September 2025 Theme Vitals Update
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The Chrome User Experience Report (CrUX) data for September 2025 is now live on Theme Vitals. Overall Shopify performance is down on mobile, and Horizon has plateaued for now.
In this post, I’ll cover:
- Change in the data population
- Shopify overall performance changes
- Update on new flagship Shopify theme Horizon
- Most improved themes for web performance
- Highest growth themes in market share
- New features
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Change in data population
- The total number of Shopify websites increased by 0.02% on both mobile (~12K) and desktop (~6K).
- New themes added this month were Haven, Flex, and Elysian.
- The Seasons and Couture themes were dropped due to lack of data.
- I now show 317 (up from 316) total themes. 221 have performance data for mobile devices and 188 for desktop devices.
Shopify overall performance changes
Here are the median, min, and max performance numbers on mobile for all the Shopify themes measured on mobile devices:
(For a more accessible version, see it live on the website: Aggregations).
Mobile performance dipped by 1.1 percentage points and improved on desktop by 0.75 percentage points. The dip on mobile was mostly driven by a drop in largest contentful paint (LCP) performance.
Update on new flagship Shopify theme Horizon
Horizon is still struggling and seems to have plateaued for now. This is driven mostly by LCP and INP which are arguably the 2 most important web vitals metrics. On mobile, it is ranked 208th out of 221 themes with data. It's doing a bit better on desktop at 40th out of 188.
This is unfortunate as Horizon is now the 2nd-fastest growing theme in installs after Dawn. We will eventually see it pulling down Shopify's overall performance numbers.
Here's the mobile performance data for this month:
See full data on the Horizon theme page.
All of the Horizon variations are now in the rankings, and all perform similarly to Horizon.
Most improved themes
For mobile devices, these themes had the most improvement in passing all Core Web Vitals - all are in the Horizon family:
- Ira: 8.9 points (67 origins)
- Fabric: 7.3 points (425 origins)
- Effortless: 7.1 points (105 origins)
- Handy: 7.1 points (90 origins)
- Ritual: 6.5 points (158 origins)
For desktop devices, these themes improved the most:
- Flux: 12.3 points (81 origins)
- Whisk: 10.3 points (113 origins)
- Forge: 7.1 points (58 origins)
- Sydney: 7.1 points (59 origins)
- Monaco: 6.8 points (66 origins)
When themes on these lists have a small number of origins/market share, some of the improvements could be due to the underlying population of websites changing.
Highest market growth
As a reminder, the market share numbers calculated in Theme Vitals are not the same as number of installs. Here, we’re calculating market share based on the number of origins (websites/domains) in CrUX. CrUX only shares data for websites that reach a certain threshold of popularity. This threshold sometimes changes. To learn more, check out the methodology page for CrUX.
Growth in number of origins
The themes that already have the largest market shares usually have the highest growth in number of origins. This is the first time that the new flagship theme Horizon has broken into the top 5.
Mobile
Only Rise and Prestige are non-flagship themes:
- Dawn: 2348
- Horizon: 810
- Rise: 357
- Prestige: 282
- Savor: 220
Desktop
Only Prestige and Concept are non-flagship:
- Dawn: 963
- Prestige: 273
- Horizon: 234
- Concept: 167
- Craft: 134
Percent growth in origins
Raw growth is interesting but usually focuses too much on the existing themes with high market share. Here, I show which themes are growing the fastest on a percentage basis. It's no surprise that Horizon is leading here.
Mobile
All are Horizon variations except Rise:
- Rise: 49.0%
- Horizon: 48.8%
- Atelier: 43.1%
- Heritage: 40.2%
- Savor: 39.8%
Desktop
All are Horizon variations:
- Atelier: 56.7%
- Pitch: 56.3%
- Dwell: 51.3%
- Fabric: 44.7%
- Horizon: 41.7%
New features
We have a number of new features this month!
- Fastest themes page - a helpful one-stop-shop for the highest performing themes that is targeted to less technical users
- Top performer tag - themes that are in the top 25 for performance on BOTH mobile and desktop now get a "top performer" tag on the all themes page and individual theme pages
- Letter grades - On the individual theme pages, another feature for less technical people to more quickly understand the meaning behind the percent passing Core Web Vitals numbers. These use the standard US grading system, e.g., 90-100% is an "A".
Closing
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As always, if you have ideas for new features or other improvements, let me know!