Multi-tenant CRM

Build a production-ready multi-tenant CRM with strict tenant isolation, team memberships, role-based permissions, contacts, companies, pipelines, tasks, activity history, email workflows, reporting, and external API access. Define data boundaries for tenant-scoped records, integration credentials, event logs, and reporting aggregates. Include audit logs for record and permission changes, resilient processing for outbound email and integration jobs, observability for sync failures, rate limiting and access controls for public APIs, and a schema evolution strategy that preserves tenant data integrity and historical analytics.