Why Your Supabase App Might Be Leaking User Data (and How to Fix It with RLS)

So you vibecoded an app, pushed it live, and it's getting real users. Congrats — that's genuinely exciting. But here's a question worth pausing on: Can your users read each other's data? If you're using Supabase and haven't thought carefully about Row Level Security (RLS), the honest answer might be yes—and that’s a serious problem. Exposing user data doesn’t just break trust; it can also violate privacy regulations, leading to fines and reputational damage. This article breaks down what RLS is, why it matters, how it can get misconfigured, and how to fix it — without a security engineering background. ** First, a Quick Bit of Context ** Supabase is a Backend-as-a-Service (BaaS) platform built on top of PostgreSQL, one of the world's most popular open-source relational databases. Think of Supabase as Firebase, but open-source and SQL-native. It gives you a database, authentication, file storage, and cloud functions — all in one place. The key thing that makes Supabase different from a