UTM Parameters and Redirects: What Should Be Preserved and What Should Not

Redirects can damage attribution

Teams often validate only the destination URL and forget that tracking parameters are part of the request experience. If redirects strip or duplicate UTM parameters, campaign reporting becomes unreliable.

What should usually happen

A redirect should preserve valid query parameters unless there is a deliberate normalization rule. The destination should not randomly lose utm_source or end up with duplicated parameters after multiple hops.

What to watch for

• —uppercase and lowercase parameter mismatches
• —double encoding after chained redirects
• —appending tracking values twice in edge rules or tag managers

Practical rule

Define one policy for parameter preservation before campaigns go live. Then test real campaign URLs, not only clean canonical URLs, because marketing traffic rarely arrives in the cleanest possible format.