Frequently asked questions

Short answers about the tools, browser-local files, limits, privacy and planned advertising. For step-by-step import problems, use the how-to guides.

What is TableMender?

TableMender is a small set of free browser tools for CSV and Excel handoffs: convert CSV to a text-preserving workbook, clean duplicates or empty records with explicit rules, and check delimiters, quoting and encoding before you import elsewhere. It is an independent project, not affiliated with Microsoft, Google or any exporting application.

Do my files leave this browser?

No. The tools read the file or pasted text you provide in browser memory, show a preview and generate a download on your device. There is no account, no file-upload API and no saved file history. Ordinary page loads still use Cloudflare hosting, so connection information such as IP addresses and requested URLs can be processed under hosting and security policies. Tool file contents are not sent by the Cloudflare Web Analytics beacon either. See the privacy policy.

Which tools are available?

Three tasks share one workbench:

• CSV to Excel — download an XLSX workbook that keeps fields as text by default so product codes, postal codes and long IDs stay intact. You can explicitly choose Number for quantity columns when you need arithmetic.
• CSV clean — remove duplicates or empty records, optionally trim edge whitespace, review change counts and restore the original preview before export.
• CSV check & repair — inspect separators, encoding and structural errors with record and line locations, then export UTF-8 CSV with explicit settings.

All three can export CSV or Excel without re-importing the result. Keep an original copy and compare important identifiers before you trust a download.

What are the file limits?

Current limits are 5 MiB input, 20,000 records including the header, 256 columns, 250,000 cells and 32,767 characters per field. Delimiters supported for input are comma, semicolon, tab and pipe. Browser memory and device speed still vary; a file that fits the published limits can still be slow on a constrained device. Details also appear on the terms page.

Can TableMender restore zeros or characters that are already gone?

No. If an earlier export already dropped leading zeros, shortened a long ID into scientific notation, or saved mojibake as literal characters, another pass here cannot invent the missing digits or restore the original bytes. Start from the original system export whenever possible. The guides explain how to recognize those injuries before you overwrite your only good copy. When zeros or long IDs are already gone, prefer a re-export over another local pass—see Repair versus re-export.

Can I open an existing Excel workbook?

Not in this release. The tools accept CSV or plain text. They export XLSX or UTF-8 CSV. They do not import .xlsx/.xls workbooks, run spreadsheet formulas or recover a damaged workbook. If your source is already a workbook, export CSV from it carefully or use your spreadsheet’s text import tools for identifier columns.

Do I need an account, and is it free?

No account is required. The current tools are free to use. There is no paid conversion service in this release. Funding plans are described below; they do not change the browser-local processing model for your file contents.

Are you showing Google ads today?

Not in this release. TableMender plans to show Google AdSense advertisements later. The site does not load an AdSense tag or Google Analytics now, and it does not claim AdSense approval. Cloudflare Web Analytics is enabled for aggregate page views and performance; that beacon is not AdSense and is not used to serve ads. Before ads appear for visitors in the EEA, the UK or Switzerland, Google’s certified consent platform (Funding Choices / Privacy & messaging) will be enabled. Until then, the footer link “Privacy choices” opens the advertising section of the privacy policy. More detail is on the cookies & storage page.

Does TableMender set cookies or store my preview?

The application does not set cookies and does not write tool contents, identifiers or consent records to cookies, localStorage, sessionStorage or IndexedDB. Cloudflare may still apply technical security cookies when a security feature requires them. Planned AdSense cookies are described on the cookies page and will not load until advertising and the consent platform are turned on deliberately.

Why do the tools need JavaScript?

Parsing, preview and export run entirely in your browser. Without JavaScript those steps cannot run. The how-to guides, privacy text and this FAQ remain readable with scripting disabled. Keep a source copy of any file you care about, regardless of which tool you use.

When should I use a how-to guide instead of a tool?

Open a tool when you already know the task: convert, clean or check a file. Open a how-to guide when you need to recognize a failure mode first—leading zeros, one-column opens, date-looking text, scientific notation, encoding, quotes, duplicates, empty rows, merge preflight, repair versus re-export or Excel Save As CSV pitfalls. Guides include original teaching examples and downloadable sample CSVs; they do not process your private files.

How can I prove my CSV is not uploaded?

Open your browser’s Network panel, enable Preserve log, clear the list, then preview and download a synthetic file in CSV to Excel. You should not see a POST whose body contains your rows. Ordinary requests for scripts, styles and optional Cloudflare Web Analytics beacons are hosting or measurement traffic—not a conversion upload. A short walkthrough is in How to prove TableMender does not upload your CSV.

What does the local preflight summary check?

After you press Preview, each tool shows a heuristic summary of the parsed source (not the cleaned export): encoding/BOM hints, delimiter certainty, fully blank data rows, whole-row duplicate risk, identifier risks (leading zeros, 16+ digit tokens, exponent-looking values, ZIP+4 shapes, plus-prefixed phones), blank or repeated headers, date-looking text, formula-like fields, edge whitespace and replacement characters (�). A tally counts warnings, notes and clear checks, and warnings are listed first. Each row includes a What to do step. When a check fires, it can link to the matching how-to on this site. You can download that summary as a UTF-8 CSV in checklist order, which is not the on-screen order. It does not change your file, is not a guarantee that Excel will agree, and never leaves the browser.

Why is download blocked after preview?

The download button stays disabled when the input delimiter is still uncertain, nonempty records have different field counts, the chosen export scope has zero data rows, or a column you marked as Number is not a plain decimal (leading zeros, plus signs, hyphens, commas, exponents or more than 15 significant digits). The status line under the button names the next step. Blank physical rows do not block download; they are padded to the header width unless you remove them. Quoting errors stop the parse before a preview exists — fix the named record, line and field first.

What filename will my download use?

Downloads keep your original name when you chose a file, then add a suffix so they do not replace the source: -converted on CSV to Excel, -repaired on CSV check & repair, -cleaned on CSV clean, plus -matched when you export only filter matches. The preflight summary downloads as -preflight.csv. Duplicate review (Clean only) downloads as -duplicate-review.csv and is not the cleaned data file. Clearing the tool does not delete files already saved on your device.

How do I load a teaching sample without uploading?

On each tool page, choose a problem CSV from the sample pack and press Load sample. The same teaching bytes as /samples/ are already in the page — nothing is fetched or uploaded. Then press Preview. Samples cover leading zeros, semicolon/one-column files, mojibake, ZIP+4, long digit IDs and quoted line breaks. Guides also link the matching downloadable CSV.

How do I report a problem or ask a privacy question?

Email contact@tablemender.app through the contact page. Include the page, browser, a small synthetic example and what you expected versus what you saw. Do not send confidential customer records. Contact mail is handled separately from browser-local file processing.

What keyboard shortcuts do the tools support?

On a tool page, Ctrl+Enter or Command+Enter runs Preview from the workbench (including from the paste box). Escape moves focus to the error banner when one is shown, and also closes the mobile menu or first-visit walkthrough. Tab moves through native controls. The preview table region scrolls with arrow keys once it is focused. Undo last change restores the previous file, paste, sample or clear. On CSV clean, Restore original preview turns cleaning rules off without deleting your paste. Details are on the accessibility page.

Who maintains TableMender, and how are changes tested?

One operator of the Luminesca project maintains the site, tools and guides. Guides disclose AI-assisted drafting. Parser, clean, export and publication checks run in the repository before a release. Those are software checks, not a human peer review or a WCAG certification. Dated product changes are listed on the About changelog. The editorial policy states that we do not invent testimonials, user counts or AdSense approval.

Can I compare the original parse with the cleaned result?

Yes. After Preview, use Original parse and Result above the table. Changed cells are highlighted on the result view (for example a trimmed field). Download always exports the result, not the original-parse view. This is most useful on CSV clean; the same toggle exists on the other tools when the result differs, such as after removing blank rows.

Last updated: October 31, 2026.