Varify URL query parameters are removed from the URL
Table of contents
How to recognize the error
When loading the editor or viewing the preview variations via the corresponding preview links, important URL query parameters are appended to the URL.
If these are removed or blocked by your website, the editor or other functions, such as the preview links, may no longer work properly.
How to fix the error
Many caching systems, CDNs (e.g., Cloudflare), tag managers, or consent tools normalize URLs and remove unknown query parameters in the process—this can break Varify functionality if the parameters are lost during a redirect, reload, or cache lookup. Therefore, the following parameters must be explicitly set as Whitelist (or as „preserve query params“) should be specified in your cache/redirect configuration.
The Varify Parameters in Detail
| parameters. | Purpose |
|---|---|
varify-editor | Enables the Visual Editor on the page—is set when an experiment is being edited in the editor. Without this parameter, the page does not load in editor mode. |
varify-preview | Generates a preview of a specific variation before the experiment goes live. Used for QA and approval workflows, among other things. |
varify-force | Forces a specific variation assignment, regardless of the regular traffic distribution (e.g., for debugging or targeted testing of a variation). |
varify-variation-id | Returns the ID of a specific variation—typically along with varify-force or varify-preview used to enforce or display this specific variation. |
varify-variation-name | Similar to varify-variation-id, but it refers to the variation by its name rather than its ID—for more readable preview and debug links. |
va-red | Used for redirects in the context of split URL tests to ensure that visitors remain correctly assigned to the target variation, even after a redirect. |
Recommendation for Whitelisting
- Add all six parameters (exactly as shown, in lowercase and with hyphens) to your URL parameter whitelist—whether in the CDN cache key, the consent/tracking cleaner, or in redirect rules.
- Make sure they are preserved in both internal redirects and cache bypasses, since
varify-previewandvarify-forceotherwise they will lose their function. - If you're using Cloudflare Page Rules or Cache Rules: These parameters must be included in the „Cache Key“ or explicitly excluded so that different variations do not share the same cache entry.