A comma is not always a separator
Consider the CSV line 001,"Doe, Jane",Active. The comma inside the quoted name is part of one field. A parser that simply splits on every comma turns a three-column record into four columns. That's a broken import, even though the file looks straightforward at a glance.
CSV can also include line breaks inside quoted fields and doubled quotes for a literal quote character. RFC 4180 documents these common conventions. A useful converter needs to handle them rather than treating every new line as the start of a new record.
Text that looks like a number may not be one
SKUs, postal codes, order references and IDs may start with zeros. Turning the string "00123" into the number 123 changes its identity. The same problem appears when a spreadsheet turns a long reference into scientific notation or guesses a date format.
RezSat's CSV to JSON Converter keeps values as strings. You can convert fields to numbers in your application later, deliberately and with validation. It is easier to add types correctly than to recover digits that have already been discarded.
Headers make JSON objects more convenient
With headers enabled, a first row like id,name,city becomes keys on each JSON object. The next row becomes {"id":"001","name":"Asha","city":"Kandy"}. Without headers, the converter returns arrays of arrays instead.
Duplicate column names are dangerous because object keys must be unique for an unambiguous mapping. This converter rejects duplicate or empty headings instead of silently overwriting one value with another.
CSV isn't one perfectly standardized dialect
Some applications use semicolons because commas are used for decimal notation. Others export tabs. The converter supports comma, semicolon and tab as selectable separators. It also validates the number of columns in each record and reports malformed quotes.
That validation is a feature, not a nuisance. A mismatch might indicate damaged input or the wrong delimiter. Fixing the source is better than generating plausible-looking but incorrect JSON.
When a browser converter is not the right tool
For a small configuration file, export or list, a browser conversion is quick and convenient. For millions of records or regulated customer data, use a tested batch import process with schema checks, logs and an explicit data handling agreement.
RezSat keeps the conversion local and caps input to protect your browser. It does not upload your CSV. Always keep a backup of the original and inspect a few known rows before using the output in production.
Useful links and sources
These links point to the original tool or official documentation. Features and free-tier limits may change.
- RFC 4180 — CSV format — Quoted fields, commas and embedded newline conventions
- MDN — JSON — How JSON serialization works