Different philosophies
Supabase is built around Postgres, SQL, auth, storage, edge functions and now stronger MCP/agent connector scenarios. Convex offers a TypeScript-first reactive backend where queries, mutations and realtime UI naturally live together. Both are good, but they reduce different product risks.
When Supabase fits
Supabase often wins when a team needs the Postgres ecosystem, SQL control, migrations, BI integrations and clear links to familiar tools. In the AI context, MCP and Claude connector work make it convenient for agents that need to manage databases and edge functions through safe tools.
When Convex fits
Convex fits when the priority is quickly building a reactive product: dashboards, live agent states, collaboration, internal tools and AI assistant history. The WebEdge position is simple: choose Supabase when Postgres is the core of the data model; choose Convex when product speed depends on realtime state and a TypeScript workflow.