If you build SaaS and you have looked at billing options lately, Polar keeps coming up: open source, developer-first, and it handles the part most founders dread, global sales tax. But the pricing changed in 2026, and "open source" means something more specific than you might think. Here is an honest review of what Polar actually is, what it costs now, and who it fits.
What Polar actually is
Polar is a Merchant of Record (MoR) billing platform aimed at developers. The merchant-of-record part is the whole pitch: Polar becomes the legal reseller of your product, which means Polar takes on liability for sales tax, EU VAT, Canadian GST and the rest, registers in the relevant jurisdictions, and files and remits on your behalf. You stop worrying about tax compliance in dozens of countries; Polar worries about it and takes a cut.
Under the hood, Polar is built on Stripe as the underlying processor, with more planned. And it is genuinely open source: the full platform is on GitHub under the Apache 2.0 license, sitting around 10,000 stars as of mid-2026.
One honest caveat on "self-hostable": the code is open, but you cannot be your own Merchant of Record by running it. The MoR and tax entity is Polar itself. So treat "open source" as transparency and extensibility, not "run your own billing company over a weekend."
Pricing in 2026 (this changed)
This is the part most older reviews get wrong. Polar used to be 4% + 40 cents, which undercut Paddle and Lemon Squeezy. In 2026 Polar restructured its pricing. The free Starter plan is now 5% + 50 cents, the same headline as Paddle. The old rate survives only as a grandfathered "Early Member" price for organizations created before late May 2026, and it is lost the moment you upgrade to a paid plan.
| Plan | Monthly | Per transaction |
|---|---|---|
| Starter | Free | 5% + 50c |
| Pro | $20 | 3.8% + 40c |
| Growth | $100 | 3.6% + 35c |
| Scale | $400 | 3.4% + 30c |
On top of that: +1.5% on international (non-US) cards, $15 per dispute regardless of outcome, and Stripe-charged payout fees passed through. Transaction fees are non-refundable when you refund a customer. Source: Polar's fees page.
The takeaway: Polar's old price advantage over other Merchants of Record is mostly gone for new users unless you pay a monthly tier to buy the rate down. You now pay roughly the same 5%-ish all-in that any MoR charges, in exchange for not handling tax yourself.
Who is behind it
Polar was founded by Birk Jernstrom, a former Shopify director who previously built Tictail (acquired by Shopify). The company is based in Stockholm, shipped its first public version in 2023 and v1.0 in late 2024, and raised a $10M seed led by Accel in June 2025, with angels including the founders of Vercel, Supabase, Shopify, Resend and Raycast. At the seed it reported 17,000+ signups and triple-digit month-over-month revenue growth. So: young, but credible and well-backed.
Polar leans hard into developer experience: SDKs, framework adapters, and a "6-line integration" pitch.
Features for SaaS
Polar is more than checkout. From its docs, you get subscriptions and one-time products, usage-based and metered billing (ingest events, define meters, bill on the next invoice), license keys, large file downloads, and automated benefits like granting GitHub repo access or Discord roles on purchase. There is a hosted checkout, a self-serve customer portal, webhooks, and well-regarded SDKs with framework adapters. For an indie developer, the developer experience is a real selling point.
Failed payments: Polar handles dunning for you
Here is something many Merchants of Record do that raw Stripe does not: Polar runs automatic dunning for you. When a renewal fails, the subscription moves to past_due and Polar retries on a fixed schedule, 4 attempts over 21 days (roughly day 2, 7, 14 and 21). It emails the customer a link to the portal to update their card, and a successful update triggers an immediate retry. If all four attempts fail, or the card returns a permanent decline, Polar stops and cancels the subscription, revoking benefits.
This is genuinely useful, with one trade-off worth understanding: because Polar is the Merchant of Record, Polar owns the recovery flow. You cannot configure the retry cadence, change the emails, or bolt on your own multi-channel dunning. Your only levers are a grace-period setting and manual actions. That is the opposite of a raw Stripe setup, where you own retries entirely and can layer a dedicated recovery tool on top.
Worth saying plainly: on Polar you get hands-off, fixed dunning you do not control. On a processor where you own the payment relationship, like Stripe, Paddle or Square, recovery is yours to optimize, which is where a tool like Rebounce fits (it connects to Stripe, Paddle and Square, not Polar). To understand the mechanics either way, see what dunning is and why involuntary churn matters.
Polar vs Stripe, honestly
| Dimension | Polar | Stripe |
|---|---|---|
| Model | Merchant of Record | Payment processor |
| Sales tax / VAT | Polar files and remits | You handle it |
| Headline fee | 5% + 50c (tax included) | 2.9% + 30c (tax not included) |
| Dunning | Built in, fixed, Polar-controlled | You own it (Smart Retries + tools) |
| Integration | Open source, fast adapters | Broader, deeper, more mature |
Polar trades a higher headline fee and less control for removing global tax compliance. Stripe is cheaper per transaction and fully controllable, but pushes tax and recovery onto you. Neither is strictly better, it depends on how much you value not dealing with VAT.
So, is open-source billing worth it?
Polar is worth a serious look if you are a developer or small SaaS selling globally, you want tax compliance handled, and you value a clean open-source integration. It is less compelling purely on price now that the free tier is 5% + 50 cents, and the MoR model means you give up control over the payment relationship and the dunning flow. If you are comparing Merchants of Record more broadly, our Stripe vs Lemon Squeezy vs Paddle guide and the how to choose a payment provider post cover the wider field. And if you are weighing Dodo, another young MoR, see our Dodo Payments review.