2025 Yottaa Web Performance Index

Q1 2025

A dashboard that analyzes over 500 million visits from 1,300+ top eCommerce sites, offering key benchmarks and insights on third-party applications, their impact on web performance and results of site optimization through app sequencing. 

Key Findings

The data is clear - small improvements drive big results for eCommerce brands and retailers.

+3% Mobile Conversions

Saving one second boosts mobile conversion by 3% on your current conversion rate. A 5% conversion rate would rise to 5.15%.

63% Bounce Rate

Pages loading longer than 4 seconds see bounce rates skyrocket to 63%

1.9 Seconds

Sequencing apps to optimize product detail pages (PDPs) trims nearly two seconds from page load times.

>1% Conversion Deficit

The average red-rated third-party app performance hit reduces conversions by 0.29%, with multiple apps adding up to >1% conversion deficit. See app ratings below.

44% Page Load Time

Third-party apps account for nearly half of a site’s total load time

Speed = Revenue

Save a Second, Increase Sales by 3%

Seconds Saved = Revenue Earned: Each second you shave off page load times reduces bounce rates and increases conversions.
First Impressions Matter: Shoppers decide whether to stay or leave with the very first screen.

Benchmark your site against your peers

A Fast Track to Conversion

The trend is clear – as pages slow, conversion rates fall, and bounce rates rise. On average, 63% of visitors bounce when page load times exceed 4 seconds. In contrast, 45% of visitors, on average, bounce from sites that load in 4 seconds or less.

Specific Page Visits Matter

Shoppers are clear about where they spend their time: 70% of visits happen on category or product listing pages.

Page Load Savings Add Up to Online Sales

By improving these critical pages, you can turn seconds into dollars. Shaving 2 seconds off load times boosts conversions and reduces shopper frustration. Smoother, faster transitions between frequently visited pages keep shoppers engaged, driving more revenue.

Fast Pages Engage Shoppers

Fast pages engage shoppers while slow pages drive them away. Bounce rates spike at 4-second loads, while conversions thrive at 3.3–3.5 seconds across mobile and desktop.

Deep Site Engagement Drive Online Sales

Speed drives action: Fast sites keep shoppers exploring. On mobile, cutting 1 second per page boosts visits from 1 page to 12, fueling deep engagement and conversions.

Key Insights

Accelerate growth by cutting friction, not functionality. Optimize load times by fixing bottlenecks, caching resources, and sequencing third-party apps to transform the shopper journey

Shave Seconds Off to Boost Conversions

Optimizations cut page loads by nearly 2 seconds, reducing bounce rates by 8% and boosting mobile conversions by 3% per second saved.

Prioritize High-Impact Pages

PDPs and category pages make up 70% of views, but don’t ignore key touchpoints like landing pages, which are vital for converting paid traffic and improving return on ad spend (ROAS).

Don’t Underestimate The Cost of Slow Pages

Shoppers demand speed: pages loading over 4 seconds see bounce rates hit 63%, and conversions drop 22%.

Ready to Boost Your Web Performance?

Don’t let slow load times and poor site performance hold you back. Get started with Yottaa today.

Optimizing Mobile Pages is Key

Mobile dominates across verticals, with over 80% of traffic coming from mobile devices in luxury apparel and health and beauty. This makes mobile optimization a top priority for brands in these sectors.

Optimization Impact Varies per Vertical per Device

Different industries use different features from third parties to improve their Rate Per Visitor; all those vendor’s apps need optimization.

Browsers and Buyers in Each Vertical Go Deep

Across all verticals, buyers explore 11+ pages per session vs. 5-6 for browsers, boosting both add-to-cart chances and average order value (AOV) with engaging, optimized sites.

Bounce Rates per Vertical and per Device

Long page loads lead to bounces across devices, but the stakes differ by industry. High-consideration items like a $2,000 refrigerator might tempt eCommerce leaders to think their shoppers will wait, while those selling commoditized goods, like $10 lip gloss, know speedy performance is critical to compete with giants like Amazon.

Key Insights

Mobile traffic dominates in multiple verticals

Mobile traffic accounts for the majority of all traffic across all verticals, especially for health and beauty and luxury apparel verticals with over 80% of all traffic to their sites.

Deep engagement across pages

Browsers and buyers engage deeply, viewing an average of 5-6 pages for browsers and at least 11 pages for buyers across all verticals and devices, highlighting the importance of  lightning-fast page load times.

Slow load times drive bounces

Bounce rates for both buyers and browsers remain consistently high across verticals for pages that take longer than 4 seconds to load, underscoring the need for performance optimizations to retain visitors.

Benchmark your site against your peers

Third Party Page Load is Critical to Performance

Third parties contribute to functionality but often at a cost to performance. 44% of page load time is tied to third-party apps.

Average Number of Tags per Page Type

Third-party tags are busiest on product detail (56) and category pages (53) vs. home pages (49), reflecting tailored tools like product recommendations and personalization features driving engagement where it matters most.

Not All Third Parties are Created Equal

Yottaa’s Performance Impact Rating (PIR) analyzes each third-party technology, assigning each a color rating:

  • Green-rated apps cause little performance impact, working seamlessly with minimal delays
  • Yellow-rated apps may cause occasional slowdowns, but typically don’t disrupt the shopper’s ability to convert
  • Red-rated apps cause significant drag, adding disruption and friction to the shopper journey

Conversion Impact by Color

Slow apps hurt sales. Each bad app adds 100ms to load time and cuts conversions by 0.29%. Just five bad apps can drop conversions by 1%, costing a $100M retailer $1M.

Understanding the Performance Impact Rating (PIR)

Evaluating adoption, functionality, and PIR scores of the apps helps create a fast, seamless shopping experience that boosts conversions:

  • UGC/reviews and personalization: Essential for PDPs but prone to slowdowns due to low PIR scores. Optimizing them is key.
  • Shipping and fulfillment tools: High PIR scores ensure minimal impact on checkout and confirmation pages while delivering crucial functionality.
  • Site tools and coupons: Enhance shopper experiences with strong PIR scores and minimal impact.

Key Insights

​​Your third-party apps can decrease sales

A typical third-party technology adds 69ms to page load time. On average, red-rated apps (see app ratings below) delay pages by 98ms, contributing to a 0.29% reduction in conversions.

Deficits compound across the stack

With third-party technologies accounting for nearly 44% of page load time, the delays quickly add up.

Slow pages mean lost opportunities

Pages that take more than 4 seconds to load experience a bounce rate of 63% – 17 percentage points higher than faster pages. These slow loads waste 1 in 6 visits and reduce conversion rates by 22%.

Yottaa’s Performance Impact Rating (PIR) is a proprietary metric designed to quantify the impact of third-party vendors on e-commerce website performance. While the exact algorithm isn’t publicly disclosed in minute detail, here’s a breakdown of how it’s calculated based on Yottaa’s documentation and reports:

Core Concept

The PIR score aims to provide a standardized way to compare the performance impact of different third-party technologies. It essentially measures how much a third-party vendor contributes to delays and performance risks on a website.

Key Factors in the PIR Calculation

Page Delay Violations: This refers to instances where a third-party vendor causes significant delays in page loading. This can include:

 

  • Long loading times: The time it takes for the third-party’s resources (scripts, images, etc.) to load.
  • Blocking resources: When a third-party script blocks the rendering of other page elements, causing delays in visual display.
  • Performance Risk Violations: This encompasses various performance issues that a third party can introduce, such as:
    • Excessive resource usage: The amount of bandwidth, CPU, or memory consumed by the third party.
    • JavaScript errors: Errors caused by the third-party’s scripts that can disrupt page functionality.
    • Layout shifts: Changes in the layout of the page caused by the third-party’s elements loading asynchronously.
    • Total Resources Loaded: This is the total number of resources (scripts, images, etc.) loaded by the third-party vendor. This factor is used to normalize the PIR score, taking into account the complexity of the third party.

PIR Calculation

PIR = (Total Page Delay Violations + Total Performance Risk Violations) / Total Resources Loaded

Interpretation of PIR Scores

Lower PIR is better: A lower PIR score indicates that the third party has a smaller impact on website performance.
Color-coded ratings: Yottaa often uses a color-coding system to represent PIR scores:

 

  • Green: Indicates a low performance impact.
  • Yellow: Indicates a moderate performance impact.
  • Red: Indicates a significant negative impact on performance.

Key Considerations

Context matters: The PIR score should be considered in the context of the specific website and its performance goals. A third party with a moderate PIR might be acceptable if its functionality is crucial for the business.

Dynamic metric: The PIR score can change over time as third-party vendors update their code or as website configurations change.

Yottaa’s expertise: Yottaa’s deep understanding of e-commerce performance and their extensive data on third-party vendors contribute to the accuracy and relevance of the PIR.

In summary, Yottaa’s PIR is a valuable metric for evaluating the performance impact of third-party vendors on e-commerce websites. By considering page delay violations, performance risk violations, and the total resources loaded, the PIR provides a standardized way to compare different vendors and make informed decisions about technology choices.

Explore the Yottaa Web Performance Index

The list below highlights the top third-party technologies used across the Yottaa community of eCommerce sites, sorted alphabetically. Use the search bar to filter by name, category, or rating to find the insights you need.

Represents a consistent negative performance impact. 15% of technologies earned a Red rating.

Represents an inconsistent negative performance impact. 47% of technologies earned a Yellow rating.

Represents little or no performance impact. 38% of technologies earned a Green rating.

Final Thoughts

In the race for shopper attention and conversion, every second counts. Prioritizing speed doesn’t mean sacrificing functionality – it means creating an optimized experience that respects the shopper’s time and journey.

By addressing performance bottlenecks and leveraging smart optimizations, you can transform wasted visits into meaningful engagements, turning speed into a powerful competitive advantage. Now is the time to seize your second’s chance and unlock the full potential of your eCommerce site.

Ready to Boost Your Web Performance?
Don’t let slow load times and poor site performance hold you back. Get started with Yottaa today.

About the Data

2025 Yottaa Web Performance Index provides insights on eCommerce site speed, performance, and third party impact, based on activity from September and October 2024. It includes data from over ½ billion visits, 1,300+ sites, and 600+ third-party technologies from the Yottaa platform, with strict aggregation measures to ensure credibility. The index does not reflect Yottaa’s operational performance or financial metrics, and the results are not a guarantee of site performance.

These benchmarks cover same-site activity from September and October 2024. The third-party benchmarks cover September 2024.

We use strict aggregation measures to ensure anonymity and to present credible and reliable information. These measures include requirements for analysis set size, diversity, and consistency.

The data may not be exact due to rounding.

The Site Performance Index includes activity across more than:

  • ½ billion ecommerce visits
  • 1,300+ leading eCommerce sites
  • 600+ leading third-party technologies

The Site Performance Index does not directly indicate the operational performance of Yottaa or its reported financial metrics. The performance metrics shared within this report are calculated based on the analysis set and are not a guarantee of site performance.

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