Building a Subscription Platform from Scratch: A Love Letter to My Old Code

I didn’t realize I was building something that would matter so much to me.

When I started writing the first line of subscription-api in Go, I was just trying to solve a problem: how to manage user subscriptions across Apple IAP, Alipay, and WeChat Pay. There was no team, no architecture meeting, no CI/CD pipeline. Just me, a text editor, and a growing sense of ownership.

Over the next few years, I built everything from the ground up:

I write more than 100 thousand lines of code in around 30 thousand commits. I debugged payment callbacks at midnight. I wrote documentation no one would read. I optimized database queries for faster load times. I set up Jenkins to automate deployments – and taught the ops team how to use it.

And then, one day, I left.

It wasn’t because the code was broken. It was because I was tired.

Tired of being told, “What’s the point of writing good code if the boss can’t see it?”

Tired of hearing, “The company might close tomorrow,” with no follow-up, no clarity.

Tired of feeling invisible.

I wanted to make more money – not for luxury, but to buy my mother a home. I thought leaving would solve that. Instead, I ended up with a two-month job on my resume, and a heart full of regret.

The systems I built are still there, frozen in time. No one has touched them since I left. They’re “dead” in the sense that they’re not evolving – but they’re alive in the sense that they still work. They were built to last.

I look at the GitHub repositories now, and I cry. Not because I failed, but because I cared so much.

I cared about clean code.

I cared about reliability.

I cared about making something that worked, quietly, every day.

If I could go back, I wouldn’t change the code.

I’d change how I treated myself.

I’d ask for help.

I’d talk to someone.

I’d remind myself: what you’re doing matters, even if no one says it does.

This blog post isn’t a technical deep dive. It’s a letter to my past self – and to anyone who’s ever built something in silence, loved it deeply, and walked away.

To my old code: thank you for teaching me what it means to be an engineer.

I’m not done yet.