Look, i write code from 9 to 5 at my day job. By 6 PM I'm usually tired. By 9 PM, after dinner and half-watching whatever my wife has on Netflix, I open my laptop and work on side projects. Not glamorous ones. Not "I built a SaaS in 48 hours" ones. The boring kind — the kind where I stare at a spreadsheet and try to figure out which $47.50 actually came from where.
That's how I got into affiliate marketing for AI tools. Not because I had some grand vision. Because my Notion tracker showed me that one quiet income stream was outperforming three of my more "impressive" projects combined. Once I saw the per-hour math, I couldn't unsee it.
Let me tell you how I got there, what the numbers actually look like, and what I'd do differently if I were starting from zero today.

The Side Hustle Reality Check

Here's the thing nobody tells you about developer side hustles: most of them don't pay off in the first year. Or the second. I built a Chrome extension that maybe 200 people use. I launched a Notion template that sold 14 copies before I gave up. I even tried selling a Python course on Gumroad, which generated exactly $128 in three months.
I tracked every dollar in Notion — yes, I have a whole database for this, because I'm the kind of person who needs to see numbers to believe things are real. When I looked at my side hustle tracker at the end of last year, one row kept standing out: my affiliate income from promoting AI APIs.
It wasn't huge. But it was passive. And once I understood the commission structure, I realised the per-hour economics were better than anything else I was doing. Let me break down the math for you.

Here's the Math (Because Math Doesn't Lie)

The affiliate program I ended up going deep on — Global API — has a commission structure I'll be transparent about because it's the whole reason I stuck with it:

• 15% on every first-order a referral makes
• 8% recurring on every subsequent order that same customer places
• 10% premium commission if the referral upgrades to a premium plan Let me run some numbers with you