Vercel Migration Deep Dive

What it does

When your agent uses it

• Migrating from Netlify
• Cloudflare to Vercel
• Re-platforming an existing Vercel application
• With phrases like migrate to vercel

Example prompts

• “migrate to vercel”
• “vercel migration”
• “switch to vercel”
• “/vercel-migration-deep-dive”

Requirements

• Node.js
• Compatibility (from SKILL.md): Designed for Claude Code
• Pre-approved tools (allowed-tools): Read, Write, Edit, Bash(vercel:*), Bash(npm:*), Bash(npx:*)

Workflow steps

6 steps, taken from the step headings in SKILL.md.

1. 1Configuration Mapping
2. 2Migrate Functions
3. 3Migrate Environment Variables
4. 4Incremental Migration (Strangler Fig)
5. 5DNS Cutover
6. 6Validate Feature Parity

What it can do on your machine

Read from SKILL.md and the folder at commit cfae287. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Write
  • Edit
  • Bash(vercel:*)
  • Bash(npm:*)
  • Bash(npx:*)

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • vercel
  • curl
  • jq
  • npm
  • netlify

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • vercel.com
  • martinfowler.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Designed for Claude Code

  From compatibility in the SKILL.md frontmatter.

Context cost

Vercel Migration Deep Dive loads about 2k tokens when it runs, and up to ~2.9k if it reads all its reference files. Until then it costs about 94 tokens; SKILL.md has 483 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~94

When it runs · the whole SKILL.md, loaded when a task matches

~2k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~2.9k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NoteMentions a .env fileSKILL.md:142

  '.[] | "\(.key)=\(.values[0].value)"' > .env.migration

• NoteMentions a .env fileSKILL.md:147

  done < .env.migration

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from jeremylongshore/tons-of-skills-marketplace at commit cfae287, republished under its MIT licence (© jeremylongshore). 483 words, ~1,984 tokens.

name

vercel-migration-deep-dive

description

Migrate to Vercel from other platforms or re-architecture existing Vercel deployments. Use when migrating from Netlify, AWS, or Cloudflare to Vercel, or when re-platforming an existing Vercel application. Trigger with phrases like "migrate to vercel", "vercel migration", "switch to vercel", "netlify to vercel", "aws to vercel", "vercel replatform".

allowed-tools

Read, Write, Edit, Bash(vercel:*), Bash(npm:*), Bash(npx:*)

compatibility

Designed for Claude Code

version

1.18.0

license

MIT

author

Jeremy Longshore <jeremy@intentsolutions.io>

tags

saas, vercel, migration, replatform

// Netlify _redirects → vercel.json
// FROM: /old-page /new-page 301
// TO:
{
  "redirects": [
    { "source": "/old-page", "destination": "/new-page", "permanent": true }
  ]
}

// Netlify _headers → vercel.json
// FROM: /* X-Frame-Options: DENY
// TO:
{
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        { "key": "X-Frame-Options", "value": "DENY" }
      ]
    }
  ]
}

// AWS Lambda handler → Vercel Function
// FROM:
export const handler = async (event) => {
  return { statusCode: 200, body: JSON.stringify({ hello: 'world' }) };
};

// TO:
import type { VercelRequest, VercelResponse } from '@vercel/node';
export default function handler(req: VercelRequest, res: VercelResponse) {
  res.status(200).json({ hello: 'world' });
}

# Create Vercel project
vercel link

# Move function files to api/ directory
mkdir -p api
# Convert each function to Vercel format

# Install Vercel types
npm install --save-dev @vercel/node

# Export from current platform, add to Vercel
# Netlify:
netlify env:list --json | jq -r '.[] | "\(.key)=\(.values[0].value)"' > .env.migration

# Add each to Vercel with proper scoping
while IFS='=' read -r key value; do
  echo "$value" | vercel env add "$key" production preview development
done < .env.migration

# Verify
vercel env ls

// Phase 1: Route /api/* to Vercel, keep everything else on old platform
// On old platform, add a rewrite/proxy:
// /api/* → https://my-app.vercel.app/api/*

// Phase 2: Move static pages to Vercel
// Update DNS for staging subdomain first:
// staging.example.com → cname.vercel-dns.com

// Phase 3: Move production
// Update DNS A record: example.com → 76.76.21.21

# Add domain to Vercel
vercel domains add example.com

# Verify domain ownership
vercel domains inspect example.com

# DNS records to set:
# Apex domain (example.com):
#   A → 76.76.21.21
#
# Subdomain (www.example.com):
#   CNAME → cname.vercel-dns.com
#
# Or transfer nameservers to Vercel:
#   NS → ns1.vercel-dns.com
#   NS → ns2.vercel-dns.com

# Wait for DNS propagation (check with dig)
dig example.com A +short
# Should return 76.76.21.21

# SSL certificate auto-provisions after DNS verification

# Compare old and new deployments
# Test all routes
for path in "/" "/about" "/api/health" "/api/users"; do
  echo "=== $path ==="
  echo "Old:"
  curl -sI "https://old.example.com${path}" | head -3
  echo "New:"
  curl -sI "https://my-app.vercel.app${path}" | head -3
done

# Compare headers
diff <(curl -sI https://old.example.com/ | sort) \
     <(curl -sI https://my-app.vercel.app/ | sort)

# Check redirects still work
curl -sI https://my-app.vercel.app/old-page | grep Location

© jeremylongshore, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files (references) in skills/.curated/vercel-migration-deep-dive of jeremylongshore/tons-of-skills-marketplace.

• SKILL.md
• references/errors.md
• references/examples.md
• references/implementation-plan.md
• references/pre-migration-assessment.md

Open the folder on GitHubat commit cfae287