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Database / Supabase basics Interview Questions

What happens when a Postgres trigger fires on a table linked to Edge Function webhooks?

A database webhook is really just a trigger wired to fire on INSERT, UPDATE, or DELETE for a specific table; when the triggering statement commits, Postgres sends an HTTP POST containing the changed row's data (and, for updates, the previous values) to a configured URL, commonly an Edge Function endpoint.

The Edge Function then runs independently of the original database transaction — it receives the payload, executes its own logic (like charging a card or sending a notification email), and its outcome doesn't roll back the original insert even if the function itself fails. Because of that, the pattern is best suited to side effects that are acceptable to retry or handle asynchronously, and teams often add their own retry or dead-letter handling in the function rather than assuming delivery is guaranteed.

What does a database webhook send when its trigger fires?
If the Edge Function invoked by a webhook fails, what happens to the original database transaction?

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More Related questions...

What is Supabase? What is the purpose of PostgreSQL within Supabase? What are the core services offered by Supabase? What is Supabase Authentication used for? What are the types of storage available in Supabase Storage? Define Row Level Security in Supabase? Describe the Supabase client library? What is the purpose of Supabase Edge Functions? List the API types Supabase auto-generates from your schema? How do you create a new Supabase project and connect to it? How does Supabase auto-generate REST APIs from a database schema? Why is Row Level Security important in a client-facing Supabase app? How does Supabase Realtime broadcast database changes to clients? What is the difference between the anon key and the service role key in Supabase? When should you use an Edge Function instead of a Postgres database function? How do you troubleshoot a valid query being blocked by Row Level Security? What is the difference between using Supabase Auth and rolling your own JWT-based authentication? How is data validated before insertion in a Supabase table? Why do we use database migrations in Supabase projects? What happens when a Postgres trigger fires on a table linked to Edge Function webhooks? Explain the execution flow of a request through Supabase's auto-generated API? Why doesn't Supabase recommend using the service_role key on the client? How can you optimize Postgres connection pooling for serverless Edge Functions? Explain the internal working of Row Level Security policy evaluation in Postgres? What is the difference between pgvector similarity search and hybrid search in Supabase? Which is better for real-time collaboration, Supabase Realtime or client-side polling, and why? How does Supabase handle connection pooling for high-concurrency workloads? Explain the lifecycle of a Supabase Auth session token? When would you choose self-hosting Supabase over the managed cloud offering? How do you optimize full-text search performance on a large Postgres table in Supabase?
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Supabase Intermediate to Advanced Interview Questions

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