Connect Polar

Why Polar

Same idea as Paddle — Polar is the merchant of record, so sales tax and VAT are its problem, not yours — at roughly 4% + 40¢, and with the least friction to get started of the three merchant-of-record options.

It is built for developers selling digital products, so it also handles licence keys and usage billing natively.

Where to get the three values

Polar organization access token — polar.sh → Settings → Developers → New token. It needs two scopes: products:write and checkout_links:write. Copy it when it is shown; Polar will not show it again.

Polar organization id — polar.sh → Settings, directly under your organization name.

Polar webhook secret — polar.sh → Settings → Webhooks → add an endpoint pointing at the webhook URL kitty gives you (see below). Set the format to Raw, not Discord or Slack. Then copy the secret it generates.

As with Paddle, the least fiddly order is: connect with the token and org id, copy the webhook URL from the card, add the endpoint in Polar, then Replace keys with the secret filled in.

Connecting

Settings → Connections → Take payments → the Polar card → Connect → fill the fields → Save and connect. Then Test connection, which comes back naming your Polar organization.

The webhook, which is not optional

kitty needs Polar to tell it when someone pays. Without that, the checkout takes the money and no order, customer or revenue figure ever appears in kitty.

On the connected card, press Webhook URL, copy it, and paste it into polar.sh → Settings → Webhooks as a new endpoint, with format set to Raw.

Treat that URL like a password — anyone holding it can post events at this venture. It never expires; you rotate it by disconnecting and reconnecting. Deliveries are capped at 300 a minute per venture.

What you get

One-off sales and subscriptions, sales tax handled, and a reusable checkout link — so a buy button on your published site points straight at Polar with no extra hop.

Refunds are issued from Polar's own dashboard rather than from kitty, and kitty records them when Polar reports them.

After it's connected

Test connection proves the key works right now, and names the account it reached — so a member with two logins can see they pasted the wrong one. Do that before you put anything on sale.

Then, in Where new checkouts go, pick this provider on its own or One page, every method, which offers every provider you've connected on a single page and quietly hides one that starts failing.

Anything already on sale keeps the provider it was armed on. A price, once created at a provider, cannot be moved — so to switch, open the venture's Revenue tab, Take off sale, then put it back on sale.

How the keys are stored

Encrypted at rest with AES-256-GCM, used server-side only, never returned to the browser, never written to a log, and never shown again after saving.

Payment keys are scoped to a venture or the whole workspace, never to you personally — two businesses in one workspace settle into two different bank accounts, so a personal key is refused for money on purpose.