1 · Suppliers
Columns are matched by header name — name is required; email, category, contact, phone are picked up when present (aliases like “Vendor”, “Company” or “Contact Email” work). Import these before contracts: a contract is matched to its supplier by name.
2 · Contracts
supplier is required and must match a supplier already on file — a contract attached to the wrong vendor renews against the wrong company, so an unmatched name is reported rather than guessed. title, value, renewal_date, end_date, auto_renew are optional.