> Polar: what your AI agent should know — from The Handover, the-handover.org/services/polar
> © Captivated Ltd — free to use in your own work, not to redistribute as a collection. the-handover.org/licence

# Polar

What we tell an AI agent working on a project that uses Polar: 2 rules, 2 learned the hard way.

Build a full rootnote set for a Polar project: https://the-handover.org/build?areas=working-agreement,payments,licensing&payments=polar&licensing=polar

The vendor's own file for agents (what Polar is, where its documentation lives): https://docs.polar.sh/llms.txt. This page covers where it catches agents out.

## Polar for payments

### Check a merchant of record's acceptable-use policy against what the product does, before building

> Hard-won · Leon Mallett (captivated.online) with Claude Code · reviewed 2026-10-19

- **Read the restricted-categories list before any integration work**, and judge
  it against what the product actually does — not against what kind of company
  you are.
- Legitimate software was rejected or banned here more than once **after
  integration had started**: automated social posting, AI-generated video, and a
  directory carrying advertising each fell foul of a policy written with
  something else in mind. Weeks of work were lost each time.
- **Where anything is close, ask the provider in writing first.** An approval
  given at onboarding is not the same as one given for the feature that ships.

### Polar's sandbox does not enforce the eligibility gate, and its signatures deviate from the spec they cite

> Hard-won · Leon Mallett (captivated.online) with Claude Code · reviewed 2026-10-15

Three things cost real time here, and none is in the documentation:

- **An eligibility gate the sandbox does not enforce.** Flows that pass in
  sandbox fail in production, so sandbox success is not evidence.
- **A signature scheme that deviates from the spec it cites.** Implementing the
  referenced standard faithfully produces rejected webhooks.
- **Webhook orderings that zero out an active subscription** if handlers assume
  arrival order.

Treat sandbox agreement as a necessary condition and never a sufficient one, and
make handlers order-independent rather than ordering-tolerant.

Full account: https://the-handover.org/docs/polar-billing-webhooks.md

## Polar for licensing

Also applies to every licensing choice, so not repeated here: Revoke a licence when what was paid for ends, never when the customer cancels; A licence check must never lock out somebody who paid.