sector
exchanges, wallets, remittance and subscription billing that has to reconcile
An exchange match engine, wallets and payouts, a remittance platform scoped against a formal RFP, and subscription migrations run on live revenue.
- 9
- fintech engagements
- 6.4K
- lines in the match engine
- 10 yrs
- in one financial estate
- 0
- acceptable billing errors
Clutch
the problem
what this sector actually deals with.
Financial software has a property almost nothing else has: being nearly right is worse than being obviously broken. A checkout that fails is an annoyance. A subscription migration that double-charges half your base, or a wallet that credits twice under load, is an incident with a regulator attached.
sound familiar?
- Two code paths can complete the same payment, and sometimes both do
- Subscription migrations have a cutover date and no rollback
- Wallet balances have to survive concurrency, not just work in testing
- Regulated features — KYC, screening, reporting — are not negotiable, and everything else is
- The store platforms have opinions about how you are allowed to take money
what we have built here
systems delivered in this sector.
An exchange match engine
Roughly 6,400 lines of PHP covering the match engine, buy and sell orders, wallet handling, issuance strategies and currency rates — modernised onto current Doctrine and a real test suite.
Wallets, payouts and coins
A two-sided marketplace wallet with one gateway for top-up and another for UPI withdrawals, running against real per-minute paid services.
Outward remittance, scoped honestly
A white-labelled online remittance platform proposed against a formal RFP — with the deferrable items marked in red, so the client had to decide what compliance they were actually willing to postpone.
Live subscription migrations
A WooCommerce Subscriptions migration on a revenue-generating membership base, with two parallel plan types, store credit and a hard cutover date.
the hard part
two paths completed the same order, and three real customers paid for it.
On a live ticketing platform, upfront web orders were being processed concurrently by two routes — the payment provider's success redirect and its webhook — with nothing coordinating them.
- 01
At a live festival, three real orders ended in an inconsistent state: payment taken, order not completed, tickets not sent. Not a load-test scenario. Named orders, real people, at the gate.
- 02
The fix was two-part: isolate the webhook so it only handles the payment types it should, using provider metadata to tell them apart, and apply row-level database locks to the order-completion path so it cannot run twice.
- 03
Then repair the damage — the affected orders corrected in the database, statuses fixed and tickets reissued — and give the client a written explanation of both the cause and the fix rather than a quiet patch.
- 04
The general lesson is the one worth hiring for: if two code paths can complete the same financial transaction, eventually both will, and the day it happens will be your busiest.
what it runs on
the stack we reach for here.
Chosen for the sector requirements and for maintainability over the life of the system.
- Ledgers
- Row-locked completion paths, idempotency keys, reconciled against provider records
- Gateways
- Stripe, Razorpay, Cashfree, PayPlug, EasyPay — chosen per market, not per preference
- Subscriptions
- WooCommerce Subscriptions and custom billing, delivered as must-use plugins so they cannot be deactivated
- Exchange
- PHP match engine on Doctrine, with a test suite
- Compliance
- KYC and document verification flows, tested against mismatched documents on purpose
how an engagement runs
what the first weeks look like.
Model the money first
States, transitions, failure modes and who is allowed to move a balance. On paper, before code, every time.
Decide what is deferrable
On a regulated product, the useful conversation is which compliance elements are genuinely phase two. We will make you answer it.
Build the reconciliation with the feature
Not after. A payment feature without a reconciliation path is half a feature.
Migrate with a rehearsal
Live billing migrations get a dry run against a copy of production before the cutover date, not a hopeful weekend.
selected work
written up in full
The engagements with the detail attached — and the numbers.
01
B2B commerceThe engineering partnership behind a cross-border wholesale marketplace.
Next.js storefront, Python ingestion pipelines, DynamoDB data layer and AWS infrastructure.
02A commission-free ticketing platform built for ownership and scale.
Multi-organiser commerce, Stripe instalments and two native apps in one connected platform.
03
Global logisticsEmbedded product engineering for a global shipping platform.
Rate, tax and duty calculators, server-rendered courier pages and a custom MongoDB CMS.
04A custom furniture marketplace engineered from storefront to infrastructure.
Server-rendered Next.js commerce over a Laravel API, bespoke operations tooling and re-architected AWS infrastructure.
05An AI-native operating system that runs a consultancy lead to invoice.
Discovery briefs, e-signed contracts, Stripe deposits, delivery milestones and time tracking in one operational system.
06A conversion platform for a growing UK boiler-cover provider.
Custom plan configuration, postcode-qualified lead journeys, CRM synchronisation and campaign landing pages.
07A custom Shopify store for a French beauty brand.
Custom theme, customer accounts, loyalty rewards, referrals and gift-with-purchase offers.
08Made-to-measure shutters with live pricing.
A seven-step product builder with live previews, sample orders and supplier tools.
09
AdvertisingA self-service advertising platform for venues.
Campaign creation, audience targeting, in-app ads and reporting linked to venue check-ins.
10Social eventsAn events app with the tools to run it.
Mobile app, backend, advertising tools, a digital marketplace and website.
11Two mobile apps for real-time companionship.
Customer and buddy apps with per-minute billing, wallets, moderation and admin tools.
12Player profiles and discovery for youth football.
Verified profiles, video highlights, coach discovery and safeguarding on web and mobile.
13Websites and a talent platform for DeepSpatial.
Corporate and investor pages, the Xploor talent platform and ongoing releases on AWS Amplify.
14
TravelTour bookings with a custom mobile-first checkout.
A multilingual website connected to the booking API, with deposits, coupons and affiliate tracking.
15One platform for tenders, contracts and accounts.
Supplier tenders, contract management, brokerage accounting and client records.
Teams that trusted us with the thing that matters
UK · Europe · Worldwide
the practices behind it
what this work is made of.
product engineering
Multi-tenant SaaS, marketplaces, ticketing and booking engines — the systems your business actually runs on, built to survive their own success.
web & commerce
Headless WordPress, Shopify and custom checkouts wired to whatever proprietary API the business already depends on.
rescue & security
AI-generated prototypes and stalled builds taken to production, and compromised live systems recovered — audited first, stabilised second, then finished and hardened properly.
reviews · verified on clutch
the people who signed off the work
Clutch★★★★★5.0 / 5.0Across 18 independently published client reviews
“They have a deeper technical knowledge than any web designer I've met to date.”
faq
questions from this sector
Have you migrated a live subscription base before?
Yes, with two parallel plan types, store credit and a fixed cutover date. The operational detail that matters: subscription queries run against active and on-hold statuses only, never pending. That is the kind of thing you learn by doing it, not by reading the docs.
Can you deal with App Store rules on payments?
We have argued a person-to-person services exemption successfully rather than surrendering margin to in-app purchase, and scoped the fallback design in parallel in case the appeal failed.
Do you handle KYC?
Yes, including the unglamorous part — testing verification against deliberately mismatched documents, which is how we found a flow that accepted the wrong country's ID.
Who owns the code?
You do, from day one. On financial systems that matters more than anywhere else.
keep reading
the other sectors we work in.
money moving through code you did not write?
A thirty-minute call with the engineer who would lead the work.