Double capture is the tax disconnected systems charge daily: same order in the website and the accounting tool, same client in the CRM and the spreadsheet. Integration removes the tax — if designed properly.
Step 1: Map the real flows
Before any code, map what data moves where, which system is the source of truth for each record type, and what happens on conflict. Most integration failures are mapping failures wearing technical clothes.
Step 2: Choose the right pattern
Real-time webhooks for events that matter now (payments, bookings). Scheduled sync for reference data (products, price lists). APIs for on-demand lookups. File imports only where vendors leave no choice — and with validation, not blind trust.
Step 3: Design failure loudly
Every integration fails eventually — vendor downtime, changed APIs, bad data. Proper design retries transient failures, quarantines bad records visibly, alerts humans, and never silently drops transactions. Silent failure is a design flaw, not bad luck.
Step 4: Plan for vendor change
Vendors version, deprecate and reprice APIs. Budget maintenance for integrations like any living system, and keep credentials, mappings and runbooks documented — not in one person's head.