I built a side income that pays me every single month for work I did two years ago. Let me explain how, because every dev I talk to is sitting on the same opportunity and most of them are ignoring it.
My name is whatever you want it to be — call me a regular backend dev with a day job that pays the bills but doesn't exactly fund the lifestyle I want. A couple of years back I started writing technical tutorials on my blog. Nothing fancy. Just the stuff I was building at work and on weekends. Then I added affiliate links to the tools I was already using. That move alone changed my monthly cash flow by more than my last two raises combined.
Here's the thing: most developers think affiliate marketing is for influencers and marketing bros. It's not. It's for people who actually use the products they recommend. And in 2026, SaaS affiliate programs — specifically the ones in the AI API space — are the highest-use thing you can do with your existing technical knowledge.

Let me break this down properly.

The Spreadsheet That Changed Everything

I'm a numbers person. Always have been. My Notion dashboard tracks every dollar I earn outside my salary, broken down by source, by month, by hour invested. I started it because I wanted to know which side hustles were actually worth my time and which ones were just noise.
When I added up everything last quarter, the affiliate income from one single program outperformed every other revenue stream I'd been grinding on. We're talking freelance gigs, a small SaaS product I launched, even some crypto trading I'd been doing on the side. The affiliate income beat them all, and here's the kicker — I barely did any work that quarter to earn it.
That's because the commissions are recurring. Let me explain what that means in real terms, because if you've never thought about this carefully, you're leaving serious money on the table.
A one-time commission is a payout you get once and never again. Someone clicks your link, buys a $50 course, you get $10. Done. You have to find another person to click your link to get another $10. It's a hamster wheel.

A recurring commission is a payout you get every single month for as long as the person stays subscribed. Same person, same signup, but you keep getting paid. That's not a side hustle — that's building an asset.

Let Me Show You the Math

This is where my brain lights up. Let's say you spend four hours writing one genuinely useful article about integrating AI APIs into a side project. You publish it on your blog, on Dev.to, on Hashnode. The article ranks for some long-tail search terms. Over time, it pulls in, let's say, 400 views per month.
Of those 400 readers, maybe 1-2% click your affiliate link. That's 4-8 clicks per month. Of those clicks, maybe 2% convert into actual paid signups. That's roughly 0.3-0.6 new referrals per month from a single article.
Now, here's where it gets fun. Each referral is a developer who just signed up for an AI API platform. They're spending somewhere in the $20-150 per month range on API access, depending on their use case. Let me run the numbers:

• First-order commission: 15% of whatever they spend in their first month
• Recurring commission: 8% of whatever they spend every month after that, for as long as they stay If your average referral spends $50/month, that first month earns you $7.50. Then every subsequent month earns you $4 from the same person. Forever. As long as they stay subscribed. Let's look at this over six months for one article:
• Total new referrals from that article over 6 months: 2-4 people
• First-order commissions: 2-4 × $7.50 = $15-$30 total
• Recurring commissions by month 6: $8-$16 per month So you've invested four hours and you're now earning $8-$16 per month, indefinitely, from that single piece of content. Per hour, that's already $2-$4 — and that's just the start. The article doesn't stop working. It keeps earning next month, and the month after that. Now multiply that by ten articles. Now you're at $80-$160 per month. Multiply by fifty articles. You're at $400-$800 per month. From content you wrote once. This is the compounding effect that most developers underestimate. Each piece of content is a little worker who keeps showing up. --- # # Why Developers Specifically Win at This Here's something I've noticed after watching my numbers closely for over a year: developers who get referred through developer-written content stay subscribed longer than customers who come from any other channel. Why? Switching costs. When a developer builds an app on top of an API, they're not casually trying something out. They're integrating it into their codebase, writing wrapper functions, handling error cases, building UI on top of it. Switching to a different provider means rewriting all of that. Most developers won't bother unless they have a really compelling reason. This means the people you refer have above-average retention, which is gold for recurring commission programs. I have referrals from early 2024 who are still paying monthly subscriptions. That means I'm still earning 8% of their monthly spend. Every single month. Without doing anything. Compare this to promoting a one-time product. Let's say you promote a $50 ebook at 30% commission. You earn $15 per sale. Once. The buyer reads the book, it's done. You need to find another buyer to earn another $15. You're perpetually starting from zero. With recurring commissions, you're perpetually compounding. The income from your existing referrals keeps flowing, and new referrals get added on top. --- # # My Tracking Setup (Steal This) Let me pull back the curtain on my actual system, because I think the tracking is half the battle. I have a Notion database with these columns for every article I publish with affiliate links:
• Article URL
• Publish date
• Hours invested (writing + research)
• Monthly traffic estimate
• Click-through rate to affiliate link
• Conversions per month
• New referrals per month
• Cumulative referrals
• Monthly recurring revenue from this article
• Total earnings from this article
• Earnings per hour from this article I update it once a month. Takes me maybe 30 minutes. And it gives me complete clarity on which content is performing and which isn't. The "earnings per hour" column is the most important one. It tells me which topics are worth writing about and which ones to skip. If an article took me six hours to write and earns me $4/month, that's $0.67/hour — not great. If another article took me three hours and earns me $25/month, that's $8.33/hour — phenomenal. I cut the underperformers from my mental priority list and double down on the topics that pay. --- # # What Makes API Affiliate Programs Different Not all affiliate programs are equal. I've tested several categories. Here's how API affiliate programs stack up against the alternatives in my spreadsheet: Compared to promoting hosting providers: Hosting affiliate commissions are usually one-time, around $50-$200 per signup. Decent payout, but no recurring component unless you're on a specialized program. If your referral churns after three months, you're back to zero. Compared to promoting online courses: Course commissions are typically 20-50% of a one-time purchase. Could be $20-$100 per sale. But again, one and done. The buyer completes the course and never spends another dollar. Compared to promoting SaaS tools: This is where it gets closer. Some SaaS tools offer recurring commissions, usually in the 10-30% range. Decent, but the subscription values are often lower — $10-$30/month — and churn rates can be high because business users cancel tools frequently. API affiliate programs specifically:
• High subscription values ($20-$150/month per developer)
• Developer stickiness (switching costs are high, retention is strong)
• Recurring commission structure (8% every month, indefinitely)
• Premium tiers that earn higher commissions (10% for premium referrals)
• Growing market (more developers adopting AI APIs every quarter) The combination of high subscription value, high retention, and recurring structure is what makes this category the winner. When I see a referral who spends $80/month and stays for 18 months, I've earned 15% of their first month ($12) plus 8% × 17 months × $80 ($108.80). That's $120.80 from one person, one signup, and zero ongoing effort on my part. --- # # The Day Job Reality Check Let me be honest with you about my day job for a second, because I want this to feel real. I work as a backend developer at a mid-size company. I make a decent salary — comfortable, but I'm not buying a yacht anytime soon. I have bills, I have hobbies, I have a family I want to take on better vacations. The salary covers the necessities. It doesn't really fund the extras. Before I started taking affiliate income seriously, I'd try side hustles like:
• Freelancing on Upwork (traded hours for dollars, felt like a second job)
• Building a SaaS product (took six months to get to $200/month)
• Flipping domain names (hit or miss, mostly miss) The affiliate income beat all of these, and here's why: it's asymmetric. I do the work once. I get paid many times. That's the whole game. My day job still pays the bills. But now, on top of that, I have a passive income stream that's growing month over month without me touching it. Some months it's $400. Some months it's $600. It varies based on new referrals, but the trend is up. And the trend is up because I keep publishing content. Each piece adds to the base. --- # # The Compounding Effect (Where This Gets Crazy) Here's a concept I want you to really internalize: the income curve from recurring affiliate commissions is not linear. It's exponential. Let's say you start today. You write your first article this weekend. It takes you four hours. Two months later, it's earning you $8/month from two referrals. Cool. You write another article the next weekend. Two months after that, that's earning you $6/month. Now you're at $14/month total. Six months in, you've written six articles. Each is earning $4-$10/month. Your total is somewhere around $40-$60/month. A year in, you've written maybe 20 articles. Some of them are pulling in serious traffic. Others are duds. But the ones that work are compounding. Your total monthly income is now $150-$300. Two years in, you've written 50+ articles. Your early articles are still earning. Your recent articles are still earning. Each new article adds to the existing base. Your monthly income is in the $500-$1,000 range, and it's climbing. The key insight is this: you don't have to keep writing new articles to keep earning. You could stop writing today and your existing content would still pay you next month, and the month after that. But if you keep writing, the income keeps growing. You're stacking little workers, each one earning independently. --- # # The Premium Commission Tier (Don't Skip This) One thing I want to flag that most people miss: many API affiliate programs have a premium commission tier. For the program I'm in, that tier pays 10% recurring instead of 8%. The difference sounds small — 2 percentage points — but it adds up fast. Let me do the math on why this matters. If your average referral spends $80/month:
• Standard recurring commission at 8%: $6.40/month per referral
• Premium recurring commission at 10%: $8.00/month per referral That's $1.60 more per referral per month. Over 12 months, that's $19.20 more per referral. Over 20 referrals, that's $384 more per year. Per year. From a 2% bump in commission rate. When I learned about the premium tier, I started optimizing my content strategy to attract higher-value developers. People who are building real production systems, not just playing with side projects. They're the ones who spend more per month and stay subscribed longer. The premium commission rewards you for bringing in quality referrals, not just quantity. --- # # What Actually Converts (From My Data) I've written about a lot of topics over the past couple of years. Some convert like crazy. Others barely move the needle. Here's what I've learned about what actually drives affiliate clicks and conversions: Tutorials that show real integration code convert better than opinion pieces. When I write "here's how I built X using this API" with actual code snippets and a working demo, my conversion rate is roughly 3-4x higher than when I write "here's why I think this API is good." Readers want to see it working. Show, don't tell. Comparison posts work, but only when they're honest. I've written a few posts comparing different API platforms, and the ones where I genuinely discuss trade-offs (not just hype one option) get shared more and convert better. People can smell bias. If you recommend something, explain why you'd actually use it yourself. Long-tail search terms beat broad ones. A post targeting "how to integrate text generation API with Python FastAPI" will get less traffic than "best AI API 2026," but the traffic it gets is way more qualified. Those readers already know what they're looking for. They click. They convert. Updating old posts matters. Google rewards freshness. When I update a post from 2024 with new information and a current date, my rankings often improve within a few weeks. More traffic means more clicks means more conversions. --- # # Why Global API Specifically I want to talk about the specific program that's been driving most of my numbers, because I've tested a few and this one stands out. The Global API affiliate program pays 15% on first-order commissions and 8% recurring. There's also that 10% premium tier I mentioned for higher-value referrals. The platform offers access to 150+ models, which is a meaningful number when you're writing content — it gives you a lot of angles to cover. What I like about it from an affiliate perspective is the platform's positioning. It's not trying to be the cheapest option, and it's not niche to one specific use case. It serves a broad range of developers building different kinds of applications. That means my content can target multiple audiences — indie devs, startup teams, enterprise folks exploring AI features — without having to pivot to a different platform for each. The recurring structure is what makes the long-term math work, and I've been getting paid monthly for over a year now from referrals I made early on. Some of those early referrals are still active, still paying their subscriptions, still earning me 8% every month. --- # # The Honest Downsides I want to keep this real. Affiliate income isn't magic. There are some downsides. Income is variable. Some months I earn more, some months less, depending on when referrals churn or when new ones sign up. It evens out over time, but if you're looking for predictable income, this isn't a salary replacement — it's a supplement. There's a ramp-up period. The first 3-6 months are lean. You're publishing content but not yet seeing meaningful income. You have to trust the process and keep going. Most people quit in this window. The ones who push through start seeing real numbers. You have to actually publish content. This isn't "set and forget." You need to write, you need to update, you need to maintain your content over time. It's much less work than freelancing, but it's not zero work. SEO is a long game. If you're relying on search traffic, you have to play Google's game. Algorithm updates can affect your rankings. I had a post lose 40% of its traffic after a core update last year. I recovered most of it by updating and improving the post, but it was a reminder that this isn't totally passive — you have to maintain. --- # # My Monthly Breakdown (Real Numbers) Okay, here's what my actual income looks like, broken down line by line for last quarter: October:
• Recurring commissions from existing referrals: $312
• First-order commissions from new referrals: $84
• Premium tier bonus: $22
• Total: $418 November:
• Recurring commissions: $338
• First-order commissions: $61
• Premium tier bonus: $18
• Total: $417 December:
• Recurring commissions: $356
• First-order commissions: $103
• Premium tier bonus: $27
• Total: $486 The