Free API key setup in 2 minutes. No billing required for the free tier.

Steps

1. Open Google Cloud Console

Go to console.cloud.google.com

Sign in with any Google account. You don't need a paid Google Cloud account — the PSI API has a free tier.

2. Create or Select a Project

Click the project dropdown at the top of the page:

• New users: Click "New Project", give it a name like "PSI Testing", and create
• Existing users: Select an existing project or create a new one

3. Enable the PageSpeed Insights API

1. Go to APIs & Services → Library (or search "API Library" in the top search bar)
2. Search for "PageSpeed Insights API"
3. Click on it and press Enable

The API is now active for your project.

4. Create Credentials

1. Go to APIs & Services → Credentials
2. Click Create Credentials → API Key
3. Copy the key that appears

Your key is ready to use immediately.

Secure Your Key

API keys can be stolen and abused. A CS student received a $55,444 bill after their key was exposed on GitHub — attackers used it to call other billable GCP APIs. Always add restrictions.

For Server-Side Use

Restrict by IP address:

1. Click on your API key in the Credentials list
2. Under Application restrictions, select IP addresses
3. Add your server's IP address(es)
4. Save

Note: IP restrictions don't work with serverless platforms (Vercel, Cloudflare Workers, AWS Lambda) since they use dynamic IPs. Use HTTP referrer restrictions or a server-side proxy instead.

For Client-Side Use

Restrict by HTTP referrer:

1. Click on your API key in the Credentials list
2. Under Application restrictions, select HTTP referrers
3. Add your domain: yourdomain.com/*
4. Save

API Restrictions (Critical)

Always limit the key to only the PSI API — this prevents the billing nightmare above:

1. Under API restrictions, select Restrict key
2. Choose PageSpeed Insights API from the dropdown
3. Save

Test Your Key

Verify it works with a curl request:

curl "https://www.googleapis.com/pagespeedonline/v5/runPagespeed?url=https://example.com&key=YOUR_API_KEY"

A successful response returns JSON with Lighthouse data. An invalid key returns:

{
  "error": {
    "code": 400,
    "message": "API key not valid. Please pass a valid API key."
  }
}

Quotas

Monitor usage at APIs & Services → PageSpeed Insights API → Quotas.

The daily limit resets at midnight Pacific Time. Note: Google doesn't officially publish rate limits in their documentation. These values are from third-party testing and community reports. Your actual limits may vary.

Set up quota alerts: Go to IAM & Admin → Quotas & System Limits → find PageSpeed Insights API → Create usage alert at 50%, 80%, and 95% thresholds.

For higher limits: Create multiple GCP projects (each gets its own 25k/day quota) or request a quota increase in the Quotas section. Google is reportedly reasonable about increases for legitimate use cases.

Next Steps

• Node.js integration
• Python integration
• Handle rate limits

Skip the API Key Dance

Unlighthouse runs Lighthouse locally — no API keys, no quotas, no Google Cloud Console.

npx unlighthouse --site https://your-site.com

Related

• PageSpeed Insights API Guide
• Rate Limits
• PageSpeed Insights vs Unlighthouse