How to improve email deliverability on Supabase, the default sender trap explained

PSA because this catches someone here every week.

if your Supabase emails are landing in spam or not arriving, the cause is usually one of these, in order:

you're still on the built-in default sender for real traffic. it's testing-only, low limits, no reputation. move off it first, this is most cases.

your domain isn't authenticated. no SPF/DKIM/DMARC is an automatic spam flag no provider can fix for you.

fresh domain, no warmup, sudden big send. looks identical to spam to gmail.

receipts and marketing sharing one reputation, so a bad campaign drags your auth emails down.

fix those before you blame your provider or switch tools. i switched once before fixing DNS and it changed nothing.

what was your actual fix? curious how often it's just the default sender.