If you have set ABTestly to deferred consent with a consentKey,
the snippet waits for window[consentKey] === 'granted' before it
does anything. If your CMP is not flipping that flag the way ABTestly
expects, the snippet just… waits. Forever. Silently.
The check ABTestly does
The exact string 'granted', on the exact top-level property named
by consentKey. Anything else is a no.
Common breakage
Wrong value. Your CMP writes true, or 'accepted', or 1.
ABTestly wants literally 'granted'.
Wrong key. Your CMP writes to window.cookieConsent.status = 'granted' (a nested path). ABTestly reads window[consentKey]
directly, no path resolution.
Property redefined with a getter. Some CMPs use
Object.defineProperty with a getter. ABTestly’s polling reads the
property, which invokes the getter, so this actually works fine.
unless the getter throws.
Property set inside an iframe. ABTestly reads the top-level
window. A CMP that lives in an iframe and sets the flag on the
iframe’s window does not reach the outer.
Debugging
Open DevTools on a fresh page load, before the CMP has fired:
If it returns undefined, the key is not set on window at all.
Wait for the CMP to fire, then re-run.
If it returns anything other than 'granted', ABTestly will not
fire.
The bridge pattern
If your CMP does something other than “assign 'granted' to a
top-level window property”, write a small bridge that turns its real
event into ABTestly’s expected flag:
Install this bridge directly on your site, in your page code or your
tag manager or CMP integration, and load it before the ABTestly
snippet. Do not place it in ABTestly Global JS. In deferred mode
ABTestly makes no request and does not load Global JS until consent is
already granted, so a bridge placed there would load too late to ever
signal the grant.
Then set ABTestly’s consentKey to 'abtestlyConsent' in
Settings → Snippet. The bridge translates your CMP’s real event into
ABTestly’s expected flag.
The fail-closed default
If consentKey is empty in your snippet, because deferred mode was
turned on but no key was set, the snippet logs an error and does
nothing. That is the safe default; ABTestly will never fire without
explicit consent.
Check the DevTools Console for:
If you see it, either set the key in your dashboard, or turn off
deferred mode.
When “consent stuck” is actually opt-out
An opted-out visitor also does not fire the snippet, but the reason
is opt-out, not consent. Check for the cookie:
If it says __abtestly_optout=1, the visitor is opted out. That is
working as designed. Have them visit
https://yoursite.com/?abtestly_optout=0 to opt back in. Last modified on August 25, 2026
