JSON to CSV Converter - Arrays of Objects to Spreadsheet Rows

Default array of objects

[
  { "a": 1, "b": 2 },
  { "a": 3, "b": 4 }
]

CSV output:

a,b
1,2
3,4

Nested object - flatten on

[
  { "user": { "id": 1 }, "ok": true }
]

Flatten emits a user.id column plus ok. Stringify instead puts {"id":1} in the user cell and leaves ok as a boolean. Duplicate logical columns after flattening (a nested path and a literal dotted key) last-write-wins in the flattened map.

Opening an API list in a spreadsheet

REST endpoints often return an array of objects. Pasting that array here produces a header row and one spreadsheet row per object. Analysts can then filter, pivot, and chart without writing a Python one-liner. Flatten nested user or address objects when those should become columns.

Preparing a database import

Many warehouses and admin UIs import CSV, not JSON. Converting an array of records locally avoids uploading the JSON to a third-party converter. Empty cells for missing keys match how CSV imports usually treat optional columns.

Comparing two exports in Excel

JSON diffs are trees. Spreadsheet diffs are tables. If both dumps are arrays of objects with stable keys, CSV is the format that Excel and Google Sheets already know how to highlight. Flatten first so nested ids become columns you can VLOOKUP.

Keeping nested blobs in one cell

Sometimes a nested object is not a set of columns - it is a payload you want to preserve. Turn flatten off. Papa puts JSON.stringify of that object in one field. Arrays as cell values stringify the same way. That is stringify mode, not flatten mode.

Cleaning rows in the JSON editor first

If objects are messy, edit them in table mode on the JSON editor, then paste the array here. This converter does not rename keys or drop columns; it only unparses what you give it.

Documenting a sample table in a ticket

A two-row default is already a complete CSV example. Replace a and b with the keys your API actually uses, copy the CSV, and paste it into a GitHub issue. Reviewers who do not read JSON still see a table.

Handling sparse objects

Row one may have keys a and b; row two may add c. Headers are the union. Missing cells stay empty. That is how CSV represents optional fields. You do not need to pad objects with null first unless you want the word null in a cell - this page treats JSON null as an empty field.

Avoiding a huge-file textarea

If the array is a 20 MB dump, do not paste it here. Use the JSON file processor to inspect or minify, then convert a sample, or run Papa in a local script. This page is for documents you are willing to keep as a string in the browser.

What JSON shape converts to CSV?

A JSON array of objects. The default [{"a":1,"b":2},{"a":3,"b":4}] becomes the header a,b and two data rows. A single object is wrapped as one row so you are not stranded, but a nested config tree is still a tree, not a table.

How are nested objects handled?

Flatten mode turns {"user":{"id":1}} into a user.id column. Stringify mode puts {"id":1} in one cell as JSON text. Arrays as cell values stringify. Choose flatten when you want spreadsheet columns; choose stringify when nested structure should stay in one field.

Is this the reverse of CSV to JSON?

Yes, in spirit. CSV to JSON already exists on this site. JSON to CSV is the opposite direction and will not silently rebuild comments, original quoting quirks, or a column order that never existed as object key order in JSON.

Does conversion upload the data?

No. Papa Parse unparse runs in the browser. Drafts stay locally for up to 30 days. Nothing is posted to a server. Clear restores the default two-row array.

What about duplicate headers?

Object keys are unique in JSON after parse. Flattening can still collide if one row has both user.id as a nested path and a literal "user.id" key; later values win in the flattened map. That is a last-write-wins map, not a CSV error.

Can I convert a huge file?

Use a modest array in this textarea. Very large tables belong in the JSON file processor or a local script. A 50 MB array of objects will struggle in a textarea even if Papa could theoretically unparse it.

What happens to null, booleans, and arrays?

Booleans and numbers stay unquoted unless Papa decides they need quotes. Null becomes an empty field. Arrays as cell values stringify to JSON text. Missing keys across the union of columns become empty cells.

Does column order follow the first object only?

Headers are the union of keys after flatten or stringify, in the order Papa sees them from the prepared rows. A key that appears only on the second row still becomes a column. Missing cells on other rows stay empty.

Can I convert a single JSON object?

Yes. A single object is wrapped as one row. That is a convenience, not a claim that every JSON document is a table. Deeply nested configs still need flatten or stringify, and arrays of primitives are not objects.

Is this JSON to CSV converter free?

Yes. No signup, no row cap beyond what your browser will hold, and no upload. Convert as many arrays as you need, then copy the CSV into a spreadsheet or a database import.