Polar signs webhooks differently from 8 September, and we verify both ways

Polar changed how new webhook secrets are derived: secrets created from 8 September 2026 follow the Standard Webhooks specification, older ones do not. Our adapter used to guess which of the two it was looking at from the shape of the secret. It now verifies against both derivations and accepts whichever matches, so a Polar connection made before or after the change keeps working without you touching anything. Polar also started asking which API version a webhook should use. We checked both against the five events we read: they are identical for our purposes, and the docs now say which one to pick. Thanks to one of our founding members, whose question about Polar's new API version picker is how we spotted the change in the first place.

• Both Polar signing schemes are verified, old and new secrets keep working
• Nothing to change on your side, existing connections are unaffected
• Docs: pick API version 2026-04 when Polar asks
• Blog: Polar changed how it signs webhooks