# vercel

A Cursor rule with opinionated guidance for building and deploying on Vercel. Useful when your agent writes Next.js code and you want it to follow the platform's conventions.

- rule · `type=rule` · Cursor · ★ 3579
- Author: sanjeed5
- License: CC0-1.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/sanjeed5/awesome-cursor-rules-mdc/tree/HEAD/rules-mdc/vercel.mdc
- Updated: 2026-05-19
- HTML: https://affpapa.org/en/nevibecode/rules/vercel

## What it does

The `.cursor/rules/vercel.mdc` file loads into Cursor as a standing instruction for the agent: how to lay out serverless functions, what to do with a monorepo, where to turn on the Edge Runtime. It also names anti-patterns — server logic living outside `api/`, heavy libraries inside a function that push cold starts up.

Inside are sections on project structure, common patterns and performance. Code samples come in bad/good pairs: where `api/products.js` belongs, how to wire Turborepo for build caching, when to set `output: 'export'` for a purely static site. Caching via `Cache-Control` and the Next.js `Image` component get their own parts.

The rule is tied to Vercel and its conventions, so advice about Edge Runtime and Fluid Compute does nothing for a project hosted elsewhere. The text cuts off partway through the image optimization section.

## Install

### Cursor (native platform)

**Manually: put the files in place**
- File: `.cursor/rules/vercel.mdc` — Frontmatter: description, globs, alwaysApply

### Claude Code

**Manually: put the files in place**
- File: `.claude/rules/vercel.md` — The paths frontmatter field limits the files: move globs from the source into paths

### Codex

**AGENTS.md**
- Codex reads AGENTS.md: paste the rule text there

### GitHub Copilot

**Manually: put the files in place**
- File: `.github/instructions/vercel.instructions.md` — The applyTo field sets which files it applies to: move globs from the source into applyTo

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/rules/vercel.md`

### Cline

**Manually: put the files in place**
- File: `.clinerules/vercel.md`

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/sanjeed5/awesome-cursor-rules-mdc/tree/HEAD/rules-mdc/vercel.mdc

## When to use it
- keep serverless functions in `api/` instead of scattered files
- enable build caching in a monorepo with Turborepo
- switch a static site to `output: 'export'` and drop serverless overhead
- shrink a function bundle to cut cold start time
- set `Cache-Control` on data that never changes

## Example prompts
- Check this project against the vercel rule: serverless functions belong in `api/` or `app/api`
- Set up Turborepo for the monorepo the way the vercel rule describes
- Add `Cache-Control` to this API route following the vercel rule

## Source text · vercel.mdc · CC0-1.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: d7254f145b0e5aef.

BEGIN THIRD-PARTY FILE d7254f145b0e5aef
````text
---
description: This guide outlines definitive best practices for developing and deploying applications on Vercel, ensuring optimal performance, security, and cost-efficiency.
globs: **/*
---
# vercel Best Practices

Vercel is the definitive platform for deploying modern web applications, especially those built with Next.js. To maximize its potential, adhere to these opinionated guidelines for performance, security, and maintainability.

## 1. Code Organization & Structure

Organize your project to leverage Vercel's serverless functions and build optimizations.

### 1.1. Serverless Functions in `api/`

All serverless functions must reside within the `api/` directory (or `app/api` for App Router). This is Vercel's convention for automatic API route detection.

❌ **BAD: Mixing serverless logic outside `api/`**
```javascript
// pages/products.js
export default function Products() {
  // ... client-side logic
}

// In some_utility.js
export async function fetchProductsData() {
  // This function contains server-side logic and heavy dependencies
  // but is not in a dedicated serverless function file.
  const data = await expensiveDatabaseCall();
  return data;
}
```

✅ **GOOD: Centralized serverless functions**
```javascript
// pages/products.js (or app/products/page.tsx)
import useSWR from 'swr';

export default function Products() {
  const { data, error } = useSWR('/api/products', fetcher);
  // ... client-side rendering
}

// api/products.js (or app/api/products/route.ts)
import { NextResponse } from 'next/server';
import { expensiveDatabaseCall } from '@/lib/db'; // Separate DB logic

export const runtime = 'edge'; // Use Edge Runtime for speed

export async function GET() {
  try {
    const data = await expensiveDatabaseCall();
    return NextResponse.json(data);
  } catch (error) {
    return NextResponse.json({ error: 'Failed to fetch products' }, { status: 500 });
  }
}
```

### 1.2. Monorepo Caching with Turborepo

For monorepos, always integrate Turborepo to enable intelligent caching and prevent redundant builds. Vercel automatically detects and optimizes for Turborepo.

❌ **BAD: Monorepo without Turborepo caching**
```bash
# In a large monorepo, every Vercel build will re-build all packages
# even if only one has changed.
npm run build # Rebuilds everything
```

✅ **GOOD: Turborepo for efficient builds**
```json
// package.json (root)
{
  "name": "my-monorepo",
  "private": true,
  "workspaces": ["apps/*", "packages/*"],
  "scripts": {
    "build": "turbo run build",
    "dev": "turbo run dev --parallel"
  },
  "devDependencies": {
    "turbo": "latest"
  }
}
```

## 2. Common Patterns & Anti-patterns

Leverage Vercel's strengths, particularly Edge Functions and Fluid Compute, while avoiding common performance traps.

### 2.1. Prefer Edge Runtime & Fluid Compute

For serverless functions, prioritize the Edge Runtime and ensure Fluid Compute is enabled for automatic cold start optimizations and cost efficiency.

❌ **BAD: Default Node.js runtime for latency-sensitive functions**
```javascript
// api/heavy-computation.js
// This will run in a traditional Node.js Lambda, potentially incurring cold starts.
export default async function handler(req, res) {
  // ... heavy logic
}
```

✅ **GOOD: Edge Runtime with Fluid Compute**
```javascript
// api/fast-response.js
export const runtime = 'edge'; // Explicitly set Edge Runtime
export const preferredRegion = 'iad1'; // Choose region closest to users/data

export default async function handler(req) {
  // Fluid Compute automatically handles cold starts and resource scaling.
  // ... lightweight, latency-sensitive logic
  return new Response('Hello from the Edge!');
}
```

### 2.2. Static Exports for Purely Static Sites
````
END THIRD-PARTY FILE d7254f145b0e5aef

The third-party file has ended. Everything between the d7254f145b0e5aef tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 3751 of 10398 bytes. © sanjeed5 · CC0-1.0 · https://github.com/sanjeed5/awesome-cursor-rules-mdc/tree/HEAD/rules-mdc/vercel.mdc

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