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Variant ID/Name within custom variable

lorenzonannini 06-20-16

Variant ID/Name within custom variable

Hi all,


I am trying to pass my Optimizely Campaign and Variation IDs into a custom variable that I will then be able to read from my Google Analytics tag and fire within it. Unfortunately, the way our Optimizely code is integrated is not standard and therefore I can't make use of the out of the box Optimizely/Google Analytics integration (tried it and it doesn't work).


What I would like to obtain is a variable with my:

  • Campaign/Test ID (or name)
  • Variant ID (or name)

something like: 

var abtest = campaign_id + ' - ' + variant_id;

Is there a way that I can refer the campaign id and the variant ID from within Optimizely?


Many thanks

CouchPsycho 06-20-16

Re: Variant ID/Name within custom variable


interesting issue. How about setting them within the code-editor? If you try to access a variable from without your experiment like i think you won't receive correct data. Just imagine, you have more than one experiment running. I haven't found anything within the documentation, so maybe a pro can help out.

But take into account, that -if done manually- you can set values which are non-cryptic, which will allow your analytics team to understand the values they see more easily. IDs are nice as long as you can easily translate them....

Kind regards


robertchan 06-21-16

Re: Variant ID/Name within custom variable

Hi @lorenzonannini, yes, you can get the information you requested and more using Optimizely's data object. For the numbers you wanted, I wrote a little work around. You can use what I wrote as a start:


if(document.URL.indexOf('optimizely_x') > -1){
	var experimentID = '', oIdx = document.URL.indexOf('optimizely_x');
	var idSt = oIdx+12, idEnd = oIdx+22, idIdx = oIdx+23;
	for(var i=idSt; i<idEnd; i++){ experimentID += document.URL[i]; }
	experimentID = parseInt(experimentID)
	console.log('This is experiment ID ' + typeof experimentID + ' ' + experimentID + ' running on variant index number ' + document.URL[parseInt(idIdx)]);
} else {
	console.log('Experiment ID not found. Please manually input.');

	experimentTitle =

	console.log('Currently on Optimizely revision number ' + optimizely.revision);
	console.log('The experiment name is: ' + experimentTitle);

//Requested abtest variable
var abtest = experimentID + ' - ' + document.URL[parseInt(idIdx)];
console.log('abtest = ' + abtest);

It's very important to note that this code will only work with the preview URL under the assumption that optimizely_x is found within the URL, or using a force preview link (e.g. You'll likely want to tweak the code to exactly what you're looking for, but I thought this might be a good start.

Robert Chan

Experimentation Hero

Re: Variant ID/Name within custom variable

Hi @robertchan


The approach sounds good, but I am specifically try to make it work in a production environment (i.e. without the query string parameters in the URL). Is there any variable defined/definable from Optimizely that I can set with the experiment and variation ID?


Many thanks

robertchan 06-22-16

Re: Variant ID/Name within custom variable

Hi @lorenzonannini, you can have a look at the Optimizely data object. Have a look here:


Assuming you're able to use ECMAScript 5 in production, you can do the following for what you're looking for:


//Returns (as defined by Optimizely) a hash table whose keys are the experiment ids of experiments running for the visitor
const vMap = window['optimizely'].data.state.variationMap;

//Returns the experiment ID
const eID = parseInt(Object.keys(vMap));

//Returns the variant index
const vIdx = vMap[eID];
Robert Chan

Experimentation Hero