When order webhooks arrive twice
How idempotency keys and reconciliation windows stop duplicate fulfillments after a payment provider retries a callback.
Field notes
Practical write-ups from integration assessments and connector design work.
Stock holds that survive a flash sale
Reservation windows, soft locks, and why pulling inventory every thirty seconds still oversells limited SKUs.
Mapping categories for Shopee-style feeds
Category trees, mandatory attributes, and keeping one catalog without drowning merchandisers in duplicate fields.
Tax hooks across cross-border carts
Where tax calculation belongs in the checkout sequence when you sell from Taiwan to nearby markets.