Where each is relatively distinctive
Supabase is relatively distinctive when PostgreSQL, SQL workflows and a larger ecosystem are central to the product. PocketBase is relatively notable for packaging a small backend around SQLite, authentication, files and an admin UI. Appwrite is relatively broad as a self-hostable backend platform with multiple services. These are differences in operating shape, not a claim that one is better.
Where each fits
Consider Supabase for products that benefit from relational data and SQL familiarity. Consider PocketBase for a small, self-contained application where a compact deployment is part of the design. Consider Appwrite when the team wants a service-oriented backend surface and is willing to operate more pieces. Make the choice from actual data relationships, access patterns and recovery requirements.
Boundaries and ownership
Managed and self-hosted offerings have different responsibilities. Read the production warnings, migration notes, backup guidance and service-specific license terms before putting important data into a system. Authentication, file storage and database recovery should be tested together; a successful first login is not a production readiness check.
A comparison you can run
Build the same small feature three times: two related records, one sign-in flow, one file upload, one permission rule and one backup/restore cycle. Record setup steps, restore steps, logs, migration effort and recurring infrastructure cost. Publish the observations with dates so later readers can distinguish documentation from your own test.