The situation
HIO, short for Hole in One, matches golfers across the United States for virtual matches, pairing players by skill level and by when they want to play. The idea was Joshua Chung's.
Joshua hired a development team, who helped design the app and built a native version. It never worked as expected. The build was full of bugs, and then the team stopped responding.
We had worked with Joshua before, on a crowdfunding web app for hospital bills in 2020, so he brought the project to us to take a look.
What we built
We started with the codebase the previous team left behind and concluded that rebuilding would cost less than repairing it. We also recommended a progressive web app rather than another native build: one codebase that runs on every device, and a proof of concept that let HIO validate the idea with real players before committing further.
Product and architecture. We brainstormed and designed the app alongside Joshua, then architected it and chose a stack to match: a Next.js frontend on a relational Supabase database, designed around the data the matchmaking actually needs.
Payments and messaging. We advised on the tooling and integrated it: Stripe for payments, and Twilio for phone number verification and text messages.
Skill ratings. Players are rated with the TrueSkill algorithm, which assigns each golfer a skill level without being skewed by which courses they happen to play or by their handicap.
Matchmaking. A custom matching algorithm pairs players using geolocation and settings that admins can configure, such as the allowed difference in skill level and tee times.
Course data. Par and difficulty for each hole come from data available for golf courses across the United States.
Interface. A custom UI component library, responsive across devices, with animations that lean into the competitive, gamified side of the app.
We iterated the MVP with live players testing it in real golf matches, and set up a deployment pipeline so Joshua can push updates whenever he needs to.
The security incident
Partway through the project we caught a security breach: malware spreading through a compromised NPM package. It did not come from our code, but we treated it as urgent and worked on it until it was resolved.
Then we made sure it could not happen the same way again. We hardened the repository and moved development into a Docker dev container, so the project's dependencies run inside an isolated environment rather than directly on a developer's machine. We have since applied the same hardening to every client project we work on.
“Danny noticed this right away and immediately spent every hour fixing the issue and came up with a very safe solution to ensure this would never happen again.”
The result
HIO now runs as a fully functional, multi-user PWA. Live matches are being played, and more golfers are joining as Joshua takes the app to more golf courses.
“He fixed a broken codebase written by unreliable contractors and then also created a ready to deploy pipeline that allows me to push updates as needed. Working with Danny is easy and efficient - which are the two essentials for finding a partner. He communicates efficiently, logs all requirements, delivers on time, promptly fixes any live site related issues.”
What HIO says.
Which problem were you facing before we worked together?“Lots - I needed someone to take over a broken codebase built by unreliable contractors. I had previously worked with Danny and his agency Sleek App, and I knew he could get the job done in fixing the code + creating a reliable ready-to-deploy pipeline.”
What were your results from our work together?“I've worked with Danny/Sleek App on two projects so far.
The first one was before AI and he helped me manifest my idea of creating a health webapp. He delivers the product exactly as contracted and if there are any mixups or preferences that I had, he addressed it promptly.
The current project, he fixed a broken codebase written by unreliable contractors and then also created a ready to deploy pipeline that allows me to push updates as needed. There was an interesting scenario this time around when there was a security breach that he noticed (Disclaimer: the security breach was not caused by Danny's code but moreso a malicious virus that was spreading across GitHub). Danny noticed this right away and immediately spent every hour fixing the issue and came up with a very safe solution to ensure this would never happen again.
Other things to note, Danny revamped and essentially rebuilt my current golf app into something that is amazing and used with my friends and few other golfers. He built a live matchmaking app based on golfing skill points.”
What was working with me like?“Working with Danny is easy and efficient - which are the two essentials for finding a partner. He communicates efficiently, logs all requirements, delivers on time, promptly fixes any live site related issues.”
Who or what kinds of businesses would you recommend me to?“Any business honestly haha”
