Reference

Every install snippet you'd copy-paste, in one place.

These are the only HTML snippets that touch a site directly. Everything else — conversions, custom events, audiences — lives inside GTM or the ad platform. Where a GTM template exists, use that instead; full walkthroughs in the How-To guides and Template Gallery.

Google Tag Manager

Container snippet — <head>

Where to find the real version

tagmanager.google.com → Admin → Install Google Tag Manager

How to install

Paste as high as possible inside the <head> of every page on your site.

Common mistakes

Only one GTM container per site — multiple containers double-fire every tag.
Don't wrap it in <script type="module">. It must be a normal script.
If you load it via a CMS, make sure it runs before any cookie banner that blocks scripts.
Place AFTER your Consent Mode v2 default block (see the Consent How-To).

<!-- Google Tag Manager — replace GTM-XXXXXXX with your container ID -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXXX');</script>
<!-- End Google Tag Manager -->

Highlighted values are placeholders — swap them for your own IDs before going live.

Google Tag Manager

Container snippet — <body> noscript

Where to find the real version

Same screen as the <head> snippet — copy the second block.

How to install

Paste immediately after the opening <body> tag. Lets GTM work when JavaScript is disabled.

Common mistakes

Often forgotten — without it, ~1% of users won't be measured.
Make sure the GTM-XXXXXXX ID matches the <head> snippet exactly.

<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-XXXXXXX"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->

Highlighted values are placeholders — swap them for your own IDs before going live.

Google

Consent Mode v2 — default block

Where to find the real version

Required if you advertise to EEA/UK users

How to install

Paste in <head> BEFORE the GTM container snippet. Sets denied defaults for EEA/UK regions.

Common mistakes

Placed AFTER GTM — defaults arrive too late, first tags fire ungated.
Missing ad_user_data / ad_personalization (the 'v2' signals).
Region list incomplete — keep it in sync with the EEA + UK + Switzerland.

<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('consent', 'default', {
    'ad_storage': 'denied',
    'ad_user_data': 'denied',
    'ad_personalization': 'denied',
    'analytics_storage': 'denied',
    'functionality_storage': 'granted',
    'security_storage': 'granted',
    'wait_for_update': 500,
    'region': ['GB','CH','DK','DE','FR','IE','IT','ES','SE','NO','FI',
               'NL','BE','AT','PL','PT','CZ','HU','RO','GR','BG','HR',
               'CY','EE','LV','LT','LU','MT','SI','SK','IS','LI']
  });
</script>

Highlighted values are placeholders — swap them for your own IDs before going live.

Universal

Initialise dataLayer (always do this first)

Where to find the real version

Standard pattern — no source needed.

How to install

Paste in <head> BEFORE the GTM container snippet. Guarantees dataLayer exists.

Common mistakes

If you push BEFORE GTM loads without this, the array doesn't exist and the push silently no-ops.

<script>window.dataLayer = window.dataLayer || [];</script>

Highlighted values are placeholders — swap them for your own IDs before going live.

GA4

Google tag (gtag.js) — direct install (NO-GTM fallback)

Where to find the real version

analytics.google.com → Admin → Data Streams → your Web stream → Install manually

How to install

Paste inside <head>. ONLY if you're not installing GA4 via GTM. If you have GTM, add GA4 through a Google Tag in the container instead.

Common mistakes

Don't run gtag.js AND a GA4 tag inside GTM at the same time — duplicate pageviews.
Replace G-XXXXXXXXXX with your own Measurement ID (Web stream).
Conversion / event tags belong inside GTM or GA4 — don't hard-code them on the site.

<!-- Google tag (gtag.js) — replace G-XXXXXXXXXX with your Measurement ID -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-XXXXXXXXXX"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());
  gtag('config', 'G-XXXXXXXXXX');
</script>

Highlighted values are placeholders — swap them for your own IDs before going live.

TikTok

TikTok Pixel — direct install

Where to find the real version

ads.tiktok.com → Tools → Events → Web Events → your pixel → Install Pixel Code

How to install

Paste inside <head>. Replace C-XXXXXXXXX with your Pixel Code.

Common mistakes

Default currency = USD. Always pass currency explicitly on track calls.
Capture ttclid from the URL on landing into a 1P cookie or your dataLayer.
Pair with Events API (server-side) via sGTM for proper match strength.

<!-- TikTok Pixel — replace C-XXXXXXXXX -->
<script>
!function (w, d, t) {
  w.TiktokAnalyticsObject=t;var ttq=w[t]=w[t]||[];ttq.methods=["page","track",
  "identify","instances","debug","on","off","once","ready","alias","group",
  "enableCookie","disableCookie"];ttq.setAndDefer=function(t,e){t[e]=function(){
  t.push([e].concat(Array.prototype.slice.call(arguments,0)))}};
  for(var i=0;i<ttq.methods.length;i++)ttq.setAndDefer(ttq,ttq.methods[i]);
  ttq.instance=function(t){for(var e=ttq._i[t]||[],n=0;n<ttq.methods.length;n++)
  ttq.setAndDefer(e,ttq.methods[n]);return e};ttq.load=function(e,n){
  var i="https://analytics.tiktok.com/i18n/pixel/events.js";ttq._i=ttq._i||{};
  ttq._i[e]=[];ttq._i[e]._u=i;ttq._t=ttq._t||{};ttq._t[e]=+new Date;
  ttq._o=ttq._o||{};ttq._o[e]=n||{};n=document.createElement("script");
  n.type="text/javascript";n.async=!0;n.src=i+"?sdkid="+e+"&lib="+t;
  e=document.getElementsByTagName("script")[0];e.parentNode.insertBefore(n,e)};
  ttq.load('C-XXXXXXXXX');
  ttq.page();
}(window, document, 'ttq');
</script>

Highlighted values are placeholders — swap them for your own IDs before going live.

Reddit Pixel — direct install

Where to find the real version

ads.reddit.com → Events Manager → Conversions → Install Pixel

How to install

Paste inside <head>. Replace YOUR_REDDIT_PIXEL_ID.

Common mistakes

7-day click attribution by default — shorter than Meta. Don't compare like-for-like.
Pair with Reddit CAPI if budgets are significant.

<!-- Reddit Pixel -->
<script>
!function(w,d){if(!w.rdt){var p=w.rdt=function(){p.sendEvent?p.sendEvent.apply(p,arguments):p.callQueue.push(arguments)};
p.callQueue=[];var t=d.createElement("script");t.src="https://www.redditstatic.com/ads/pixel.js",t.async=!0;
var s=d.getElementsByTagName("script")[0];s.parentNode.insertBefore(t,s)}}(window,document);
rdt('init','YOUR_REDDIT_PIXEL_ID', { optOut: false, useDecimalCurrencyValues: true });
rdt('track', 'PageVisit');
</script>

Highlighted values are placeholders — swap them for your own IDs before going live.

LinkedIn Insight Tag — direct install

Where to find the real version

Campaign Manager → Analyze → Insight Tag

How to install

Paste inside <body>. Replace YOUR_PARTNER_ID.

Common mistakes

Don't fire on staging — it pollutes audiences fast.
B2B: add LinkedIn CAPI for longer attribution windows.

<!-- LinkedIn Insight Tag -->
<script type="text/javascript">
_linkedin_partner_id = "YOUR_PARTNER_ID";
window._linkedin_data_partner_ids = window._linkedin_data_partner_ids || [];
window._linkedin_data_partner_ids.push(_linkedin_partner_id);
(function(l) { if (!l){window.lintrk = function(a,b){window.lintrk.q.push([a,b])};
window.lintrk.q=[]}var s=document.getElementsByTagName("script")[0];
var b=document.createElement("script");b.type="text/javascript";b.async=true;
b.src="https://snap.licdn.com/li.lms-analytics/insight.min.js";
s.parentNode.insertBefore(b,s);})(window.lintrk);
</script>
<noscript><img height="1" width="1" style="display:none;" alt=""
src="https://px.ads.linkedin.com/collect/?pid=YOUR_PARTNER_ID&fmt=gif" /></noscript>

Highlighted values are placeholders — swap them for your own IDs before going live.

Microsoft

Microsoft UET Tag — direct install

Where to find the real version

Microsoft Ads → Tools → UET tag

How to install

Paste inside <head>. Replace YOUR_UET_TAG_ID.

Common mistakes

Often forgotten as part of Google Ads import — UET is separate.
Enable Enhanced Conversions for Microsoft Ads (similar to Google's).

<!-- Microsoft UET Tag -->
<script>
(function(w,d,t,r,u){var f,n,i;w[u]=w[u]||[],f=function(){var o={ti:"YOUR_UET_TAG_ID",enableAutoSpaTracking:true};o.q=w[u],w[u]=new UET(o),w[u].push("pageLoad")},
n=d.createElement(t),n.src=r,n.async=1,n.onload=n.onreadystatechange=function(){var s=this.readyState;s&&s!=="loaded"&&s!=="complete"||(f(),n.onload=n.onreadystatechange=null)},
i=d.getElementsByTagName(t)[0],i.parentNode.insertBefore(n,i)})(window,document,"script","//bat.bing.com/bat.js","uetq");
</script>

Highlighted values are placeholders — swap them for your own IDs before going live.

Pinterest Tag — direct install

Where to find the real version

ads.pinterest.com → Conversions → Pinterest Tag

How to install

Paste inside <head>. Replace YOUR_TAG_ID.

Common mistakes

Event names omit underscores: 'addtocart' not 'add_to_cart'.
Pair with Pinterest Conversions API for proper coverage.

<!-- Pinterest Tag -->
<script>
!function(e){if(!window.pintrk){window.pintrk = function () {
window.pintrk.queue.push(Array.prototype.slice.call(arguments))};var
n=window.pintrk;n.queue=[],n.version="3.0";var
t=document.createElement("script");t.async=!0,t.src=e;var r=document.getElementsByTagName("script")[0];
r.parentNode.insertBefore(t,r)}}("https://s.pinimg.com/ct/core.js");
pintrk('load', 'YOUR_TAG_ID');
pintrk('page');
</script>
<noscript><img height="1" width="1" style="display:none;" alt=""
src="https://ct.pinterest.com/v3/?event=init&tid=YOUR_TAG_ID&noscript=1" /></noscript>

Highlighted values are placeholders — swap them for your own IDs before going live.

Snap

Snap Pixel — direct install

Where to find the real version

ads.snapchat.com → Events Manager

How to install

Paste inside <head>. Replace YOUR_PIXEL_ID.

Common mistakes

Always pass hashed email + phone — match rate is volatile without it.

<!-- Snap Pixel -->
<script type='text/javascript'>
(function(e,t,n){if(e.snaptr)return;var a=e.snaptr=function(){
a.handleRequest?a.handleRequest.apply(a,arguments):a.queue.push(arguments)};
a.queue=[];var s='script';r=t.createElement(s);r.async=!0;
r.src=n;var u=t.getElementsByTagName(s)[0];
u.parentNode.insertBefore(r,u);})(window,document,
'https://sc-static.net/scevent.min.js');
snaptr('init', 'YOUR_PIXEL_ID', { user_email: '__INSERT_USER_EMAIL__' });
snaptr('track', 'PAGE_VIEW');
</script>

Highlighted values are placeholders — swap them for your own IDs before going live.

X (Twitter)

X Universal Website Tag

Where to find the real version

ads.x.com → Tools → Conversion Tracking

How to install

Paste inside <head>. Replace YOUR_PIXEL_ID.

Common mistakes

X has rebranded the tag multiple times — check for the latest version.

<!-- X (Twitter) Universal Website Tag -->
<script>
!function(e,t,n,s,u,a){e.twq||(s=e.twq=function(){s.exe?s.exe.apply(s,arguments):s.queue.push(arguments);
},s.version='1.1',s.queue=[],u=t.createElement(n),u.async=!0,u.src='https://static.ads-twitter.com/uwt.js',
a=t.getElementsByTagName(n)[0],a.parentNode.insertBefore(u,a))}(window,document,'script');
twq('config','YOUR_PIXEL_ID');
</script>

Highlighted values are placeholders — swap them for your own IDs before going live.

Shopify

Customer Events — GA4 purchase (Shopify-native)

Where to find the real version

Shopify Admin → Settings → Customer events → Add custom pixel

How to install

Paste into a Custom Pixel in Shopify (NOT into theme.liquid). Shopify runs custom pixels in a sandboxed iframe — you cannot use window, document, dataLayer, gtag() or fbq() directly. Use the analytics.subscribe API plus fetch / Measurement Protocol / CAPI.

Common mistakes

Custom Pixels are sandboxed — no access to window/document/dataLayer. Send data via Measurement Protocol or CAPI using fetch.
checkout_completed is the only reliable purchase event on Shopify — Shopify hides the thank-you page from your theme, so theme-level GA4 / Pixel purchase tags will NOT fire.
Use checkout.order.id (or checkout.token) as transaction_id / event_id so server-side dedupe works.
Shopify's Google / Meta channel apps ALSO fire purchase events — disable one side or you'll double-count.
Test with a real (or Bogus Gateway) order in incognito — Shopify's preview tool doesn't fire checkout_completed.

// Shopify Customer Events — Custom Pixel
// GA4 purchase via Measurement Protocol (sandbox-safe)
// Replace G-XXXXXXXXXX and YOUR_API_SECRET (GA4 → Admin → Data Streams → Measurement Protocol API secrets)

analytics.subscribe('checkout_completed', (event) => {
  const checkout = event.data.checkout;
  const clientId = event.clientId || (Date.now() + '.' + Math.random().toString(36).slice(2));

  const payload = {
    client_id: clientId,
    events: [{
      name: 'purchase',
      params: {
        transaction_id: checkout.order?.id ?? checkout.token,
        value: checkout.totalPrice.amount,
        currency: checkout.currencyCode,
        tax: checkout.totalTax?.amount ?? 0,
        shipping: checkout.shippingLine?.price?.amount ?? 0,
        items: checkout.lineItems.map((li, i) => ({
          item_id: li.variant?.sku ?? li.variant?.id ?? li.id,
          item_name: li.title,
          item_variant: li.variant?.title,
          price: li.variant?.price?.amount,
          quantity: li.quantity,
          index: i,
        })),
      },
    }],
  };

  fetch('https://www.google-analytics.com/mp/collect?measurement_id=G-XXXXXXXXXX&api_secret=YOUR_API_SECRET', {
    method: 'POST',
    body: JSON.stringify(payload),
    keepalive: true,
  });
});

Highlighted values are placeholders — swap them for your own IDs before going live.

Shopify

Customer Events — Meta CAPI purchase (Shopify-native)

Where to find the real version

How to install

Paste into a Custom Pixel. For production, proxy this through your own server route so the access token isn't exposed in the browser — the snippet below is for testing or for stores where the pixel is locked down to your own staff.

Common mistakes

Never ship the CAPI access token in the browser long-term — proxy via a server route (e.g. /api/public/meta-capi).
event_id must match the Pixel-side purchase event_id for Meta to dedupe.
Hash email & phone with SHA-256 before sending (the snippet does it).
Use action_source: 'website' — 'system_generated' gets filtered.

// Shopify Customer Events — Meta CAPI (testing — proxy in production)
// Replace YOUR_PIXEL_ID and YOUR_CAPI_TOKEN

async function sha256(str) {
  const buf = new TextEncoder().encode(str.trim().toLowerCase());
  const hash = await crypto.subtle.digest('SHA-256', buf);
  return Array.from(new Uint8Array(hash)).map(b => b.toString(16).padStart(2,'0')).join('');
}

analytics.subscribe('checkout_completed', async (event) => {
  const c = event.data.checkout;
  const eventId = c.order?.id ?? c.token;

  const userData = {};
  if (c.email) userData.em = [await sha256(c.email)];
  if (c.phone) userData.ph = [await sha256(c.phone.replace(/\D/g,''))];

  await fetch('https://graph.facebook.com/v19.0/YOUR_PIXEL_ID/events?access_token=YOUR_CAPI_TOKEN', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    keepalive: true,
    body: JSON.stringify({
      data: [{
        event_name: 'Purchase',
        event_time: Math.floor(Date.now()/1000),
        event_id: eventId,
        action_source: 'website',
        event_source_url: event.context.window.location.href,
        user_data: userData,
        custom_data: {
          currency: c.currencyCode,
          value: Number(c.totalPrice.amount),
          contents: c.lineItems.map(li => ({
            id: li.variant?.sku ?? li.variant?.id,
            quantity: li.quantity,
            item_price: Number(li.variant?.price?.amount ?? 0),
          })),
          content_type: 'product',
        },
      }],
    }),
  });
});

Highlighted values are placeholders — swap them for your own IDs before going live.

A note on direct-install vs GTM templates

Every snippet here can also be installed via a GTM template (see the Template Gallery). Direct install is for cases where you don't have GTM, you're testing, or you're handing off to a developer. Production setups should use templates so you can version, preview and roll back tracking changes without touching code.