Analytics API

Analytics APIs:

• POST /v1/analytics/cashflow calculates annual cashflow from supplied finance data.
• POST /v1/analytics/spending-by-category calculates category totals from supplied transactions.
• GET /v1/me/analytics/cashflow?currency=INR loads authenticated user data through Supabase RLS and returns annual cashflow.
• GET /v1/me/analytics/spending-by-category loads authenticated user transactions through Supabase RLS and returns category totals.

Analytics APIs should prefer summaries and aggregated records.