Paste CSV, or open a file exported from a spreadsheet, and get a JSON array with one object per row. Commas, semicolons, tabs and quoted cells are all understood.
Runs entirely in your browser — nothing you enter here is sent to a server.
CSV is the lowest common denominator of data exchange: every spreadsheet, database and reporting tool can export it. JSON is what APIs and application code expect. The conversion takes the header row as the list of keys and turns every following row into an object, so a table of 500 customers becomes an array of 500 objects with the same fields.
What makes CSV tricky is that it was never strictly standardised. The same "CSV" may use commas or semicolons, wrap text in quotes or not, and hide line breaks inside a cell. The converter follows RFC 4180 and copes with the usual variations.
The first line is checked for commas, semicolons, tabs and pipes. Excel in many European locales exports semicolons, because the comma is the decimal separator there.
A cell in double quotes may contain the delimiter, line breaks and quotes (written twice: ""). All three are read correctly.
With detection on, 25 becomes a number, true a boolean and an empty cell null. Values with leading zeros, such as zip codes, stay strings.
Untick "first row is the header" and the keys become column1, column2 and so on.
Most failed imports come down to a handful of causes. A file saved from Excel may start with an invisible byte-order mark, which ends up glued to the first column name — it is removed here. Duplicate column names would overwrite each other in an object, so later ones get a numeric suffix. And numbers formatted for people — 1,250.00 or 1 250,00 — are not numbers to a parser; export them unformatted, or keep them as strings and clean them in code.
In Excel choose Save As and pick CSV (comma delimited), then open that file here. Each sheet has to be exported separately, since CSV holds a single table.
The file uses a different delimiter from the one assumed. Leave the delimiter on automatic detection, or select semicolon or tab explicitly.
To null when type detection is on, and to an empty string when it is off.
The file is processed in your browser's memory, so tens of megabytes work on an ordinary computer. Nothing is uploaded.
Upzilla checks your sites, servers and APIs around the clock and alerts you the moment something breaks. 10 monitors free, no card required.