AEM Edge Delivery Services Experimentation

The AEM Experimentation plugin helps you quickly set up experimentation and segmentation on your AEM project. It is currently available to customers in collaboration with AEM Engineering via co-innovation VIP Projects. To implement experimentation or personalization use-cases, please reach out to the AEM Engineering team in the Slack channel dedicated to your project.

Features

The AEM Experimentation plugin supports:

👥 serving different content variations to different audiences, including custom audience definitions for your project that can be either resolved directly in-browser or against a trusted backend API.
💸 serving different content variations based on marketing campaigns you are running, so that you can easily track email and/or social campaigns
📈 running A/B test experiments on a set of variants to measure and improve the conversion on your site. This works particularly with our 💹 RUM conversion tracking plugin.
🚀 easy simulation of each experience and basic reporting leveraging in-page overlays

Installation

Add the plugin to your AEM project by running:

git subtree add --squash --prefix plugins/experimentation git@github.com:adobe/aem-experimentation.git main

If you later want to pull the latest changes and update your local copy of the plugin

git subtree pull --squash --prefix plugins/experimentation git@github.com:adobe/aem-experimentation.git main

If you prefer using https links you'd replace git@github.com:adobe/aem-experimentation.git in the above commands by https://github.com/adobe/aem-experimentation.git.

Project instrumentation

On top of a regular boilerplate project

Typically, you'd know you don't have the plugin system if you don't see a reference to window.aem.plugins or window.hlx.plugins in your scripts.js. In that case, you can still manually instrument this plugin in your project by falling back to a more manual instrumentation. To properly connect and configure the plugin for your project, you'll need to edit your scripts.js in your AEM project and add the following:

at the start of the file:

const experimentationConfig = {
  prodHost: 'www.my-site.com',
  audiences: {
    mobile: () => window.innerWidth < 600,
    desktop: () => window.innerWidth >= 600,
    // define your custom audiences here as needed
  }
};

let runExperimentation;
let showExperimentationOverlay;
const isExperimentationEnabled = document.head.querySelector('[name^="experiment"],[name^="campaign-"],[name^="audience-"]')
    || [...document.querySelectorAll('.section-metadata div')].some((d) => d.textContent.match(/Experiment|Campaign|Audience/i));
if (isExperimentationEnabled) {
   const {
    loadEager: runExperimentation,
    loadLazy: showExperimentationOverlay,
   } = await import('../plugins/experimentation/src/index.js');
}

Early in the loadEager method you'll need to add:

async function loadEager(doc) {
  …
  // Add below snippet early in the eager phase
  if (runExperimentation) {
    await runExperimentation(document, experimentationConfig);
  }
  …
}

This needs to be done as early as possible since this will be blocking the eager phase and impacting your LCP, so we want this to execute as soon as possible.

Finally at the end of the loadLazy method you'll have to add:

async function loadLazy(doc) {
  …
  // Add below snippet at the end of the lazy phase
  if (showExperimentationOverlay) {
    await showExperimentationOverlay(document, experimentationConfig);
  }
}

This is mostly used for the authoring overlay, and as such isn't essential to the page rendering, so having it at the end of the lazy phase is good enough.

On top of the plugin system

The easiest way to add the plugin is if your project is set up with the plugin system extension in the boilerplate. You'll know you have it if either window.aem.plugins or window.hlx.plugins is defined on your page.

If you don't have it, you can follow the proposal in adobe/aem-lib#23 and adobe/aem-boilerplate#275 and apply the changes to your aem.js/lib-franklin.js and scripts.js.

Once you have confirmed this, you'll need to edit your scripts.js in your AEM project and add the following at the start of the file:

const experimentationConfig = {
  prodHost: 'www.my-site.com',
  audiences: {
    mobile: () => window.innerWidth < 600,
    desktop: () => window.innerWidth >= 600,
    // define your custom audiences here as needed
  }
};

window.aem.plugins.add('experimentation', { // use window.hlx instead of your project has this
  condition: () =>
    // page level metadata
    document.head.querySelector('[name^="experiment"],[name^="campaign-"],[name^="audience-"]')
    // decorated section metadata
    || document.querySelector('.section[class*=experiment],.section[class*=audience],.section[class*=campaign]')
    // undecorated section metadata
    || [...document.querySelectorAll('.section-metadata div')].some((d) => d.textContent.match(/Experiment|Campaign|Audience/i)),
  options: experimentationConfig,
  url: '/plugins/experimentation/src/index.js',
});

Increasing sampling rate for low traffic pages

When running experiments during short periods (i.e. a few days or 2 weeks) or on low-traffic pages (<100K page views a month), it is unlikely that you'll reach statistical significance on your tests with the default RUM sampling. For those use cases, we recommend adjusting the sampling rate for the pages in question to 1 out of 10 instead of the default 1 out of 100 visits.

Edit your html <head> and set configure the RUM sampling like:

<meta name="experiment" content="...">
...
<!-- insert this script tag before loading aem.js or lib-franklin.js -->
<script>
  window.RUM_SAMPLING_RATE = document.head.querySelector('[name^="experiment"],[name^="campaign-"],[name^="audience-"]')
    || [...document.querySelectorAll('.section-metadata div')].some((d) => d.textContent.match(/Experiment|Campaign|Audience/i))
    ? 10
    : 100;
</script>
<script type="module" src="/scripts/aem.js"></script>
<script type="module" src="/scripts/scripts.js"></script>

Then double-check your aem.js file around line 20 and look for:

const weight = new URLSearchParams(window.location.search).get('rum') === 'on' ? 1 : defaultSamplingRate;

If this is not present, please apply the following changes to the file: https://github.com/adobe/helix-rum-js/pull/159/files#diff-bfe9874d239014961b1ae4e89875a6155667db834a410aaaa2ebe3cf89820556

Custom options

There are various aspects of the plugin that you can configure via options you are passing to the 2 main methods above (runEager/runLazy). You have already seen the audiences option in the examples above, but here is the full list we support:

runEager.call(document, {
  // Lets you configure the prod environment.
  // (prod environments do not get the pill overlay)
  prodHost: 'www.my-website.com',
  // if you have several, or need more complex logic to toggle pill overlay, you can use
  isProd: () => !window.location.hostname.endsWith('hlx.page')
    && window.location.hostname !== ('localhost'),

  // the storage type used to persist data between page views
  // (for instance to remember what variant in an experiment the user was served)
  storage: window.SessionStorage,

  /* Audiences related properties */
  // See more details on the dedicated Audiences page linked below
  audiences: {},
  audiencesMetaTagPrefix: 'audience',
  audiencesQueryParameter: 'audience',

  /* Campaigns related properties */
  // See more details on the dedicated Campaigns page linked below
  campaignsMetaTagPrefix: 'campaign',
  campaignsQueryParameter: 'campaign',

  /* Experimentation related properties */
  // See more details on the dedicated Experiments page linked below
  experimentsMetaTagPrefix: 'experiment',
  experimentsQueryParameter: 'experiment',

  /* Fragment experiment needs redecoration */
  // See more details below
  decorationFunction: (el) => {
    /* handle custom decoration here, for example: */
    buildBlock(el);
    decorateBlock(el);
  }
});

For detailed implementation instructions on the different features, please read the dedicated pages we have on those topics:

Audiences
Campaigns
Experiments

Cases of passing decorationFunction Fragment replacement is handled by async observer, which may execute before or after default decoration complete. So, you need to provide a decoration method to redecorate. There are several common cases:

Have a selector for an element inside a block and the block needs to be redecorated => sample code above
Have a .block selector and need to redecorate => switch block status to "loading" and call loadBlock(el)
Have a .section selector and need to redecorate => call decorateBlocks(el)
Have a main selector and need to redecorate => call decorateMain(el)

Extensibility & integrations

If you need to further integrate the experimentation plugin with custom analytics reporting or other 3rd-party libraries, you can listen for the aem:experimentation event:

document.addEventListener('aem:experimentation', (ev) => console.log(ev.detail));

The event details will contain one of 3 possible sets of properties:

For experiments:
- type: experiment
- element: the DOM element that was modified
- experiment: the experiment name
- variant: the variant name that was served
For audiences:
- type: audience
- element: the DOM element that was modified
- audience: the audience that was resolved
For campaigns:
- type: campaign
- element: the DOM element that was modified
- campaign: the campaign that was resolved

Additionally, you can leverage the following global JS objects window.hlx.experiments, window.hlx.audiences and window.hlx.campaigns. Those will each be an array of objects containing:

type: one of page, section or fragment
el: the DOM element that was modified
servedExperience: the URL for the content that was inlined for that experience
config: an object containing the config details

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README.md

README.md

AEM Edge Delivery Services Experimentation

Features

Installation

Project instrumentation

On top of a regular boilerplate project

On top of the plugin system

Increasing sampling rate for low traffic pages

Custom options

Extensibility & integrations

Files

README.md

Latest commit

History

README.md

File metadata and controls

AEM Edge Delivery Services Experimentation

Features

Installation

Project instrumentation

On top of a regular boilerplate project

On top of the plugin system

Increasing sampling rate for low traffic pages

Custom options

Extensibility & integrations