Cookbook

Short patterns you can lift whole: each recipe is a page of prose around a runnable snippet, exercised in CI exactly as shown.

• A promo with an expiry

  Grant marketing credit that spends first and claws itself back when the deadline passes.

• An entitlement-gated feature

  Sell a SKU once, gate access on read.entitled, and revoke it when the money comes back.

• A marketplace fee split

  One sale, several sellers: the fee off the top, shares in basis points, no unclaimed remainder.

• Scheduled top-ups

  A recurring allowance from any timer, made safe by minting the idempotency key from the period.