NextJS app pretty slow

React Project - Invalid environment variables: { DATABASE_URL: [ 'Required' ] }
npm run dev- I get some errors. I'm searching tutorials, docs e, and so on and so fort, but I did not get successful. Please, someone could please help me to find a solution to this trouble. Description ERROR bellow. Thanks in advance.
Best Atlassian alternative?
Error Management / Error Tracking tools/service for T3?
lint rule to ban anonymous functions inside HOCs
How to setup openAPI-TRPC for T3 project
Redux toolkit Presist Error

Can't get OG to show
HTML5 Video (h.265, mp4) looks pixelated/blurry in Chrome/Firefox:, but fine in Safari.
Alternative to Clerk for cross-platform app (Next.js / React Native + Expo)
~/components vs ~/components/Button
error with this prisma delete request?

Storing and retrieving cookie
switch image based on light and dark mode doesn't work well ?
Email Attachments without creating a file

Is there a framework for building cross-platform apps for Android, iOS, MacOS, and Windows?
Some domain philosophy
.com domain was already taken.
Here are my options right now;...dynamic unit testing
Why does vercel strip out authorization headers?
x-vercel-sc-headers. Googling for this is a bit overwhelming tbh, lots of different articles but no specific mention of that specific header key. Was wondering if someone could point me in the right direction to fix this quickly? Thanks!Migrating from Firebase to Supabase