Supabase Storage Deep Dive — Bucket Design, Signed URLs, Image Transforms, and RLS

Supabase Storage is S3-compatible object storage that integrates directly with PostgreSQL Row Level Security. It's not just a file bucket — it handles access control, on-the-fly image transformations, and CDN delivery all in one place.

Bucket Design

-- Public bucket: anyone can read via URL, no signature needed INSERT INTO storage . buckets ( id , name , public ) VALUES ( 'avatars' , 'avatars' , true );

-- Private bucket: requires a signed URL to read INSERT INTO storage .…