Most affiliate programs pay once and disappear. FCS API pays 30% recurring forever. That difference compounds fast when you're building fintech tools that stick around.
I've tested a dozen API affiliate programs. Most cap at 10-15%, some pay only first month. FCS keeps paying as long as your referral stays subscribed. If someone signs up for the $49/month plan, you get $14.70 every single month. That client stays two years? You made $352 from one signup.
The Math That Actually Works
You're already building. Currency converter for a SaaS dashboard. Forex widget for a trading blog. Crypto price ticker for a portfolio app. You need an API anyway — might as well get paid when users upgrade.
Let's say you embed a free currency converter on your site. Gets 2,000 monthly visitors. Conversion rate to paid plans sits around 0.5-1% if traffic is decent quality. That's 10-20 signups per month. Most pick the $49 or $99 plan. Low end: 10 signups × $49 × 30% = $147/month recurring. High end: 20 signups × $99 × 30% = $594/month recurring.
Year one you're at $1,764 to $7,128 annual recurring revenue from one integration. Year two that doubles because old referrals keep paying and new ones stack on top.
Where Developers Mess This Up
Biggest mistake: hiding the affiliate link like you're embarrassed. I've seen devs bury it in footer fine print or skip it entirely because "it looks spammy". Wrong energy. You solved a problem — forex data, crypto prices, exchange rates. If someone wants more calls or faster updates, they need a paid plan. That's the deal.
Put the upgrade path right in the UI. "Need real-time updates? Upgrade here." Direct. Clear. No guilt.
Second mistake: targeting the wrong projects. Personal hobby sites convert poorly. SaaS dashboards, fintech apps, trading platforms — those convert. Users already expect to pay for tools. They're not browsing for fun, they're solving business problems.
Passive Income That Isn't BS
I hate "passive income" talk because it's usually a lie. But this is the exception. You write the integration once. Maybe 3-4 hours of work for a clean currency converter or price widget. Then it runs. As long as your project stays live, referrals trickle in.
I built a forex calculator two years ago. Still gets 800 visitors monthly. Still converts 3-5 paid signups per month. That's $50-80 every month I don't think about. Multiply that across four projects and suddenly it's real money.
The recurring part matters more than the percentage. One-time commissions die fast. Recurring stacks. Month 12 you're collecting from 12 months of signups. Month 24 you're collecting from 24 months. The base keeps growing as long as churn stays low and you keep driving traffic.
What You Actually Need
A project with traffic. Doesn't need to be huge — 500-1,000 monthly visitors works if they're the right people. Fintech users, crypto traders, SaaS builders, developers working on financial tools.
An integration that makes sense. Don't force it. If you're building a recipe app, forex APIs don't fit. But if you're building anything touching money, prices, or international transactions — obvious fit.
Patience for the first 60 days. First month you get maybe 1-2 signups. Feels slow. Month two you get 3-4 plus the original ones still paying. Month six you're at 15-20 active referrals and momentum builds itself.
The 2026 Angle
Fintech APIs are having a moment. More indie devs building financial tools, more SaaS products need currency or crypto data, more platforms integrating live exchange rates. Demand is up and it's not slowing down.
FCS pricing is still reasonable compared to competitors. That matters because higher-priced APIs scare off smaller projects. You want referrals that convert, not ones that bounce at checkout. The $49-$99 sweet spot hits the right balance — affordable enough to convert, expensive enough that your 30% is worth it.
Plus the documentation is good. I've sent people to APIs with terrible docs and they give up halfway through integration. FCS forex API documentation and crypto API docs are clean. That means fewer support questions for you and higher completion rates on signups.
When It Doesn't Make Sense
If your project gets zero traffic, don't bother yet. Build the audience first. Affiliate revenue needs eyeballs.
If you're targeting non-technical users who won't upgrade, skip it. A blog about forex trading might drive traffic but readers won't pay for API access — they're not developers. You need users who actually need the API, not just the data.
If you hate the idea of monetizing, fine. But then don't complain about server costs eating your hobby project budget. Affiliates are the cleanest way to fund side projects without ads or selling data.
The 30% recurring commission is the hook. The real value is building something once and collecting for years. Most dev work pays once — client project, freelance gig, one-time sale. This pays monthly. That's the
