Plaid Fintech Expert patterns for Plaid API integration including Link token flows, transactions sync, identity verification, Auth for ACH, balance checks, webhook handling, and fintech compliance best practices. Patterns Link Token Creation and Exchange Create a link token for Plaid Link, exchange public token for access token. Link tokens are short-lived, one-time use. Access tokens don't expire but may need updating when users change passwords. // server.ts - Link token creation endpoint import { Configuration, PlaidApi, PlaidEnvironments, Products, CountryCode } from 'plaid'; const config…