AEM Sites Optimizer What Adobe's tool finds, fixes and leaves open in the Core Web Vitals
With AEM Sites Optimizer, Adobe offers its own tool that detects problems on an AEM website, suggests fixes and, in the highest tier, implements them itself after approval. Core Web Vitals are one of the areas it covers. This page sets out what Sites Optimizer contributes to load time, which data it relies on and which tasks it does not take on. The information reflects Adobe's public documentation. The current version there remains authoritative.
Sources: Adobe product description and documentationNo commission from Adobe
AEM Sites Optimizer: opportunities from traffic to site health, in two tiers
Sites Optimizer sorts its findings as opportunities in categories such as Traffic, Engagement, Conversion and Site Health (overview of opportunity types). Core Web Vitals belong to Site Health. According to the product description, there are two packages: Prime detects problems and suggests fixes, Ultimate can also carry out fixes itself. Licensing is based on content requests per month, meaning requests to AEM Sites as a Cloud Service or AEM Sites Managed Services, including requests answered by an upstream CDN.
Core Web Vitals in Sites Optimizer: findings by LCP, INP and CLS with AI suggestions
The Core Web Vitals opportunity groups problems by Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift, separately for mobile devices and desktop. For each finding, the tool generates suggestions for a fix and shows an estimated traffic loss and traffic value. Code fixes can be passed on to GitHub and Jira. According to the documentation, only pages with at least 1,000 page views are analyzed.
For teams without their own performance measurement, this is progress: problems become visible per page instead of as a single score for the entire domain. The limit shows where pages have little traffic but use the same components as the heavily visited ones. A bug in a component affects every page that uses it, but it is measured only where there are enough visitors.
Data basis: Operational Telemetry as a sample, Google's assessment based on CrUX
AEM collects measurements from real visitors' browsers as Operational Telemetry. According to the Real Use Monitoring documentation, one in a hundred page views is captured by default, and the measurement knows page views but not visitors or sessions. Sites Optimizer's Core Web Vitals analyses are based on this data.
Google, by contrast, evaluates based on the Chrome User Experience Report (CrUX), over 28 days and at the 75th percentile. Both sources measure the same metrics on different segments of visitors, and their values can differ. For sign-off against target values, the Chrome User Experience Report is therefore the benchmark, and the telemetry is the daily complement. Which tools use which source is explained under Measuring Core Web Vitals.
Auto-Optimize: fixes after approval within the existing workflow
In the Ultimate tier, Sites Optimizer implements fixes itself. According to the product description, this happens only after approval. The changes land in the authoring environment and go through the existing review and publishing process. This reduces the effort for simple, content-related fixes. For code fixes, the tool prepares pull requests. Review and merge as well as changes to Dispatcher rules or the loading order of third-party scripts remain work for the development team or the implementation partner.
Sites Optimizer limits: target values, trade-offs and independent sign-off remain outside the tool
- Target values per page type. The tool reports deviations from Google's thresholds. It does not define which value contractually applies to the homepage, listing page, detail page and form.
- Trade-offs against marketing and personalization. Whether a tag, a testing tool or a personalized component is worth its cost in input responsiveness is decided not by a tool, but by an owner with a budget.
- Requirements before the project. The performance requirements for an implementation or migration belong in the requirements specification before the first component is built. Sites Optimizer measures afterwards. A template is available under AEM Performance Requirements Template.
- Independent sign-off. When the vendor's tool supplies the findings and suggests the fixes, nobody outside this chain checks whether the result reaches users.
Sites Optimizer and independent sign-off complement each other
The greatest effect comes when the findings of Sites Optimizer feed into a managed process: target values per page type and market, a prioritized backlog for the development team or the implementation partner, and sign-off of every release against Google's real-user data. How this process works for an AEM platform is described under Adobe Experience Manager Performance and Website Performance Optimization. How AEM websites in the DACH region actually perform is shown in the AEM Core Web Vitals Benchmark 2026.
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Frequently asked questions about AEM Sites Optimizer
Does AEM Sites Optimizer replace performance consulting?
No. It partly replaces troubleshooting, not the steering of the work. It finds problems with LCP, INP and CLS, suggests fixes and, in the Ultimate tier, implements them after approval. Target values per page type, the trade-off against marketing tags and personalization, and the independent sign-off of every release against Google's real-user data remain tasks outside the tool.
What data are the Core Web Vitals findings based on?
On measurements from real visitors' browsers that AEM collects as Operational Telemetry, by default as a sample of one page view in a hundred. Google, by contrast, evaluates based on the Chrome User Experience Report. Both sources measure the same metrics, but on different segments of visitors. For Google's assessment, the Chrome User Experience Report is authoritative.
Does Sites Optimizer analyze every page?
No. According to the documentation on the Core Web Vitals opportunity, only pages with at least 1,000 page views are analyzed. Pages with little traffic, such as archived detail pages or new campaign pages, are therefore left out, although they use the same components.
Can you try AEM Sites Optimizer?
Yes. Adobe offers a trial version with three opportunity types: broken backlinks, Core Web Vitals and missing alt text, each with up to three findings per opportunity per month.