Developer · THE NO-PANIC PLAN
Convert a CSV delimiter without breaking quoted fields
Changing the delimiter in a CSV is a data transformation, not a find-and-replace. A comma or tab inside a quoted value must remain part of that value while the field separator changes, and different applications interpret CSV dialects differently. This workflow uses Nirmion's CSV Delimiter Converter (tool 143) for bounded comma, semicolon, tab, or pipe conversions, then checks the output in the receiving application. The converter changes delimiters only; it does not change encoding, dates, decimal conventions, data types, or spreadsheet formula safety.
MISSION Convert a bounded CSV file to a recipient-required delimiter while preserving rows and field values, then verify the result in the actual import application and review spreadsheet formula risks.
Convert and verify a CSV for its receiving applicationTHE REAL-WORLD BIT
What happens outside this browser tab?
Ask the recipient which delimiter and import settings it expects; inspect the source dialect and preserve a backup; convert only a bounded, non-sensitive copy with the named delimiter tool; validate records and quoted fields with a parser and destination preview; separately assess spreadsheet formula injection if a person will open the output; then deliver the verified file with its delimiter, encoding, and version documented.
YOUR CHECKLIST, WITH FEWER DRAMATIC SIGHES
One step at a time.
Follow the order below. If a step names a Nirmion tool, its link is right there with it.
- 01
Confirm the recipient's exact CSV expectations
Ask the receiving database, importer, spreadsheet, or partner which delimiter it accepts: comma, semicolon, tab, or pipe. Confirm whether it expects a header row, text qualifier, character encoding, line endings, decimal convention, and a particular extension such as `.csv` or `.tsv`. Do not infer the required separator from a user's region or from the filename alone; spreadsheet import settings can override automatic detection. Record the source and destination requirements, expected columns, and approximate row count. If the recipient requires a different schema, date format, encoding, or data type, a delimiter change alone will not satisfy that requirement; plan a separate transformation with an appropriate parser. (Sources 1, 3)
- 02
Inspect the source dialect and preserve the original
Keep an untouched copy and inspect a small, authorized sample in a text editor or parser. Identify the actual field separator, quote character, escape convention, header presence, encoding, and line endings. RFC 4180 documents common comma-separated behavior: fields may be quoted, commas and line breaks inside fields need quoting, and a quote inside a quoted field is represented by two quotes. The RFC is informational and implementations vary, so verify the sender's dialect and the destination parser instead of assuming every CSV follows it. Check that a sample record with a quoted separator, an embedded quote, an empty value, and a header is represented as expected before converting. (Sources 1, 2)
- 03
Convert a non-sensitive copy with the named delimiters
For a bounded file that is appropriate to process in a browser utility, open Nirmion's CSV Delimiter Converter (tool 143), choose the source and required target delimiter, and convert a copy rather than the only source. The tool supports comma, semicolon, tab, and pipe. Check the preview around quoted fields before accepting the result; a comma inside a quoted address or description is data, not a separator to replace blindly. The published tool uses client-side processing, but do not paste credentials, private customer records, or other data you are not authorized to process. If the file exceeds the tool's supported input size or contains confidential data, use an approved local parser instead. Save the result as a new file and record the chosen target delimiter. (Sources 2, 3)
- 04
Validate rows, columns, quotes, and values
Compare the source and output record counts, header names, and field counts; inspect rows that contain the target delimiter, quotes, embedded newlines, leading or trailing spaces, and empty cells. Use a parser that supports explicit dialect settings, such as Python's `csv` reader and writer, or import through the receiving application's data-import preview. Check that text values remain text and that long identifiers, leading zeros, date strings, and decimal values have not been reinterpreted. In Excel, use Get & Transform Data > From Text/CSV and explicitly select the delimiter, then review the preview before loading. A successful delimiter conversion does not prove that the recipient accepted the encoding or schema. (Sources 2, 3, 4)
- 05
Check spreadsheet formula risk separately
If a person will open the converted file in spreadsheet software, check for untrusted cells that begin with formula-triggering characters such as `=`, `+`, `-`, `@`, tab, carriage return, or line feed. Quoting a cell or changing its delimiter is not a universal formula-injection defense; OWASP notes that spreadsheet behavior can change after a save-and-reopen cycle and that separator and quote characters can affect cell boundaries. Decide on a mitigation for the actual consumer and data use, then test with synthetic values in a safe spreadsheet copy. Do not silently alter values intended for a machine import, and do not describe the delimiter converter as a sanitizer or security filter. (Source 4)
Evidence:OWASP: CSV Injection - 06
Deliver the tested file with its format documented
Save the verified output under a new, clear filename and use an extension that matches the recipient's documented import path; changing `.csv` to `.tsv` does not itself change the file contents. Record the chosen delimiter, header setting, encoding, line ending if relevant, receiving parser or spreadsheet version, record count, and review date. If possible, have the receiver import a test copy and confirm the expected fields before replacing a live dataset. Retain the source file and conversion notes until the receiver approves the result. If parsing differs, stop and compare dialect settings rather than repeatedly converting the converted output, which can compound quoting and data-loss errors. (Sources 1, 3, 4)
THE HELPER CREW
Tools for the fiddly bits.
These are the currently published Nirmion tools matched to this guide. Open a tool page for its accepted inputs and limits.
RECEIPTS, PLEASE
Sources & review notes
Each source is linked to the steps it supports. Open it to check its scope and current guidance.
Source checked 2026-10-10