CDN detector
How to tell if a website uses Fastly
By Marnix Geerkens. Published 2026-06-01. Updated 2026-06-01.
In short
To tell if a website uses Fastly, scan it with the free detector below. Look for an X-Served-By Fastly header or fastly in the via header. Fastly is a cdn tool: Fastly is a fast, developer friendly CDN with real time configuration. Many media and SaaS sites use it.
Detect Fastly on any website
brightsmile-dental.com
8 technologies across 7 categories · scanned May 20, 2026
Gaps and opportunities
Every gap is a service you could sell this business every month. Ranges below are typical agency pricing, not guarantees.
What is Fastly?
Fastly is a fast, developer friendly CDN with real time configuration. Many media and SaaS sites use it.
In the tech stack detector, Fastly shows up in the CDN group. Knowing a site runs Fastly tells you how it is built and what it is set up to do.
How to detect Fastly
Look for an X-Served-By Fastly header or fastly in the via header.
You do not have to dig through page source by hand. Paste the website into the detector above and it reports Fastly along with the CMS, analytics, pixels, hosting, payments, chat, email, and CRM the site uses.
Why it matters for agencies
Knowing a prospect runs Fastly (or does not) shapes your pitch. The detector also flags the gaps: if a site has no CRM, no chat widget, no review tool, or no ad pixel, that is a clear opening for a GoHighLevel CRM, an AI chat or voice agent, review automation, or a paid ads setup.
Frequently asked questions
How can I tell if a website uses Fastly?
Look for an X-Served-By Fastly header or fastly in the via header. The fastest way is to paste the site into the free detector at the top of this page; it reads the public technology profile and tells you whether Fastly is present, along with the rest of the stack.
What is Fastly?
Fastly is a fast, developer friendly CDN with real time configuration. Many media and SaaS sites use it.
Is the Fastly detector free?
Yes. You can scan any website for Fastly with no login and see the full technology stack right away. There is a fair daily limit per visitor, and unlimited scans come with the GoHighLevel 30-day free trial.
What category does Fastly belong to?
Fastly is grouped under CDN in the detector. You can browse every tool we track in that category on the CDN hub.
