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DataTray

Free for Windows 10 & 11

For the data files that break Excel

Open the CSV that stopped at a million rows, the workbook that will not load, the Parquet file Windows has never heard of. Find the duplicates, fix the formats, see what changed — and get a report you can send. Nothing uploads.

See it in action
  • No upload, ever
  • No row limit
  • No account

See it in action

This is the whole app

Five tiles in a tray window. Click through it here before you install anything.

9:41

Five tools

One tray, five things to do to a file

Organised by what each one does to your data — from the tile that changes nothing at all to the one that rewrites every value you tell it to.

Data Explorer

Read-only, always. Open a CSV, Excel workbook, Parquet directory or JSON file of any size and look at the rows — then switch to Columns for a full data profile: what every column actually holds, where the nulls and the mixed types and the outliers are, a data-quality read on each one, and a data dictionary you can hand to someone. A third tab takes SQL if you want it, and never asks you to write any if you don’t. Nothing here modifies the file; the only things written are the exports and reports you ask for.

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Data Converter

CSV, TSV, Excel, Parquet, JSON, JSONL and XML, in whichever direction you need — including the ones Windows has no answer for. Twelve files into one, or one file split into twelve, because converting, combining and splitting are the same job at different cardinalities. Drop a folder in and it works out which you meant.

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Dedupe & Merge

Excel tells you “482 duplicates removed” and nothing else — you cannot see what left, get it back, or show anyone what happened. Every dedupe here ends in a removals report: every dropped row, the row it lost to, and why. Match exactly, or normalized so “Acme Corp.” and “ACME Corp” stop being two customers, or fuzzy when the spelling is genuinely different — then coalesce the survivors so the fullest record wins rather than the first one.

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Clean & Anonymize

Trailing whitespace, dates in four formats, numbers stored as text, the leading zeros that vanished, encoding that turned é into é. DataTray finds them without being asked and fixes them in one previewable stack of operations — and in the same pass it finds the personal data, so you can mask, hash or tokenize it before the file goes anywhere. Every finding is a deterministic rule over the column, explainable in one sentence. No model, no API key, nothing uploaded.

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Compare Files

Point it at two files, two sheets or two Parquet directories. It reports the schema drift first — columns added, removed, retyped — then diffs the rows themselves, cell by cell where you have a key column. Numeric and date tolerances mean float noise and timestamp granularity do not read as changes. Out comes a report you can send and an .xlsx with a sheet per category, which is the form people actually circulate.

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Why DataTray

Every other free way to do this asks you to upload the file first

That is the whole argument. A spreadsheet of customers, salaries or patient records is not something to hand to a website you found on the first page of results.

It opens

Size is not a category here. A multi-gigabyte CSV, a forty-sheet workbook, a folder of Parquet files — DataTray reads them where they lie instead of loading them into memory, and shows you the first rows while it works.

Nothing leaves

No upload, no API key, no model download, no cloud step you did not ask for. Not one of the five tools makes a network request — which is what makes this a promise rather than a policy.

You get something to send

Every job ends in an artefact: a self-contained HTML report you can email and an .xlsx your manager can open. Excel tells you “482 duplicates removed”; DataTray shows you which 482.

Transparent funding

How DataTray stays free

DataTray shares a slice of your device’s idle internet bandwidth, when it can, through Massive, our vetted partner — that’s what pays for development instead of a subscription, a row limit, or ads. It relays other people’s web traffic. It never reads, sends or touches your files.

  • Disclosed before anything runsSpelled out at install — you agree to it, or you don’t install.
  • Never your dataIt relays other parties’ traffic. Your spreadsheets are not part of it.
  • Off in one clickA toggle in Settings, one click from the tray menu — not buried.

Two separate things, and neither one touches your data: DataTray never uploads your files, and it is free because it shares a small amount of your computer’s unused internet bandwidth.

Read the full explanation
  • Nothing uploadsEvery byte stays on the machine. There is no server on the other end to send it to.
  • No account, no keyNo sign-up, no credits, no seat, and no trial that stops working on a Tuesday.
  • Nothing fetched laterNo AI models, no database engine to install, no extensions downloaded the first time you open a spreadsheet.

How it works

Three steps, and the file never moves

DataTray lives in the system tray. It is there when a file lands, and out of the way when one does not.

  1. 1

    Install it

    One installer, then a green icon in the tray. Nothing downloads afterwards and nothing asks you to make an account.

  2. 2

    Drop the file in

    DataTray works out the delimiter, the encoding and the column types on its own — including the semicolon file that opens as one column in Excel — and shows you the rows.

  3. 3

    Take the result and the report

    Your original is never modified. Out comes a new file beside it, plus a report of exactly what was found, changed or removed.

Get DataTray

Open the file that would not open

Free, ad-free, and it never asks for the file.

Windows 10 & 11

No account, no card, no upload.

Questions

The things people ask first

Short answers. The longer ones are in the docs.

Free, with no paid tier waiting behind it. DataTray is funded by sharing a small amount of your computer’s idle, unused internet bandwidth through Massive, our vetted partner — which is a separate thing from your files and never touches them. You are told at install time, and you can turn it off in Settings. The full explanation is on how it’s funded.