UTM parameters
URL query parameters that track which email/campaign drove traffic — utm_source, utm_medium, utm_campaign, etc.
UTM parameters are URL query parameters appended to links in your emails (and other marketing channels) that let analytics tools (Google Analytics, PostHog, etc.) attribute downstream traffic and conversions to the specific email or campaign that drove them. The standard parameters are utm_source, utm_medium, utm_campaign, utm_term, and utm_content.
A typical email link looks like: https://yourbrand.com/product?utm_source=newsletter&utm_medium=email&utm_campaign=q4-launch. The analytics tool reads these parameters and tags the resulting session as coming from that specific source/campaign/etc.
UTM hygiene matters more than most teams realize. Inconsistent naming (utm_medium=email vs utm_medium=Email vs utm_medium=mail) fractures reporting. A team-wide UTM convention, documented and enforced via shared templates, prevents months of attribution headaches later. Most ESPs offer UTM-builder integrations that enforce conventions automatically.