Privacy

MergeStudio is designed so normal spreadsheet jobs are processed on your device. The page below separates spreadsheet processing from ordinary website hosting, analytics and optional technical error diagnostics.

🔒 Spreadsheet contents stay localNormal Excel and CSV jobs are parsed and merged inside your browser.
👤 No MergeStudio accountYou do not need to sign in or upload a workbook to an account.
🧪 Diagnostics exclude spreadsheet dataError reporting is designed around fixed technical codes, not file contents or cell values.
Normal spreadsheet jobs are not uploaded to a MergeStudio backend.

The files are read in the browser and transferred to a Web Worker running on the same device. The merged workbook is generated locally and downloaded from an in-browser object URL.

How a technical user can verify local processing
  1. Open your browser's Developer Tools and choose the Network tab.
  2. Load MergeStudio, add small test spreadsheets and run a normal merge.
  3. You can inspect the requests yourself: the local merge flow does not POST spreadsheet file payloads to a MergeStudio backend.

This is a verification tip, not a promise that the website makes no network requests at all: normal page assets, analytics and configured error diagnostics can use the network as described below.

Spreadsheet files

Before local parsing starts, MergeStudio checks selected file sizes and estimates whether the job is safe for the browser. Local jobs are transferred to a background worker within your browser and remain on your device.

Very large jobs

The cloud-processing backend is not connected. If MergeStudio determines that a job is too large for safe local processing, it stops before parsing and tells you that cloud processing would be required. The current production tool does not upload that oversized job anywhere.

If temporary cloud processing is enabled in the future, the tool will identify that mode before upload and this policy will be updated to describe storage, retention and deletion behavior.

Downloads

For local jobs, the merged workbook is generated inside the browser and downloaded from an in-browser object URL. The result does not need to be stored on a MergeStudio server.

PDF files

The Merge PDF and Split PDF tools read, preview, merge and split PDFs entirely inside your browser using a Web Worker on your device. They have no upload path: PDF contents are never sent to MergeStudio or anyone else, and the resulting PDFs (or ZIP file) are downloaded from in-browser object URLs. If you enter a password to open a protected PDF, it is used only in the browser to open that file and is not stored or transmitted. PDF analytics are limited to fixed step events (file added, merge or split started, file downloaded) and never include file names, sizes, page counts, page ranges, passwords or contents.

Hosting

The public website can be served as static files from Vercel. Like most web hosts, Vercel may process ordinary request metadata needed to deliver the site, such as IP address, user agent, requested URL and timing information. This is separate from spreadsheet contents selected inside the tool.

Website analytics

We use Google Analytics to understand website traffic, including public pages visited, device information and referral sources. After a successful download, MergeStudio may also record fixed anonymous feedback events such as whether the feedback prompt was shown, whether the user chose “Worked great” or “Needs work,” and a selected issue category. We do not collect free-text feedback in this flow, and we do not send spreadsheet contents, source filenames, sheet names or matching-column values as analytics events. Analytics is separate from local spreadsheet processing.

Error diagnostics

When MergeStudio itself fails — for example a worker crash or unexpected merge failure — we may send a limited technical report so the fault can be found and fixed. Spreadsheet contents are not included in these reports.

A report can contain only a fixed error code from an allowlist, fault stage, app version, public route, browser family, operating-system family, device class, a random reference number and a sanitized code stack with our own file and line information.

A report never contains file names, sheet names, column names, the columns you matched on, cell values, spreadsheet contents or the files themselves. Anything our code cannot classify against the allowlist is discarded rather than sent. Expected outcomes such as unsupported files, jobs over documented limits, an invalid header row or no matching rows are not treated as software defects.

Where reporting is enabled, reports are processed by Sentry (Functional Software, Inc.) acting as a processor. If no error-monitoring provider is configured, no error report is transmitted.

Third-party assets

The site may load external web assets such as Google Fonts. Those providers can receive normal web request metadata when those assets load. Spreadsheet contents are not intentionally included in those requests.

Practical limits and safeguards

Browser memory varies by device. MergeStudio therefore uses conservative checks for raw file size, estimated working memory, worksheet size and result growth. A job can be stopped even when a powerful computer might technically complete it; this is intentional to reduce the risk of a frozen browser tab.

Accounts and retention