Tagstack is now available as an MCP Server for Claude.ai, ChatGPT and more See the announcement · Get started

Audit any GTM container instantly

Paste a URL or container ID. Tagstack reads the public container, grades the setup, and shows every tag, trigger and variable.

No signup. No access to the container needed.

Try one: renault.fr lego.com GTM-KL36Q2B

Trusted by 2,000+ analytics experts at

The platform

Everything one scan unlocks

Audit

Assess container setup quality in seconds

Tagstack inspects the content of any Google Tag Manager container and grades the setup — consent mode, server-side, CMP, naming, performance.

Learn about Audit

Container Health

A 96%

Stack intelligence

Put a price on any martech stack

Every scan estimates what the detected stack costs per year. Spot redundant tools on your own site — or size a prospect's budget before the first call.

Learn about Martech cost

Estimated stack cost

$43,200 /year · 17 technologies

Segment CDP

$14,400/yr

Hotjar Analytics

$1,908/yr

Klaviyo Email

$8,400/yr

Optimizely A/B testing

$18,000/yr

+ 13 more detected on this container

Recovery

Recover any GTM container

Lost access to a Google Tag Manager container? Scan it, export it, and reimport it into GTM — tags, triggers and variables included.

Learn about Container export

Sharing

Share your audits with your team

Saved scans snapshot a container at audit time. Share results publicly with clients or teammates, and build a history to track how the setup evolves.

Learn about Saved scans

Agentic

Bring Tagstack data into your AI workflow

With the Tagstack MCP server, Claude, ChatGPT and other assistants can run scans and pull technology reports directly in conversation.

Learn about MCP

API

Automate audits and lead discovery

Run scans, save snapshots, or pull the full technology list for any domain straight from the API. Gather useful data for your lead qualification pipeline, all automated.

Learn about the API

terminal

$ curl "service.tagstack.io/api/scan?url=stripe.com" \
    -H "Authorization: Bearer YOUR_API_KEY"

{
  "success": true,
  "techList": ["GA4", "OneTrust", … ],
  "vitals": { "lcp": 1.2, "cls": 0.02 },
  "cloudflareDNS": false
}

The largest open index of GTM setups

Two years of scanning, auditing and recovering containers for thousands of analytics teams.

3M+

Containers scanned

400+

Containers recovered

50,000+

Technologies identified

Frequently asked questions

Read all FAQs

See what's inside your container

Paste a URL, get a graded audit in seconds. 50 free scans, no credit card.