Payment Integration Developer for Hire
Deposits, payouts, and platform fees — wired in and reconciled correctly.
I build the payment flows that move real money between real parties — buyer deposits, seller payouts, platform fees, subscriptions, and refunds. Payment code is the part of your system that can't be 'mostly right' — I design for idempotency, webhook reliability, and clean reconciliation from day one, not bolted on after a bug report.
What you get
What I Deliver
Payment gateway integration
Stripe, PayPal, or a custom gateway wired into your checkout, subscription, or bidding flow — server-side charge creation, client-side confirmation, and proper error handling.
Deposits, payouts & escrow-style flows
Buyer deposit capture, held funds, and seller/vendor payouts with fee splitting — built for marketplaces and auction platforms where money passes through multiple parties.
Webhook-driven reconciliation
Idempotent webhook handlers that keep payment status in your database in sync with the gateway — handling retries, out-of-order delivery, and duplicate events safely.
Refunds, disputes & failure handling
Explicit handling for declined charges, partial refunds, chargebacks, and disputes — not just the happy path.
Subscription & recurring billing
Plan changes, proration, dunning for failed renewals, and customer-facing billing portals using Stripe Billing or an equivalent.
Audit trail & reporting
Transaction logging, invoicing, and admin-facing reporting so finance and support teams can see exactly what happened to every payment.
Is this right for you?
Who I Work With
- Marketplaces and auction platforms handling buyer deposits and seller payouts
- SaaS products adding subscription billing for the first time
- Platforms migrating off a fragile, hand-rolled payment integration
- Founders who need PCI-conscious architecture without becoming payments experts themselves
- Teams that have had payment webhook bugs cause reconciliation issues in production
Tech Stack
Real-world result
Seen in Production
Everyday Car Auctions — UK Auction Platform
Built the payment flow behind a live reverse-auction marketplace — buyer deposit capture on bid placement, seller payout calculation net of the ~8–9% + VAT platform fee, and webhook-driven reconciliation so payment status always matches the auction outcome, even under concurrent bidding.
Read the full case studyCommon Questions
Stripe or PayPal — which should I use?
Stripe for most marketplace and SaaS platforms — Stripe Connect handles multi-party payouts and fee splitting cleanly, and the API and webhook model are more developer-friendly. PayPal is worth adding alongside Stripe when your audience expects it as a checkout option, but I rarely recommend it as the only processor for a marketplace.
How do you handle payouts to sellers or vendors?
For marketplaces, I use Stripe Connect (or an equivalent) to route funds to connected accounts, calculating platform fees at the point of transfer rather than as a separate reconciliation step. Payouts are triggered by clear business events — an auction ending, an order being fulfilled — not on a fixed timer that can drift out of sync with what actually happened.
What happens if a webhook is delivered twice or out of order?
Every webhook handler I write is idempotent — it checks the event ID against what's already been processed before applying any state change, so duplicate or out-of-order delivery can't double-charge, double-payout, or corrupt state. This is the single most common source of payment bugs, and it's designed against from the start.
Can you fix an existing payment integration that has bugs?
Yes. I audit the existing flow first — how charges are created, how webhooks are verified and processed, and where state can drift between your database and the gateway — then fix the specific failure modes rather than rewriting the whole integration.
Do you handle PCI compliance?
I build so that card data never touches your servers — using Stripe/PayPal hosted fields, Elements, or their SDKs — which keeps you on the simplest PCI SAQ tier. I'm not a compliance auditor, but the architecture is designed to keep your compliance scope as small as possible.
Ready to get started?
I take 1–2 clients at a time to ensure quality. Get in touch and let's talk about your project.
Contact Me