Running Tailor Alongside Another Experimentation Platform

Tailor targets specific traffic using parameters such as utm_campaign, utm_term, or utm_medium, while your other platform runs on the traffic without those parameters.

Best when: Tailor is scoped to the traffic you're buying and the other platform is testing the broader site experience. Nothing changes on the other platform's side. See the Targeting Guide for the full parameter list.

Add a parameter such as tailor=1 to the URLs Tailor should own, then gate the other platform's experiments on its absence. Tailor-eligible traffic carries the flag, the other platform sits out, and everything else runs as usual.

// Audience or activation condition in the other platform:
// run only when Tailor does not own this visit.
!new URLSearchParams(window.location.search).has("tailor")

Best when: The other platform owns most of the traffic and you want a carve-out for Tailor without rewriting its audience rules. It needs a one-time change on the other platform's side, and whoever administers it has to agree to the convention.

Each platform owns different URL paths. Tailor runs experiments on the paid landing pages, the other platform runs on the core site, and neither touches the other's pages.

Best when: Ownership is already split by team. Product and Engineering test the app and core site, while Marketing tests the campaign pages. This assumes the second path already exists. If it doesn't, option 4 is how you get one without a dev ticket.

Hosted Pages serves a full copy of a page from its own URL on your domain, with your edits already built into the HTML. That gives you the second path option 3 needs without asking your web team to duplicate a template, and the other platform keeps the original untouched.

Because Tailor serves the page rather than editing it in the visitor's browser, there is also no client-side edit for the other platform's script to collide with.

Best when: You want path separation but creating the duplicate page yourself is the blocker, or you want the tailored version rendered server-side. A hosted page is frozen at the moment it was cloned, so later changes to the original do not reach it.

Most testing platforms expose the visitor's assignment on a global JavaScript object, and server-side tests can do the same. Tailor can use that to skip the conflicting test for those visitors, so only one platform ever modifies the page. Check your platform's docs for the exact global, since the name and shape differ between vendors and versions.

Tailor does not read an arbitrary variable off the page by itself. There are two ways to get your assignment into its targeting:

• Put it in the URL. The simplest path. Your app adds the assignment as a parameter, and Tailor targets on it exactly like options 1 and 2.
• Use a custom signal. We add a small check to your account that runs on the page, reads your variable, and answers yes or no. You then target on that answer. Yes or no only today, so you get one signal per assignment you want to carve out.

// 1. Your app sets this before the Tailor tag runs.
window.myExperiments = { pricing_test: "treatment" };

// 2. We add a custom signal on your account that reads it
//    and answers yes or no:
return window.myExperiments?.pricing_test === "treatment";

// 3. You target the Tailor test on that answer.

Best when: The tests genuinely overlap on the same page and you still want both running at full traffic. This is the most precise option and the one that needs the most setup, because the signal has to be added to your account before you can target on it. Send us the variable you can expose and we'll set it up with you.

Make your other platform wait for Tailor. If Tailor is testing the page, the other platform never starts. If not, it starts as usual. Switch the other platform to manual activation on the pages you both test, then add this after its snippet:

(window.TailorQueue || (window.TailorQueue = [])).push(async function () {
  if (await Tailor.isTailored()) return; // Tailor is testing this page. The other platform stays off.

  // Start the other platform. Swap in its own manual activation call.
  window.otherPlatform = window.otherPlatform || [];
  window.otherPlatform.push(["activate"]);
});

Best when: Your other platform tests the same pages as Tailor. Avoid delaying the platform's whole script instead: all of its tests would flicker, including ones Tailor never touches.