✳ OMNIVIEWER

Query your CSV with SQL.

safe · secure · no server · works offline · fast

…or just start typing at the cursor.

Or try it now

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Run SQL over a CSV — without uploading it or spinning up a database

Drop a .csv file and OmniViewer streams it into a real in-browser SQLite database, then lets you query it: write SELECT … FROM data with WHERE, GROUP BY, ORDER BY, joins and aggregates, and get a result table back. The whole file streams into the engine — nothing is uploaded and there is no server.

SQL is the fastest way to answer a real question about a dataset — a count, a top-N, a sum per category — without loading the file into a spreadsheet or writing a script. The same drop also shows the CSV as a table, converts it to JSON, reports per-column stats, and opens raw and hex views.

It’s one lens on OmniViewer’s CSV Viewer — Table, SQL & JSON, Locally: drop a file and every tab is one click away. OmniViewer opens every file format, entirely in your browser — no upload, no server.

FAQ

Is my CSV uploaded anywhere?

No. OmniViewer is a static page with no server-side processing: your CSV is read directly by your browser and never leaves your computer.

What is a CSV file?

CSV (comma-separated values) is a plain-text format for tabular data: one record per line, with fields separated by a delimiter — usually a comma, sometimes a tab or semicolon — and quoting for fields that contain the delimiter, a quote or a newline. It is loosely standardised by RFC 4180.

How large a CSV can I open?

Effectively unlimited. OmniViewer only reads the bytes needed to paint the screen, so the raw and hex views open a 20 GB CSV as readily as a 2 KB one; the engine behind them has been tested in-browser with a 40 GB file.

Can I see the CSV as a table, or query it with SQL?

Yes. OmniViewer shows a formatted, column-aligned table, converts the CSV to JSON, computes per-column statistics, and runs SQL against it with an in-browser SQLite engine (write SELECT … FROM data). The table, JSON and stats work on the first 32 MB of a very large file; the SQL engine streams the whole file. For the full file as a sortable, filterable table with column resizing and splitting across tens of gigabytes, use hugecsv.com (tested with a 21 GB, 100-million-row file).

How do I know what delimiter or encoding my CSV uses?

The hex view shows the exact bytes, so you can see whether fields are separated by commas, tabs or semicolons, whether lines end in CRLF or LF, and whether there is a byte-order mark. OmniViewer detects text vs binary from the content, not the extension.

How does this relate to hugecsv.com?

Same engine, same authors. OmniViewer is the universal front door for any file, with a CSV toolkit — table, SQL, JSON and stats — for everyday files. hugecsv.com is the specialised workbench for very large CSV files, with a WebAssembly parser, full-file sortable/filterable tables, column resizing and splitting across tens of gigabytes.