# Code Injection > Add custom site-wide head and body code — verification tags, fonts, chat widgets, and third-party embeds. Source: https://knowledge.estage.com/project-settings/code-injection/ Part of the ESTAGE knowledge base (https://knowledge.estage.com). Full corpus: https://knowledge.estage.com/llms-full.txt --- The **Code Injection** tab lets you add custom code that runs across your entire site. Use it for anything that isn't a standard marketing pixel — those belong in [Marketing Tags](/project-settings/marketing-tags/). ## The two fields | Field | Where it loads | Common uses | | --- | --- | --- | | **Custom `` code** | In the document `` | Verification tags, web fonts, analytics loaders | | **Custom `` code** | At the start of the `` | Chat widgets, third-party embeds | Each field accepts up to **20,000 characters** and runs your code exactly as you paste it. ## Saving Click **Save custom code** to apply. The status line shows **All changes saved**, **Unsaved changes**, or an error. The button is disabled when nothing has changed. Changes appear in your live preview right away and on your published site after you publish. :::caution This code runs **as-is** on your live site. Only paste code from sources you trust — a bad snippet can break your pages or expose your visitors to risk. ::: ## Where each kind of code belongs - **This tab** — site-wide custom `` / `` code. - **[Marketing Tags](/project-settings/marketing-tags/)** — GTM, Meta Pixel, GA4, TikTok, LinkedIn by ID. - **Page settings → Scripts** — code you want on a **single page** only.