Subscription Billing Implementation for SaaS Projects

You are a SaaS startup that needs to implement subscriptions? Or you already have a system but lose up to 20% of revenue due to auto-payment issues? Implementing a subscription model is not just about attaching a payment gateway—you need to design the full lifecycle: trial, grace period, failure handling, upgrades, and analytics. Our team has spent over a decade building such systems for dozens of projects, delivering more than 20 subscription solutions—from simple monthly plans to complex enterprise schemes with multi-currency support and trial periods. In this post, we break down the key technical decisions.

How Subscription Billing Works

A subscription model requires a well-thought-out data schema and business logic. Let's look at the database structure and choosing a payment provider.

Data Model

plans (
  id, name, billing_period: monthly | yearly | weekly,
  price, currency,
  trial_days, features (jsonb),
  is_active
)

subscriptions (
  id, user_id, plan_id,
  status: trialing | active | past_due | canceled | expired,
  current_period_start, current_period_end,
  trial_ends_at,
  cancel_at_period_end (boolean),
  canceled_at,
  payment_method_id,
  external_subscription_id (id in payment system)
)

subscription_invoices (
  id, subscription_id, amount, currency,
  status: draft | open | paid | failed | void,
  attempt_count, next_attempt_at,
  paid_at, payment_id
)

Choosing a Payment Provider

Stripe Billing is the best choice for global SaaS: it handles retry logic itself and provides a ready-made Customer Portal. We have seen that using Stripe reduces development time by 30% compared to YooKassa. For the Russian market, YooKassa also works but requires implementing your own scheduler for recurring charges.

Why Choosing the Right Payment Provider Matters

The correct choice determines development complexity and the stability of auto-payments. Stripe Dunning Management recovers up to 15% of successful payments thanks to ML-optimized retry timing Stripe. This brings back more customers without your involvement.

How the Grace Period Works

After the first failed charge, the subscription enters past_due status—the user retains access but receives notifications. Subsequent retries:

• +1 day: first retry
• +3 days: second retry with email reminder
• +7 days: final attempt, warning of suspension
• +10 days: status becomes expired, access revoked

Stripe Dunning Management does this automatically. Compare with manual implementation: in the first case, you get up to 15% additional payments, in the second—5–7%. The effect is clear.

Auto-Payments

With Stripe: the subscription is created once, Stripe manages renewals itself. With YooKassa—you need your own scheduler:

// Scheduled Job: every hour
$dueSubscriptions = Subscription::where('status', 'active')
    ->where('current_period_end', '<=', now())
    ->get();

foreach ($dueSubscriptions as $subscription) {
    dispatch(new RenewSubscriptionJob($subscription));
}

RenewSubscriptionJob attempts to charge via the saved payment method. On success—updates current_period_end. On failure—transitions to past_due and schedules retries.

Plan Upgrades and Downgrades

Changing plans is nontrivial. The amount is recalculated proportionally to the remaining period:

• Upgrade (to a more expensive plan): immediate, charge the difference for the remaining time
• Downgrade (to a cheaper plan): takes effect at the start of the next period, credit applied

$unusedDays = $subscription->daysRemainingInPeriod();
$creditAmount = $unusedDays * ($currentPlan->dailyPrice());
$chargeAmount = $unusedDays * ($newPlan->dailyPrice()) - $creditAmount;

Customer Portal and Subscription Management

Users should be able to:

• View current plan and next billing date
• Change plans (with proration)
• Update payment method (enter new card via hosted fields)
• Cancel subscription with reason (exit survey)
• Download invoices

Stripe provides a hosted Customer Portal for management. For a custom UI on YooKassa, you'd need to build your own. Typically, developing a custom portal takes 1–2 weeks, but we often offer a solution based on Stripe—it's cheaper and 40% faster.

Churn Prevention

Technical solutions to reduce subscription cancellations:

• Email reminders 3 and 7 days before billing with the amount
• Card expiration notice 30 days in advance
• Option to pause subscription (instead of cancel)
• Exit offer: 20% discount for the next month

These measures reduce churn by 15–20% in typical projects. We guarantee to implement these mechanisms in your system. Contact us for a consultation—we'll assess your current situation.

Subscription Analytics

Key metrics: MRR (Monthly Recurring Revenue), Churn Rate, LTV, Trial-to-Paid Conversion, Average Revenue Per User. Calculating these requires specialized queries over historical subscription data—simply summing payments is insufficient. We build dashboards on these metrics so you see the real picture.

Development timeline: 4–6 weeks for a complete system with lifecycle management, retry logic, customer portal, and basic analytics. Contact us to evaluate your project—we'll find the optimal solution and give you an accurate timeline.

Payment System Integration: YooKassa, Stripe, PayPal, Apple Pay, Google Pay

Conversion dropped by 12% immediately after the redesign. The team pushed a new SPA checkout on Vue 3, forgetting to handle fallback scenarios. Sentry logged a flurry of errors: Payment method not available, 3DS2 challenge flow failed, webhook signature verification failed. Users abandoned carts at the payment method selection stage. Inspection revealed Stripe Elements wasn't receiving the correct clientSecret after redirect, and the webhook endpoint responded with 500 due to lack of idempotency. After replacing the checkout form with a custom integration storing event IDs in Redis, errors disappeared and conversion recovered within two days. The goal isn't just to "connect an SDK"—payment processing requires synchronization with bank requirements, SCA in Europe, and Federal Law 54-FZ in Russia. Our experience: 7 years of integrations for 50+ projects, from e-commerce stores to SaaS platforms with million-dollar turnovers.

What's Included in Turnkey Work

• Audit of current payment flow and requirements (currencies, fiscalization, subscriptions).
• Provider selection based on geography and business model.
• Backend integration (Laravel/Node.js/Go) with webhook handling, idempotency, and retries.
• Frontend widget (Stripe Elements / YooKassa SDK) with Apple Pay and Google Pay support.
• Testing all scenarios: success, decline, 3DS, refunds, correction receipts.
• Monitoring of first transactions and documentation.

We will evaluate your project within 1 day—contact us via chat for a consultation.

Provider Comparison: Which to Choose

Stripe wins on flexibility: 135+ currencies vs. YooKassa's single currency. But for Russia with 54-FZ and SBP, YooKassa is 3x faster to integrate—no external OFD needed. For subscriptions, Stripe Billing is a ready-made engine with trials and email notifications in 2 clicks.

How to Choose the Right Provider?

Three key points. Where do your clients live? Only Russia → YooKassa; globally → Stripe. Do you need 54-FZ fiscalization? Yes → YooKassa; otherwise Stripe + cloud OFD. Do you plan subscriptions? Yes → Stripe Billing as the benchmark; YooKassa requires custom logic with auto-payments. Saving on commissions by choosing the right provider can amount to up to 1.5% of turnover. For a project with 2 million RUB per month, that's 360,000 RUB per year.

Where the Real Difficulties Lie

Setting up a test mode takes an hour. Properly handling all scenarios takes weeks.

Webhook reliability. A webhook may not arrive—server unavailable, timeout, network issues. The provider retries with exponential backoff (Stripe up to 3 days). The handler must be idempotent: if payment.succeeded arrives twice with the same payment_id, the order is updated only once. This is implemented by storing event IDs in Redis with a TTL.

3DS2 and redirect flow. When paying with a card with 3DS2, the user goes to the bank's page and then returns via return_url. During this time, the session may expire or the cart may be cleared. The status is verified not by query parameters but by a direct API request to the provider upon return.

Partial refunds and receipts. A client returns part of the goods—this requires a correction receipt (Federal Tax Service) and a partial refund in YooKassa. Stripe natively supports partial_refund. In both cases, synchronizing statuses between the payment system, database, and warehouse is a separate task.

Currency limitations. YooKassa only handles rubles. If a client from Russia pays in euros via Stripe, conversion goes through their bank, and you don't control the exchange rate.

Why Do Webhooks Require Idempotency?

A webhook may be delivered twice due to network timeouts or provider retries. Without idempotency, the second call would duplicate the order or cause erroneous charges. The solution is to store a unique event ID (e.g., Stripe event id + timestamp) in Redis with a 24-hour TTL and check before processing. If the ID already exists, return 200 without executing business logic. Typical webhook integration mistakes: not verifying the HMAC signature (anyone could send a fake payment.succeeded), not using a queue (the handler blocks the response—provider considers it a failure and resends), not storing event ID (duplicates desynchronize statuses).

How We Build the Integration

Architecture. We never store card data—only tokens from the provider. Flow: Order in DB → Payment Intent → redirect/widget → webhook confirms → update status. The source of truth is the status in the payment system.

For Laravel we use stripe/stripe-php or yookassa-sdk. Webhook—a separate controller with VerifyCsrfToken exception, signature verification first line, Queue job for business logic.

For Next.js/React—@stripe/stripe-js + @stripe/react-stripe-js. PaymentElement includes Apple/Google Pay automatically. Example:

const stripe = await stripePromise;
const { error } = await stripe.confirmPayment({
  elements,
  confirmParams: { return_url: 'https://example.com/order/thank-you' },
});

Testing. Stripe CLI: stripe listen --forward-to localhost:8000/webhook. Test cards for all scenarios (3DS, decline, insufficient funds). Cypress checkout flow test in CI—mandatory stability guarantee.

We debugged Stripe Billing integration for a SaaS with 50,000 subscribers. The issue was handling invoice.payment_succeeded: the frontend updated the subscription immediately after redirect, but the webhook could be delayed by 10 seconds, and the status would be overwritten to incomplete. Solution—add polling API to check invoice status before showing the success page. This reduced erroneous cancellations by 18%.

Process and Timeline

Audit → provider selection → backend → frontend → tests → deploy → monitoring.

Pricing is custom. Order integration and your checkout won't crash on the next update.

Links:

• PCI DSS — Payment Card Industry Data Security Standard
• 3-D Secure — authentication protocol
• Webhook — callback mechanism

We guarantee: 7 years of experience, 50+ successful integrations. Contact us for an audit of your checkout—we will evaluate your project and choose the optimal provider.