How do backend systems integrate with databases, CRMs, and third-party tools?

Backend systems integrate with databases through an ORM (Object-Relational Mapper) like Prisma, Sequelize, or SQLAlchemy, which abstracts raw SQL queries into code-level data models that are safer, more readable, and easier to maintain. Database connections are pooled to manage concurrent requests efficiently without exhausting connection limits.

CRM integration uses the CRM’s REST API with OAuth 2.0 authentication, pushing contact records, deal updates, or activity logs from the website backend to Salesforce, HubSpot, or Zoho in real time or via scheduled batch sync. Third-party tool integration (payment gateways, SMS providers, shipping APIs, mapping services) follows the same pattern: server-side API calls using managed credentials, webhook listeners for asynchronous event confirmation, and error handling with retry logic for transient failures. All integrations should be documented in an integration registry that lists endpoints, authentication methods, data flows, and fallback behavior.