Switching from Plausible or Fathom

Before you upload

1. Create your site in Klar and follow the installation guide. Tracker installation guide
2. Note the first day Klar collected data for that site. Your import should end before that day.
3. Prepare the export described below for your current provider, then open Import settings for the correct site. Import settings
4. Check the reported range and imported totals after the upload. Keep the original export so you can check discrepancies.

Choosing a migration path

Use the From Plausible or From Fathom section below. If you are still comparing tools, read:

• Klar and Plausible
• Klar and Fathom
• Klar and Google Analytics
• Klar pricing

Install Klar on your site

What comes across

From a Plausible export, Klar imports day by day:

• Pages, with their pageview counts.
• Sources, and UTM source, medium and campaign. UTM values that differ only by letter case are shown as one row. Any UTM values present in the supported export columns are retained.
• Countries.
• Devices, browsers and operating systems.
• Daily unique visitors, from the export's visitors file.

What doesn't come across:

• Entry and exit pages.
• Custom events and goals.
• Bounce rate and visit duration: both cover Klar-tracked visits only.
• Regions and cities, and UTM term and content.

Imported unique visitors are Plausible's daily unique visitors, summed day by day, the way Klar aggregates imported daily totals. So someone who visited on two different days counts twice over a longer range. The new/returning split covers only visitors Klar tracked itself, and imported days are left out of funnels: an export carries counts, not visitor identities. Imported rows never count toward your monthly pageview quota.

A Fathom export carries pages and their daily pageviews only, so that is what a Fathom import brings.

Import up to the day you installed Klar, not past it

If Klar has already been collecting on this site, don't import a range that overlaps that period. Imported rows and collected rows are both real rows, and every chart counts both — so an overlapping range shows those days twice, visitors included, which makes the doubling easy to mistake for a good week.

By default, Klar refuses an overlapping upload rather than silently merging it. When the overlap is with collected data and an earlier range can be imported, it offers to import only the days before collection began. Take the offer: the part of your history Klar was never running for is exactly the part worth bringing over.

From Plausible

1. Prepare the full Plausible data export as a zip containing the day-by-day CSV files.
2. Keep the original filenames, such as imported_pages, imported_sources and imported_visitors. Klar also accepts their date-suffixed filenames.
3. Upload the zip on the Import page, under the Plausible tab.

A summary report without a day-by-day breakdown cannot place your history accurately on the timeline. Use the full export with dated rows instead.

From Fathom

1. Prepare a CSV of pageviews broken down by pathname and day.
2. Each row must identify a date, pathname and pageview count; Klar recognizes Fathom columns such as Date, Pathname and Views.
3. Upload the CSV on the Import page, under the Fathom tab.

A zip can also be used when it contains a supported page-by-day CSV. Totals without dates cannot be imported into the correct days.

After importing

Re-uploading an export replaces the previous import from the same tool (Plausible or Fathom) instead of adding to it. The swap happens only once the new upload has finished: if it fails partway, the previous import stays as it was, so a retry after a mistake is safe. You can delete an import at any time from the Import page — that removes every pageview it added along with it.

If an earlier import shows no UTM or visitor data, upload the file again.