Every pixel and tag on a site is a channel through which data leaves. Over time they accumulate: forgotten tools, scripts from old campaigns, duplicate integrations. A quarterly inventory prevents data leaks, slowness and compliance problems.
The essentials in a definition
A pixel and tag audit is a periodic inventory of everything running on the site: what it is, who installed it, what data it collects and to whom it sends it. It avoids data leaks, forgotten tags and GDPR infringements. The tag manager helps centralise, and the CNPD gathers guidance on cookies and trackers.
How tags accumulate
Every campaign, tool and agency that passes through adds pixels and scripts. Rarely does anyone remove them. After two years the site loads dozens of scripts, some from companies that are no longer suppliers, others sending data with nobody knowing why.
This increases the risk of data leaks, slows pages down and complicates consent.
A quarterly inventory
List all tags, pixels and scripts: which platform, what purpose, what data they collect, where they fire, who is responsible and since when they have existed. Use the tag manager, browser developer tools and detection extensions.
Compare with the record of processing and the cookie notice. Any item not listed must be explained or removed.
A quarterly tag inventory
- List all tags and pixels
- Check purpose, legal basis and owner
- Remove what is unused
- Confirm firing only after consent
Deciding what stays
For each item ask: does it serve a current purpose? Is there a legal basis and consent? Is there a simpler alternative? If the answer is no or I do not know, pause it and remove it after a quick check.
Also verify that tags fire only after consent, where applicable.
What nobody knows is on the site is what carries the most risk.
Keeping control
Centralise tag management in one place. Define who may add and approve. Require documentation from agencies and suppliers. Do a quick review whenever you launch a campaign or change tools.
Measuring page speed before and after the clean-up usually shows a visible benefit.
Decision table
| Inventory field | Question | Action |
|---|---|---|
| Name and vendor | What is it and who supplies it? | Document contract and purpose |
| Data collected | What data and where do they go? | Check minimisation and transfers |
| Firing condition | When does it fire and does it respect consent? | Test with and without consent |
| Owner and use | Who uses it and is it still needed? | Remove if unused |
Common mistakes to avoid
- Inventory only in memory. If it is not written down, it is not maintained.
- Ignoring third-party tags. A third-party script can load others without control.
- Not repeating. New tags appear; audit quarterly.
How to measure the result
Count the number of active tags, those removed by audit and those without owner or purpose; the aim is for the last two to be zero.
Limits and exceptions
A one-off audit does not prevent new problems: marketing teams, plugins and suppliers add tags continuously. Without an approval process for new tools, the inventory gets outdated quickly. Combine the audit with rules (who can install, who approves) and with automatic monitoring where possible. On large sites, consider dedicated tools.
Illustrative example
Illustrative example: a shop analyses the site’s network traffic and finds seven scripts nobody knew were active, two from discontinued tools, sending data to third parties. It removes them, updates the privacy policy and creates an inventory with an owner. The site becomes faster and legal exposure falls.
In practice: checkpoints
Schedule the inventory every quarter and assign an owner. List each tag, vendor, purpose, data sent and legal basis, mark what is no longer used and remove it. Check that new tags went through approval and that consent is respected by every tag. Keep the list in a shared document with the date of the last review, so an auditor or a new colleague can understand the setup in minutes instead of days.
Frequently asked questions
How often should I take inventory?
Quarterly and whenever you change agency or tools.
How do I find forgotten tags?
With the tag manager, browser tools and detection extensions.
Does removing tags improve the site?
Often yes: fewer scripts, faster pages and less risk.
How do I find out what runs on my site?
With browser developer tools, the tag manager and cookie and script audit tools.
How often should I audit?
Quarterly and whenever a new tool or plugin is installed.
A quarterly inventory of pixels, tags and scripts, with purpose, data and owner, avoids data leaks and infringements and speeds up the site.
Sources and recommended reading
- Tag Manager Help: introduction
- General Data Protection Regulation (GDPR)
- Portuguese Data Protection Authority (CNPD)
Last editorial review: October 2026. Informational content; always confirm current conditions in the official sources before deciding.