Webhook events arrive late, out of order, or twice, and naive handlers double-charge or double-credit a customer.
Fintech & Payments
Fintech & Payments Laravel Development
Payment logic does not forgive sloppy code. We build billing and transaction systems around idempotency keys, double-entry ledgers, and nightly reconciliation, so every dollar that moves is traceable back to a webhook event.
What we get right by default
- Idempotency keys on every webhook handler
- Double-entry ledger, not a single balance column
- Queued retries with exponential backoff
- Nightly reconciliation against processor reports
How we think about it
Where Fintech & Payments projects actually break
Most payment bugs are not about the payment gateway. They are about what happens after the webhook fires: a Stripe event arrives twice because the endpoint took too long to respond, a queue worker retries a job that already succeeded, or a subscription upgrade mid-cycle produces a proration amount nobody double-checked. We design the receiving end of the payment flow first: every webhook handler is idempotent by design, backed by a processed-events table keyed on the event ID, so a duplicate delivery is a no-op instead of a double charge.
For the ledger itself, we avoid the common shortcut of a single "balance" integer on the user table. We build double-entry transaction logs (debit and credit rows tied to an account, never a mutated balance in place) so every balance can be recomputed and audited independently of the application code. Nightly reconciliation jobs then compare our internal totals against the processor's own balance transaction API (Stripe, Paddle, or a regional gateway), and flag drift before a customer notices it, not after.
Where projects go wrong
Common Fintech & Payments backend challenges
Compliance requirements (PCI DSS scope, KYC/AML checks) demand strict data handling that generic CRUD code does not provide out of the box.
Subscription upgrades, downgrades, and cancellations mid-cycle produce proration math that is easy to get wrong and hard to unit test without real scenarios.
Reconciliation between your internal ledger and the payment processor drifts silently for weeks until finance notices the numbers do not match.
What we build
Systems we build for Fintech & Payments
Billing and subscriptions
Plans, proration, invoices, dunning, and usage-based billing built on Laravel Cashier (Stripe/Paddle) or a custom subscription engine when the billing model does not fit an off-the-shelf package.
Payment gateway integration
Stripe, Paddle, PayPal, Braintree, and regional processors, with signature-verified webhooks, an idempotency table, and queued processing so a slow handler never blocks the gateway's response window.
Wallet and ledger systems
Double-entry balance tracking with database-level row locking on transfers, full transaction history, and a reconciliation command that runs against the processor's reporting API.
Fraud and compliance checks
Rate limiting on payment endpoints, KYC/AML hook points for a verification provider, and an audit log that records who touched what financial record and when.
Tech stack
Tools we typically reach for
FAQ
Fintech & Payments project questions
Do you build custom billing, or use Stripe/Paddle's hosted billing?
Depends on the plan model. If Stripe Billing or Paddle covers your pricing (flat tiers, simple usage add-ons), we build on top of it with Laravel Cashier. If you need usage-based billing tied to a metric Stripe doesn't track natively, or a wallet/credit system, we build a custom ledger instead.
How do you prevent double-charging from duplicate webhooks?
Every webhook handler checks an idempotency table keyed on the provider's event ID before processing. A duplicate delivery is recognized and skipped, not reprocessed.
Can you migrate us between payment processors?
Yes. We've handled Stripe/Paddle/PayPal migrations, including re-mapping existing subscriptions and payment methods where the provider supports it, and building a bridge period for customers who need to re-enter payment details.
Do you handle PCI compliance?
We build with PCI scope reduction in mind by default: card data goes through hosted fields (Stripe Elements, Paddle Checkout) so raw card numbers never touch our servers. Full PCI DSS certification is a compliance process on your end; we build the technical foundation that keeps that process simple.
More industries
Other sectors we build for
Ready to talk about your Fintech & Payments project?
Send the current scope, backlog, or problem list and we will suggest the next step.