Let’s clear up the name first: this guide is about Polar.sh, the open-source merchant of record that indie developers keep moving their billing to, not Polar the watch company. Nobody here is earning commissions on heart-rate straps.
I build affiliate software (Rekomi), and we just shipped native Polar support, so I’ve spent more time in Polar’s webhook reference lately than in my own inbox. This is the write-up I wish had existed when we started: why a Polar affiliate program is such a natural fit, the three real ways to run one, what the setup looks like, and how tracking should behave on a merchant of record, where tax rides inside every single charge.
It’s an interesting moment to want this. Polar doesn’t ship an affiliate feature of its own, and most affiliate platforms haven’t caught up to it yet, so the field is small and moving fast.
Why affiliates fit Polar.sh sellers so well
Affiliates fit Polar sellers because the products are digital, the margins are high, and the merchant of record model already handles the messiest part of selling globally: tax. Polar is the legal seller on every transaction, so it calculates, collects, and remits VAT and sales tax for you, whether the customer is in Berlin or Boise. That means an affiliate can send you buyers from anywhere and the compliance side of the sale just works.
The economics are the other half. A commission-per-sale program only costs you money when it makes you money: you offer a percentage, and you pay it after a sale actually lands. Across programs running on Rekomi, most SaaS offers settle between 20% and 30%. And because so much of what sells on Polar is subscription software, those commissions recur. A developer who refers ten customers to your $29/mo tool at 25% is building roughly $72/mo of income that renews itself, which is exactly the kind of math that keeps good affiliates promoting you for years.
Three routes to a Polar affiliate program
You have three realistic options today, and they scale in effort and completeness.
1. Build it yourself on Polar’s webhooks. Polar’s API is genuinely good, and everything you’d need exists: subscribe to order.paid, stamp an affiliate code into checkout metadata, and record commissions as events arrive. If you’re an engineer, the prototype is a weekend. The catch is everything after the prototype: refund clawbacks, an affiliate dashboard, link management, payouts, and tax forms for the people you pay. You end up maintaining a second product next to the one you’re trying to sell. It’s a rational choice for a very specific founder; for most, the weekend turns into a quarter.
2. Use one of the Polar micro-tools. Credit where it’s due: a handful of tiny teams (Affonso, Refgrow, Sled) shipped Polar support before almost any of the big platforms did, and Dub still lists its Polar integration as coming soon. That’s a genuinely impressive bit of hustle from small builders. The trade-off is scope: these tools mostly stop at tracking and a dashboard, so paying affiliates and handling their tax paperwork stays a manual job on your plate.
3. Run it on a full platform with a native Polar integration. This is the lane Rekomi is in: the Polar integration covers tracking, and the platform around it covers affiliate payouts and tax forms, so the whole program lives in one place. If you’re still mapping the broader field of dedicated platforms, my guide to affiliate tracking software walks through what separates the tiers.
Worth noting how Polar’s peers differ here: Lemon Squeezy ships a built-in affiliate hub, which changes the whole decision (I walked that math in my Lemon Squeezy guide). Polar keeps its core focused and leaves affiliates to the ecosystem, which I think is the right call for an open-source MoR: it does the merchant-of-record job extremely well and lets specialists do this one.
The setup: one token and about ten minutes
The whole connection runs on a single credential. In Polar, under Organization Settings and then Developers, you create one Organization Access Token with exactly two scopes: organizations:read and webhooks:write. Set the expiration to “No expiration” so the connection never lapses on a timer, then paste the token into Rekomi.
From there, Rekomi does the plumbing itself: it validates the token, resolves your organization, and creates the webhook endpoint in your Polar account on its own, subscribed to the order, subscription, and refund events it needs. Polar generates the signing secret when the endpoint is created, and Rekomi stores it encrypted and verifies the signature on every delivery. You never touch a webhook screen!
Attribution has two paths, and you only need the one that matches how you sell:
- API checkouts: stamp
metadata.rekomi_refon the checkout usingwindow.Rekomi.getReferral()from the tracking script, and the referral rides through to the order. - Shareable checkout links: append
?reference_id=CODEto the link. Polar copies it into the order’s metadata, where Rekomi reads it as the secondary key. I love this path: it’s an affiliate link that works with zero code on your side.
The click-by-click version of all of this, with screenshots, lives in the Polar install doc.
What gets tracked, and what deliberately doesn’t
Orders and renewals both flow in through order.paid, so an affiliate’s recurring commissions accrue automatically as their referred subscriptions renew. Refunds and chargebacks arrive through the same pipe: a full refund claws back the whole commission, a partial refund claws back proportionally, and both land in the same audit trail as the original conversion. If a customer gets 30% of an order back, the commission drops by exactly 30%, with no spreadsheet involved.
Now the part I find most interesting: what the commission is calculated on. On a merchant of record, the number on the customer’s card statement is not your revenue. Polar collects tax inside the charge and remits it to governments on your behalf, so an order total is an iceberg: your price is the visible part, and the tax underneath was never yours.
The math: say you sell a $29/mo tool and a customer in Germany subscribes. With 19% VAT, their card is charged $34.51. Your revenue is $29; the $5.51 is tax Polar remits for you. At a 25% commission, the right payout is $7.25. Calculated naively on the charged total, it would be $8.63, which means paying $1.38 every month, per customer, out of money you never received. At 100 referred customers, that’s about $138/mo of pure overpayment. So Rekomi computes commissions on the pre-tax net amount: after discounts, excluding tax, and net of any customer-balance credit Polar applied. If an affiliate platform pays commission on the tax line, that’s a bug, not generosity.
One more deliberate choice: free trials. Polar emits a $0 order when a trial starts, and that order never earns commission. When the referral is attributed, Rekomi records it as a $0 lead (visible in your funnel and leads views), and the commission comes from the first real charge. Affiliates get paid on actual revenue, and you never have to claw back a commission for a trial that quietly evaporated on day 13.
Where Rekomi fits. Rekomi is the tracking layer and the money layer in one: affiliate signup pages and first-party tracking on the front end, then Stripe-powered payouts and tax forms when commissions come due. Plans start at $29/mo plus 3% of what your affiliates earn, with a 14-day free trial, and the Polar integration is included on every plan. The honest trade-off: because the 3% scales with payouts, a program moving serious commission volume pays Rekomi more than it would pay a flat-fee micro-tool; you’re trading that for never running a payout or a tax form by hand. The full breakdown is on the pricing page.
Polar affiliate program FAQ
Does Polar.sh come with affiliate tracking built in?
No. Polar handles payments, global tax, subscriptions, and license keys as a merchant of record, but it doesn’t ship affiliate tracking the way Lemon Squeezy does. To run an affiliate program on Polar, you connect an external tool or build on Polar’s webhooks yourself.
How do affiliates get credited on a Polar checkout link?
Append ?reference_id=CODE to the checkout link, where the code identifies the affiliate. Polar copies the value into the order’s metadata, and the tracking platform reads it from there. API-created checkouts can stamp metadata.rekomi_ref directly instead.
Do Polar affiliate commissions include VAT or sales tax?
No, and they shouldn’t. Polar collects tax inside each charge and remits it for you, so that money is never your revenue. Commissions should be computed on the pre-tax net amount: after discounts, excluding tax, and net of applied customer credit.
How do refunds affect Polar affiliate commissions?
They’re clawed back automatically. Full refunds reverse the whole commission, partial refunds reverse it proportionally, and chargebacks flow through the same refund events, so the affiliate’s balance always matches what you actually kept.
Does a free trial signup earn a commission?
No. A trial start is a $0 order, and it never earns commission; when the referral is attributed, Rekomi records it as a $0 lead. The commission is recorded when the trial converts and the first real payment succeeds, so affiliates earn on revenue, not signups.
Your next 15 minutes
If you sell on Polar, the best 15 minutes you’ll spend this week is creating that Organization Access Token: two scopes, no expiration, one paste. The install doc walks the rest, and with Rekomi’s 14-day free trial the experiment costs you nothing but the setup time. Almost nobody in the affiliate space supports Polar natively yet, which means the sellers who launch a Polar.sh affiliate motion now get first pick of the affiliates who love promoting indie software. That window won’t stay open forever, so grab it while it’s quiet.
