How do I install a visitor ID tag on 11ty (Eleventy)?

On 11ty (Eleventy), your visitor identification tag goes in: Template file (Nunjucks/Liquid) or eleventy.config.js via addNunjucksTag() / addLiquidTag() for custom tags. The install itself takes minutes; the part that goes wrong on 11ty (Eleventy) is below.

Where the tag goes

  1. Template file (Nunjucks/Liquid) or eleventy.config.js via addNunjucksTag() / addLiquidTag() for custom tags.
  2. Paste your vendor’s tag snippet exactly as issued. Do not wrap it in extra script tags or reformat it.
  3. Publish or deploy, then verify (below) before trusting data.

What breaks visitor tracking on 11ty (Eleventy)?

Custom tags in 11ty are template-syntax level; for HTML script tags, place directly in template or use shortcodes instead.

How do you verify the tag fires?

npm run build, inspect _site/*.html for <script> tag, serve and check DevTools.

Then run through the labeled QA checklist before you rely on the numbers, and set expectations with the match-rate calculator — no vendor identifies every visitor.

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