Flatten Nested JSON. One level deep.
Collapse deeply nested JSON into flat, single-level keys using dot or bracket notation — then export it as CSV.
Your flattened result will appear hereHow to use Flatten Nested JSON
Paste your nested JSON
Any depth of nesting is fine — API responses with objects inside arrays inside objects are the normal case here.
Pick your key notation
Choose dot notation (user.address.city), bracket notation (user[address][city]) or a custom separator, and decide whether arrays are indexed or kept as JSON.
Copy the flat JSON or export CSV
Take the flattened object as JSON for a config or query layer, or switch to CSV output for a spreadsheet.
Why use Parsefy Flatten Nested JSON?
Your data never leaves your device
Everything runs in your browser tab — there is no upload step and no server to store anything. That makes it safe for API responses, database dumps and production data you could not paste into a hosted converter.
Handles arbitrarily deep nesting
Objects inside arrays inside objects are collapsed in one pass, so you do not have to write a recursive helper just to inspect an unfamiliar payload.
Notation that matches your tooling
Dot notation suits spreadsheets and MongoDB queries, bracket notation matches form field names and PHP-style query strings, and a custom separator covers everything else.
No sign-up, no file-size tier
There is no account, no email wall and no paid plan gating bigger files. The only real limit is how much memory your own browser can spare.
Flatten Nested JSON — frequently asked questions
What does flattening actually do?
It rewrites a nested structure as a single-level object where each key is the full path to a value. {"user":{"address":{"city":"Berlin"}}} becomes {"user.address.city":"Berlin"}. That is what makes nested data expressible as CSV columns, since a spreadsheet has no concept of a nested cell.
What is the difference between dot and bracket notation?
They encode the same path differently. Dot notation (user.address.city) is compact and matches how spreadsheets and MongoDB queries address fields. Bracket notation (user[address][city]) matches HTML form field names and PHP-style query strings, and is safer when your keys themselves contain dots.
How are arrays inside objects handled?
With array indexing enabled, each element gets its own numbered key, so tags becomes tags.0, tags.1 and so on. With it disabled, the array is kept as a compact JSON string in a single key — better when arrays vary in length and you do not want a ragged, ever-widening set of columns.
Can I flatten JSON without converting it to CSV?
Yes. The flattened JSON output is a first-class result you can copy on its own — useful for building dot-path query filters, comparing two payload shapes, or feeding a system that expects flat key-value config.
Is my payload sent anywhere?
No. Flattening is pure JavaScript running in your browser, so nested production payloads and API responses stay entirely on your device.