UTM Link Builder

About UTM Link Builder

Enter a landing URL plus utm_source / utm_medium / utm_campaign (optional utm_term and utm_content) and get a clean GA4 tracking link ready to copy. The tool auto-applies the three most error-prone hygiene rules: values lowercased with whitespace collapsed to underscores (GA4 is case-sensitive — Spring and spring become two campaigns), and existing utm params on the pasted URL replaced instead of stacked. Common medium presets included. Runs entirely in your browser.

FAQ

How do utm_source and utm_medium actually differ?

One-line mnemonic: source answers WHO, medium answers WHAT KIND. utm_source is the referrer's name (google, xiaohongshu, newsletter, weibo); utm_medium is the marketing channel type (cpc, email, social, referral). The same platform can appear under different mediums: an organic Xiaohongshu post is source=xiaohongshu&medium=organic_social, a promoted note is medium=paid_social. Keep the medium vocabulary small and stable or your GA4 channel reports become unreadable.

Why force lowercase-with-underscores? I wanted camelCase.

Because GA4 dimension values are case-sensitive: utm_campaign=SpringSale and springsale are recorded as two campaigns and your reports split instantly. Underscores are also the common convention — plus signs and raw spaces get mangled by some email systems, while hyphens and underscores are always URL-safe. This tool lowercases and collapses whitespace but never rewrites your existing hyphens/underscores; if your team already standardized on hyphens, keep typing them.

What if the URL I paste already has utm params?

This tool REPLACES them, never stacks — avoiding ambiguous links like utm_source=old&utm_source=new (browser behaviour varies and the report is guaranteed dirty). Any non-utm query params on the landing page (?promo=early and friends) survive untouched, and so does the hash (#section). Paste an old link in, rename the campaign, copy the rebuilt link out.