DevToolsmith

CSV Viewer

Open any CSV or TSV file as a clean table without Excel and without uploading it anywhere. Sort by clicking a column, filter rows as you type, and convert to JSON with one click.

Runs 100% in your browser — nothing is uploaded

6 rows × 7 columns · comma-separated
CSV
Tip: drop a file here424 chars · 424 bytes · 8 lines
#
11001Ada Lovelaceada@example.compro2026-01-0449.00true
21002Hopper, Gracegrace@example.comteam2026-02-11199.00true
31003Linus T.linus@example.comfree2026-02-280false
41004Margaret H.margaret@example.compro2026-03-1549.00true
51005Dennis "dmr" R.dennis@example.comteam2026-04-02199.00false
61006Barbara L.barbara@example.compro2026-05-1949.00true

Click a column header to sort.

Features

  • Auto-detects the delimiter: comma, semicolon, tab or pipe.
  • Handles real-world CSV: quoted fields with commas, escaped quotes (""), line breaks inside cells, and UTF-8 files with a byte order mark (BOM) from Excel.
  • Sort and filter: numeric-aware sorting (2 before 10) and instant search across all columns.
  • Repairs headers: empty header cells get names like column_3, and duplicates get a suffix.
  • Flags problems: rows with a different number of columns than the header are counted and reported.

What makes a valid CSV file?

CSV has no single standard, but RFC 4180 describes the common format:

  • Each record is on its own line. The first line can be a header.
  • Fields are separated by commas. Every row should have the same number of fields.
  • Fields containing commas, double quotes or line breaks must be wrapped in double quotes.
  • A double quote inside a quoted field is escaped by doubling it: "She said ""hi""".
Valid CSV with tricky fields
id,name,comment
1,"Smith, John","Said ""hello"""
2,Jane,"Line one
Line two"

Working with CSV on the command line

# Pretty-print a CSV as aligned columns
column -s, -t < data.csv | less -S

# Count rows (excluding the header)
tail -n +2 data.csv | wc -l

# Query CSV with SQL using DuckDB
duckdb -c "SELECT plan, count(*) FROM 'data.csv' GROUP BY plan"

Need the data as JSON for an API or a script? Use CSV to JSON.

To create markup from a JSON result, use JSON to HTML Table. A generated HTML table is useful for a small report; it does not retain spreadsheet formulas or provide a database for further queries.

Frequently asked questions

How do I open a CSV file online?

Drop the .csv file onto the input box above, or click Upload. It is read by your browser and shown as a table instantly. You can sort by any column and filter rows by typing in the search box. The file is never uploaded to a server.

Why does my CSV show everything in one column?

The file probably uses a different delimiter. Many European versions of Excel save CSV with semicolons, and exports from databases often use tabs. The viewer auto-detects the delimiter, but you can also pick it manually from the Delimiter menu.

Is there a file size limit?

There is no upload limit because nothing is uploaded. Files of several megabytes parse in a fraction of a second. The table shows the first 2,000 matching rows to keep scrolling fast, and the JSON view and filter work on the full data.

Can it open TSV files?

Yes. Tab-separated values are detected automatically, and you can also choose Tab in the Delimiter menu.

Why not just open the CSV in Excel?

Excel silently changes data when it opens a CSV: it strips leading zeros from IDs and zip codes, turns long numbers into scientific notation, and converts values like 1-2 or MARCH1 into dates. This viewer shows the raw text exactly as it is in the file.