# Checking a tag installation without paid tools

> Auditing a tracking install end to end doesn’t require a paid monitoring subscription. Four free tools cover the vast majority of cases: Google Tag Manager’s preview mode, the Tag Assistant extension, the Meta Pixel Helper extension, and the browser developer tools’ Network tab.

- Source canonique : [https://allaux.fr/en/services/tracking/verifier-installation-balise-sans-outil-payant](https://allaux.fr/en/services/tracking/verifier-installation-balise-sans-outil-payant)
- Langue : EN
- Dernière mise à jour : 2026-09-30

## Direct answer

> Open developer tools (F12), Network tab, reload the page and filter on gtm.js: a 200 response carrying the expected container ID proves it loads. Then switch to Google Tag Manager Preview mode to see which tags fire page by page, and to Meta Pixel Helper for the pixel. None of these three tools costs anything.

## The situations I handle

- Need to check a tracking install after going live, with no budget for a tool
- Doubt over whether tags still fire correctly after a theme or module change
- No way to tell if GTM, GA4 or the Meta pixel are actually active
- A provider claims tracking is in place but nothing is easily verifiable
- Wanting to audit an install yourself before paying for an external audit
- A check to repeat regularly after every major site update

## A full audit with only free tools

1. **1. Confirm the GTM container is present (Network tab)** — Dev tools (F12), Network tab, reload the page, filter on gtm.js. A 200 request with the expected ID (GTM-XXXXXXX): the container loads. Nothing: the tag isn’t installed on that page, before configuration even comes into it.
2. **2. Launch Google Tag Manager’s preview mode** — From GTM, click Preview, enter the site’s URL: a debug session opens in a new tab with a ’Tag Assistant Connected’ banner. I browse normally: every page lists its fired tags (Tags Fired) and unfired ones (Tags Not Fired).
3. **3. Check every checkout event one by one** — I walk a full journey: product page, cart, checkout start, payment, confirmation. At each step I click the event (view_item, add_to_cart, begin_checkout, purchase) and open Variables to check value, currency, items, transaction_id.
4. **4. Install and use Tag Assistant outside GTM** — For a gtag.js tag placed directly without GTM, or a quick check, the Tag Assistant extension lists Google tags detected on the page and flags common configuration errors.
5. **5. Install and use Meta Pixel Helper** — The extension shows an icon with a badge as soon as a Meta pixel is detected. I click it to see events sent (PageView, ViewContent, AddToCart, Purchase) and warnings, such as a missing value parameter.
6. **6. Confirm every real send in the Network tab** — On top of the extensions, I filter Network on collect (Google) and tr (Meta) during each action. Seeing the request leave at the right moment, to the right domain, is the most direct proof an event was sent.
7. **7. Repeat the test in private browsing, consent declined** — Private window, decline consent on the banner, replay the journey. Analytics and advertising tags should stay silent in preview mode or Network: otherwise, it’s a consent configuration issue, distinct from a tracking problem.

## What these tools don’t replace

These four tools cover most of a one-off audit, with limits worth knowing:

They check the moment of the test, not continuously: a paid monitoring tool alerts automatically if a tag breaks later.

They show what fires on the browser side, not a server-side send like Meta’s Conversions API, which leaves the server directly.

A tag that fires correctly in testing can still fail for a real visitor due to an ad blocker: the audit confirms the install, not that 100% of visitors will be measured.

## A regular audit after every major update

> Repeating this after a theme, payment module or platform update helps catch a broken tag before it skews weeks of statistics.

## Go further

- **Installing Google Tag Manager on PrestaShop** — Setting up the container and dataLayer correctly from the start. ([/services/tracking/google-tag-manager-prestashop](/services/tracking/google-tag-manager-prestashop))
- **Ecommerce events that matter** — The list of recommended GA4 events and their parameters. ([/services/tracking/evenements-ecommerce-qui-comptent](/services/tracking/evenements-ecommerce-qui-comptent))
- **My conversions aren’t showing up** — The ordered method when a specific event is missing. ([/services/tracking/conversions-ne-remontent-pas](/services/tracking/conversions-ne-remontent-pas))
- **Duplicates in the statistics** — Using the same tools to spot a tag installed twice. ([/services/tracking/doublons-statistiques-causes](/services/tracking/doublons-statistiques-causes))

## FAQ

### Do I need a Google Ads or GA4 account to use GTM preview mode?

No, read access to the site’s GTM container is enough to launch a preview session.

### Do Tag Assistant and GTM preview mode do the same thing?

They overlap partly: preview mode shows variables and dataLayer detail, Tag Assistant is limited to detecting Google tags present, with or without GTM.

### Are these free tools enough for Meta’s server-side Conversions API?

No, the server-side send doesn’t go through the browser: check Meta’s Events Manager directly, which shows the source of every event received.

### Can this audit run directly on the live site?

Yes, these tools don’t interfere with other visitors: they read what happens in your own browser during the test.

### How long does a full audit take with this method?

Between twenty and forty minutes for a standard checkout, once extensions are installed and a test journey is planned.