Question 1

How does Supabase differ from Firebase?

Accepted Answer

Supabase is a Firebase alternative with PostgreSQL (not Firestore documents). Key differences: Supabase gives you SQL access and portability (you own your schema), Firebase locks you into Firestore. Supabase: better for complex queries, relational data, self-hosting. Firebase: better for real-time collaboration, simpler onboarding. Pricing: Supabase charges per project; Firebase charges per read/write. For data-heavy apps with complex relationships, Supabase wins.

Question 2

What is Row Level Security (RLS) and why is it critical?

Accepted Answer

RLS lets you define fine-grained database-level permissions using PostgreSQL policies. Instead of filtering data in the app layer (security risk), RLS enforces rules at the database: `CREATE POLICY user_read ON profiles FOR SELECT USING (auth.uid() = user_id)`. This means even if a hacker bypasses your app, the database won't expose other users' data. Pitfall: forgetting to enable RLS = entire table publicly readable. Always enable RLS first, then add `USING` clauses for SELECT/UPDATE/DELETE.

Question 3

Is Supabase vendor lock-in a risk?

Accepted Answer

Less than Firebase. Supabase runs on standard PostgreSQL, so you can self-host or migrate to any Postgres provider (AWS RDS, Heroku, DigitalOcean). The lock-in is around Supabase-specific features (Auth, Storage, Edge Functions), but the core data is portable. For migrations, export your schema and data, spin up PostgreSQL elsewhere. Self-hosting Supabase (via Docker) is possible but requires DevOps overhead. For most indie/startup projects, the trade-off (convenience vs portability) favors staying with Supabase.

Question 4

How do I scale PostgreSQL with Supabase?

Accepted Answer

PostgreSQL can handle millions of rows, but you need indexing. Index frequently-filtered columns: `CREATE INDEX ON profiles(email, created_at)`. Supabase includes monitoring (slow queries, disk usage). For horizontal scaling (sharding), Postgres is harder than document DBs — Supabase doesn't do auto-sharding. For massive scale (>100M rows, high concurrency), consider PgBouncer connection pooling (Supabase includes this), or move to specialized solutions (Citus, TimescaleDB). Most apps hit a ceiling at DB design, not Postgres limits.

Question 5

Should I use Edge Functions or Vercel Functions for server logic?

Accepted Answer

Both work, but Edge Functions (Deno runtime) are faster because they run globally, closer to users (<50ms latency). Vercel Functions run in a single region. Edge Functions are cheaper (faster response = lower compute). Trade-off: Edge Functions have no Node.js APIs, no native modules (harder for complex tasks). Vercel Functions give you full Node.js access but higher latency. Pattern: use Edge Functions for auth/redirects/simple transforms, Vercel Functions for heavy compute/database work, Supabase Database Functions (PL/pgSQL) for SQL-heavy logic.

Question 6

What are Supabase Auth providers and how do I set them up?

Accepted Answer

Supabase Auth supports email/password, magic links, OAuth (Google, GitHub, Discord, Twitter, LinkedIn). Setup: enable provider in Supabase dashboard, add OAuth app credentials (Client ID + Secret from Google/GitHub), configure redirect URLs (localhost:3000, production domain). In code: `supabase.auth.signInWithOAuth({ provider: 'google' })`. Supabase handles the callback. MFA (multi-factor) available but not required. For passwordless flows, magic links + email verification are secure and user-friendly.

Question 7

How do I handle file uploads and storage?

Accepted Answer

Supabase Storage (S3-compatible) is separate from the database. Upload via client or server: `supabase.storage.from('bucket-name').upload('file.pdf', file)`. Access with signed URLs (time-limited, private by default). Use RLS policies on storage buckets to control read/write. Pitfall: uploading directly from browser without size limits = expensive. Validate file types + sizes on client before uploading. For large files (>100MB), use resumable uploads or multipart.

Region	Junior	Mid	Senior
USA	$95k	$140k	$180k
UK	£65k	£90k	£120k
EU	€70k	€100k	€135k
CANADA	C$105k	C$155k	C$200k

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