaS boilerplates with Stripe built in on MVPHub.

Planning your billing features? Read SaaS Billing Features Checklist.

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