v0 problems and how to fix them

Fixes for v0 projects deployed to Vercel that misbehave for visitors.

v0 preview doesn't match the deployed site: how to fix it
Your v0 preview looks right but the Vercel deployment has missing styles or a broken layout. Find the duplicate CSS, config or cache that causes it.
v0 "Application error: a client-side exception has occurred": the fix
Your deployed v0 app shows "Application error: a client-side exception has occurred". How to read the real error and fix the usual production causes.
How to change the "v0 App" title and "Created with v0" description
Your browser tab and Google result say "v0 App" and "Created with v0". How to set a real title, description, favicon and share preview in a v0 project.
Vercel site asks visitors to log in: why and how to make it public
People who open your link get a Log in to Vercel page instead of your site. Why Vercel Authentication does this and which link or setting fixes it.
v0 images not showing after deploy: the causes and fixes
Images show in the v0 preview but are broken on the live Vercel site. Check remotePatterns, file paths, letter case and temporary image URLs.
v0 contact form not sending email: what to check
Your v0 contact form says thanks, but no email arrives. The Resend key, from address and silent server action errors behind it, and how to fix them.