Case studies

Six businesses, in their own words

What each business needed, what I delivered, and what changed. Client names are left out on purpose.

  1. 01Food ordering from your seat at events and food trucksUnited States · May 2026 to present
  2. 02Searchable contract examples for lawyers, drawn from SEC filingsUnited States · Mar 2022 to Apr 2025
  3. 03Point of sale, delivery and inventory for licensed retailersUnited States · Aug 2021 to Apr 2023
  4. 04One catalogue for seven tour operators, and a cruise retailer off its legacy siteUnited States · Oct 2023 to Sep 2025
  5. 05An e-wallet for consumers and merchants, plus a marketplaceSingapore · Jun 2020 to Jul 2021
  6. 06Car-rental comparison and booking across 10+ suppliersAustralia · Mar 2015 to Apr 2020

Case study 1 of 6

Food ordering from your seat at events and food trucks

When
May 2026 to present
Where
United States
Role
Lead engineer, team of 4-5

The problem

Fans order from their seats and vendors print tickets in the truck. The platform was heading to launch with prices partly decided by the phone app, open security gaps and no automated safety net.

The outcome

I wrote over 95% of the backend changes since joining and shipped 130+ fixes and features through QA. Across three security audits, I fixed 100+ security issues. The platform is in its pilot stage.

What I delivered

  • Moved all pricing and payments to the server, so the app can't change what a customer pays
  • Built the money rules: commission, sales tax and service charge set per event, per vendor or platform-wide, matching to the cent on quote, charge and receipt
  • Ran three security audits across the platform, then closed what they found: an open door that let anyone run commands on the server, account takeover between vendors, customer data exposed publicly, leaked keys and brute-force logins
  • Automated tests that block any release that would break ordering or payments, and faster deployments
  • Vendor tools for busy event days: pausing orders, kitchen printing, pickup codes and search
Next: Searchable contract examples for lawyers, drawn from SEC filings

Case study 3 of 6

Point of sale, delivery and inventory for licensed retailers

When
Aug 2021 to Apr 2023
Where
United States
Role
Lead engineer, team of 2-3

The problem

Licensed retailers sell in-store, by delivery and online, and every regulated sale must be reported to the state exactly once, only within legal selling hours. Getting it wrong puts their licence at risk.

The outcome

Top backend contributor, with 58% of the admin and API code and 50% of the point-of-sale app. Led a team of 2-3, helped with hiring, and kept the platform in step as the company expanded into more US states.

What I delivered

  • State compliance reporting built into every sale: blocked outside legal hours, never reported twice, and failures kept for retry
  • One order system for the till, delivery drivers, pickup and the online store, with discounts, taxes, delivery fees and purchase limits
  • Purchasing from brands, stock received against each order, and a shared product catalogue with stock per store
  • Sales, tax and product reports by day, month, hour and area for owners
  • Started the wholesale product from the retail platform, and built the public website and self-service onboarding from the first commit
Next: One catalogue for seven tour operators, and a cruise retailer off its legacy site

Case study 4 of 6

One catalogue for seven tour operators, and a cruise retailer off its legacy site

When
Oct 2023 to Sep 2025
Where
United States
Role
Proposed and designed the architecture

The problem

A cruise and tour retailer sells trips from seven tour operators, each publishing tours and prices in its own format, on its own schedule. Customers need one consistent page, and the whole business ran on an ageing site that every change risked breaking.

The outcome

Tour and search pages became several times faster (reported). I was the #1 contributor to the API and wrote nearly half of the new website's code (749 of 1,579 changes).

What I delivered

  • One tour page and one search for all seven operators, so adding an operator means adding one small piece, not a rebuild
  • Automated daily updates that back up data first, never leave the site half-updated, and alert the team the moment a job fails
  • Pricing rules that let sales run discounts and private offers by tour, city, price band and trip length
  • Quote requests built from the same data as the page, so the email sales receives always matches what the customer saw
  • Moved the admin team off the old site screen by screen, then led the new public website: 152 pages
  • Blocking for bots and brute-force logins across the site
Next: An e-wallet for consumers and merchants, plus a marketplace

Case study 5 of 6

An e-wallet for consumers and merchants, plus a marketplace

When
Jun 2020 to Jul 2021
Where
Singapore
Role
Main contributor

The problem

Customers send money, pay merchants by QR code across several currencies and withdraw to banks. Every transfer has to apply fees and rewards correctly and must never be applied twice.

The outcome

Closed the race conditions behind a double-spend risk found by a penetration test. Main contributor to the wallet (about 42% of changes) and builder of 81% of the seller portal.

What I delivered

  • The core money movement: transfers, QR payments, fees, rewards and currency conversion, each checked before any money moves and fully undone if a step fails
  • Fixed the race conditions a penetration test found: send-money and load-money requests arriving at the same moment could spend the same balance twice. Each transfer is now all-or-nothing, and repeat withdrawal and refund submits are blocked
  • Card and bank top-ups that verify every payment confirmation and never credit the same payment twice
  • Withdrawals to banks, with batch processing and exports for the finance team
  • Sign-up, identity checks and permissions for customers, merchants, agents and admins
  • Closed the security gaps: staff reaching beyond their permissions, customers seeing others' withdrawals, and unsafe pages
  • Most of the marketplace seller portal, where sellers in several countries list, ship and get paid through the wallet
Next: Car-rental comparison and booking across 10+ suppliers

Case study 6 of 6

Car-rental comparison and booking across 10+ suppliers

When
Mar 2015 to Apr 2020
Where
Australia
Role
Senior backend developer

The problem

Travellers compare and book across many rental companies, each with its own system and rules. Airline and airport partners want their own branded sites, and a booking can fail halfway at the supplier, the payment or the email.

The outcome

4M+ rentals in 5 countries, with sub-second responses (reported). One of the two largest contributors to the booking system and admin over five years.

What I delivered

  • 10+ rental suppliers behind one search and booking flow that behaves the same for every one of them
  • Bookings that survive failures step by step, protect customers from price rises and refund automatically if the price went up
  • Payments, deposits, refunds, and a paid membership and insurance sold alongside the rental
  • Search by place that finds the nearest pickup and return locations, with tools for staff to keep supplier locations current
  • Admin tools for customer service, commission rules and promotions, and branded emails with alerts to staff when something looks wrong
  • Helped replace the old booking engine, and moved its historical bookings across

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