Get a compliant banner live in about a minute. First, choose the tag setup that matches your site in [Choose your setup](/install/choose-setup/) or use the [Lightning configurator](https://demo.lightning-consent.io/). The final `lightning("init", …)` line depends on that choice. > **Warning — Using Google Tag Manager?** > Do not copy the generic init line below and then add a separate GTM snippet. > Use the [Google bridge](/integrations/bridges/#google-gtag--gtm) with your > `GTM-…` container ID. It owns the loader ordering; individual tags remain > managed in GTM. The setup is shown in the first tab below. ## Before you start You need three things — see [Prerequisites](/install/prerequisites/) for detail: - A **license key** (`k=8f3c…`). It's baked into the script URL and carries your `siteId`, so you usually don't set `siteId` in `init()`. - Your **domains registered** against the site. The SDK only runs on authorised hosts; everywhere else it's a harmless no-op (`localhost` is allowed for testing). - **Access to ``** — ideally as the *first* thing in it. ## Install The head block depends on who owns Google Consent Mode. When you use a Google bridge, the bridge supplies the default and the snippet stays smaller. Choose the setup before you paste it: #### Google Tag Manager Use this when your tags are managed in GTM. Replace `GTM-XXXXXXX` with your container ID, then configure each tag's Consent Settings in GTM. ```html ``` #### GA4 or Ads (no GTM) Use this when the CMP should load a Google tag directly. Replace the ID with your `G-…` or `AW-…` value. ```html ``` #### No Google tag Use the generic init when another system already owns your Google setup or your site has no Google tags. Add supported vendor bridges separately. ```html ``` 1. **Paste your selected snippet** at the very top of ``, before any site-hosted Google tag or other tracker. Replace `YOUR_LICENSE_KEY` and the example tag ID with your values. Bridge tabs omit the inline default because the bridge owns it. 2. **Load the page** and open its console. Run: ```js LightningCMP.debug(); ``` You'll see the resolved regulation, the Consent Mode signals, and a table of any scripts the CMP is gating. If that prints, you're installed. That's a complete, compliant install for the path you selected. The banner shows (or doesn't) according to the visitor's region, resolved at the edge. ## What each part does A one-line tour — the [line-by-line explainer](/install/snippet-explained/) goes deeper. | Part | Why it's there | | -------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | | `preconnect` | Warms the TLS connection to the edge so the first config round-trip is fast. Pure performance. | | `gtag('consent','default', …)` | The **Consent Mode default** for site-hosted Google tags. Bridge installs omit it because the Google bridge pushes the default before it loads its tag. | | The `lightning()` **queue stub** | Lets you load `cmp.js` `async` and still call `lightning('init', …)` immediately — calls are queued and replayed on load. | | `cmp.js?k=…` | The SDK (\~12 KB gzipped), `async`, never render-blocking. The `?k=` key authorises backend calls and carries your `siteId`. | | `lightning('init', { … })` | Boots the banner with your [config](/api/config-reference/). | > **Warning — Using Cloudflare Rocket Loader or a “defer all JS” optimiser?** > Rocket Loader (and WP Rocket, LiteSpeed, NitroPack…) rewrite and re-order your > scripts, which can make the Consent Mode default land *after* your Google tags — > GTM Preview then reports *“a tag read consent state before a default was set.”* > Add `data-cfasync="false"` to every Lightning `