Harden Startup Multi-Tenant Security

Right now our young Fintech SaaS platform shares a Postgres database across all customers, and the current tenancy filter lives only in middleware. We have no live clients. Before we do, we need airtight,... (Budget: min $50 USD, Jobs: Data Mining, Database Programming, FinTech, Link Building, PostgreSQL, Python, SaaS, Security, Software Architecture, Software Development)