Polar Checkout Troubleshooting (2026 Edition)

Practical tips for signature, link ID, amount format (dollar vs cents), and webhook verification.

Plan resolution: Link ID first

Enterprise link: polar_cl_wZ44ubwBQIAmO4MlRfEbiBp66xaEj6kHcPr9V4N6H2g. Personal link: polar_cl_U6NSHAE9asvgsmOyXKbsDzCvwiqzYifgeP7Ei0MFDN0. If amount is 49 dollars, link ID still forces Enterprise.

Webhook vs Verify

If the webhook fails, the success page calls verify-checkout to update DB. Both paths set plan/limits identically.

Signature & secret

If POLAR_WEBHOOK_SECRET is missing, signature is skipped but logged. In production, always set the secret.

Environment checklist

Ensure SUPABASE_SERVICE_ROLE_KEY, NEXT_PUBLIC_SUPABASE_URL, POLAR_API_KEY, and POLAR_WEBHOOK_SECRET are set. Logs on success page show missing envs.