json → csv
Turn JSON into a spreadsheet-ready CSV, with headers detected automatically.
Most tools that read JSON want CSV, and most spreadsheet tools want CSV. This converter does the translation instantly in your browser, with a live editor so you can paste JSON on the left and copy clean CSV on the right. The header row is built from the union of every key in your data, so records with differing fields are handled without silently dropping columns.
100% client-side — your files never leave your device
Conversion runs locally in your browser using Canvas and WebAssembly. There is no upload step, no server processing and no file storage. Disconnect from the internet and this page still works.
Step by step
Drag and drop your file into the box above, or click it to browse your device. Add several at once and they convert together as a batch.
Everything is configured automatically — the default settings produce an optimal .csv for almost every use.
Click Download to save the result straight to your device. The whole process took a fraction of a second because nothing was uploaded or downloaded.
Side by side
Here is how the two formats differ. Use it to decide whether converting is worth it, and which one to pick if you have a choice.
| Attribute | JSON.json | CSV.csv |
|---|---|---|
| Full name | JSON (JavaScript Object Notation) | CSV (Comma-Separated Values) |
| Compression | Text-based | Text-based |
| Transparency | No | No |
| Browser support | Universal | Universal |
| File size | Text | Text |
| Best for | APIs, configs and web apps | Excel, Sheets and databases |
The guide
Three common shapes are handled. An array of flat objects — by far the most common API response — becomes one CSV row per object. An array of arrays becomes a grid where the first row is used as the header when it contains no repeated values, otherwise generic column names are generated. A single top-level object is treated as a one-row table, which is convenient for small config exports.
CSV has no concept of nesting, so an object or array value is serialised as compact JSON inside its cell, with quotes doubled per the CSV specification. So `{"user": {"name": "Ada", "id": 7}}` produces the cell `"{""name"":""Ada"",""id"":7}"`. This is lossless — you can parse the cell back into a nested object — but if you want separate columns, flatten the JSON before converting, or build the nested shape after the round trip.
The header row is the union of all keys in the array, in the order they are first encountered. That guarantees no data is lost when some records have extra fields, but it means column order reflects the first occurrence of each key rather than alphabetical order. If you need a fixed schema, make sure the first record contains every key you intend to use.
Common questions
Everything about how this converter handles your files, and how to get the best result.