A concrete example
My site has a form that sends an email. Instead of managing a Node server, I write a function in /api/subscribe.js. Vercel handles the rest.
Why it matters
For 80% of cases (a simple API, a webhook, an AI integration), Vercel Functions replace a backend server with zero effort.
You'll run into it in /api folders, newsletter forms, webhooks, AI calls, and Vercel logs.
Don't mix it up with
Supabase Edge Function: A Supabase Edge Function runs server-side code to connect an app to APIs or handle a sensitive action.
Webhook: A webhook is a URL that gets called automatically when an event happens.
Common mistakes
- Putting long-running code in them (there's a timeout limit depending on your plan).
- Forgetting to set the environment variables on the Vercel side.
- Mixing up Vercel Functions (serverless) and Edge Functions (a different runtime).
Quick checklist
- First I check whether the word names a concept, a tool, a risk, or a metric.
- I tie it to a concrete case: My site has a form that sends an email. Instead of managing a Node server, I write a function in /api/subscribe.js. Vercel handles the rest.
- I keep the main trap in mind: Putting long-running code in them (there's a timeout limit depending on your plan).
Quick questions
What is Vercel Function in AI?
A Vercel Function runs server code without you having to manage a server yourself.
Where will I run into Vercel Function?
You'll run into it in /api folders, newsletter forms, webhooks, AI calls, and Vercel logs.
Which word should I read next?
Start with Supabase Edge Function, Webhook, API key.