#Japan #E-Commerce #Chiyoda #Core Web Vitals #Load Speed

E-Commerce Site Load Speed Rankings – April 2026

In April 2026, Gaprise Inc., a leading overseas SaaS trading company based in Chiyoda, Tokyo, announced the latest rankings for e-commerce site load speeds in Japan, focusing on 456 online retailers.

Overview of the Research

Research Period

The data was collected as of April 2026.

Research Organization

This study was conducted by Gaprise Inc.

Target Companies

The research surveyed the websites of the top 300 companies from the 85th catalog and correspondence sales ranking published by the E-commerce Newspaper.

Research Methodology

Utilizing Google’s Chrome User Experience Report's official datasets, this evaluation compared the Largest Contentful Paint (LCP) metrics for each site at the domain level using 4G connections on mobile devices. For more details, the data can be accessed here.

Understanding LCP (Largest Contentful Paint)

LCP refers to the time taken for the largest visual content element on a web page to load and be displayed. It is a vital component of Google’s Core Web Vitals. A lower LCP value indicates a faster perceived load time, enhancing user experience.

Google has set the threshold for a good user experience at an LCP of 2.5 seconds; anything over 4 seconds is considered poor. A case study from Renault indicates that significant improvements can bring LCP under 1 second.

Top 10 Rankings

Here are highlights from the latest performance survey:

• - The top 10 e-commerce platforms managed to achieve load speeds of under 0.8 seconds.
• - The standout performer is 'Mandarake', with a stellar LCP of 0.515 seconds and a TTFB (Time to First Byte) of 0.138 seconds.
• - 'Shirohato' maintained its second position with an LCP of 0.610 seconds, alongside familiar names like 'Youko', 'AmiAmi', 'Hiraki', and 'Epson Direct', which continue to demonstrate robust performance.

Performance Insights

Approximately 80% of the surveyed 456 websites achieved 'GOOD' status by having an LCP under 2.5 seconds. With this survey expanding to encompass top performers from the 85th catalog ranking, it illustrates the recognition among e-commerce sites of the critical importance of display speed.

Notably, 141 sites beat major players like Amazon (ranked 142nd with an LCP of 1.504 seconds), Yodobashi.com (125th with 1.451 seconds), and BicCamera (116th with 1.415 seconds). As consumer expectations regarding load speed increase, sites with LCPs exceeding 2 seconds are increasingly regarded as slow. As such, sites aiming to convert visits must prioritize competitive benchmarks against leaders rather than the industry average.

The Impact of TTFB

An evident trend from this data is the stark difference in server response times (TTFB) between top and lower performers. Most sites achieving an LCP of under 1 second also maintained TTFB below 0.5 seconds. Optimizing front-end elements alone is insufficient to break the 1-second LCP barrier; the design of backend infrastructure is a crucial factor for competitive advantage.

Noteworthy INP Metrics

The top performers in the new Core Web Vitals metric, Interaction to Next Paint (INP), include:

• - Gram Style’s official B2B wholesaler (0.043 seconds).
• - Notable mentions are 'Nelies', a specialized English teaching materials store, and 'Shirohato', both achieving impressive rankings in LCP.

INP measures the responsiveness of web pages to user interactions, and analyzing it alongside LCP can provide a comprehensive performance evaluation.

Continuous Improvement Strategies

Companies improving their scores generally do so through:

• - JavaScript execution optimization.
• - Efficient event handler implementation.
• - Enhanced rendering performance.

To enhance both LCP and INP, sustained improvements and the correct adoption of technology are critical factors.

For comprehensive data on all 456 analyzed sites and successful case studies of LCP improvement, details are available on our media platform, MarTechLab.

About Gaprise Inc.

Founded in January 2005, Gaprise is a SaaS trading company dedicated to discovering cutting-edge overseas technologies and facilitating their integration into the Japanese market. With alliances spanning globally recognized tech firms, we support a wide array of business growth facets, including digital marketing, customer experience optimization, and AI utilization.

As Japan's enterprise IT market is projected to reach approximately 30 trillion yen, and with the SaaS market continuing to expand, Gaprise aspires to bridge innovative technologies with Japanese businesses, contributing to value creation in this growing landscape.