Json to Csv

APIs and apps hand you JSON, but people want spreadsheets. Paste JSON here — an array of records, a single object or nested data — and this converter flattens it into rows and columns, gathers every field into the header, quotes values correctly, and gives you a CSV ready for Excel, Google Sheets or a database import. Nothing is uploaded: the conversion runs on your device.

How the conversion works

1. The converter finds the records: a top-level array, or the first array of objects inside an object (such as {"data": [...]}); a single object becomes one row.
2. Each record is flattened: nested objects become columns joined with dots, so {"address": {"city": "London"}} becomes a column address.city.
3. Every field that appears in any record becomes a column, in the order first seen; missing values are left blank.
4. Values containing the delimiter, quotes or line breaks are wrapped in double quotes, and quotes inside are doubled, following the common CSV standard (RFC 4180).
5. The result can be previewed, copied or downloaded.

Worked example

The sample JSON on this page produces this CSV. Grace’s name contains a comma, so it is quoted; Linus’s name contains quotation marks, which are doubled inside quotes. Fields that only appear in some records — zip and active — still get a column.

Arrays: three ways to handle them

Arrays of objects (for example a list of order items) are kept as JSON text in join mode, because a single cell can’t hold a table; use spread mode to turn them into numbered columns such as items.0.sku.

Opening the CSV in Excel

• Keep “Add UTF-8 BOM” on so Excel shows accented letters and symbols correctly.
• If your Excel uses a comma as the decimal separator (common in Europe), choose the semicolon delimiter so columns split properly.
• Long numbers such as IDs or phone numbers may be shown in scientific notation or lose leading zeros; import the column as Text using Data → From Text/CSV.
• Google Sheets: File → Import → Upload, and choose “Detect automatically” for the separator.

Fixing invalid JSON

When JSON can’t be parsed, the converter shows the error and, where the browser reports it, the line and column so you can find the problem quickly.

JSON and CSV compared

Because CSV has no types, numbers, dates and true/false values all become plain text. Spreadsheets guess the type when they open the file, which is usually helpful but can change IDs with leading zeros or long digit strings — import those columns as text.

Common JSON shapes and how they convert

• Array of objects — [{...}, {...}] — each object becomes a row. This is the most common API format.
• Wrapped array — {"data": [{...}]} or {"results": [...]} — the converter finds the first array of objects and uses it.
• Single object — {...} — becomes one row with a column for every field.
• Array of values — [1, 2, 3] — becomes a single “value” column.
• Deeply nested data — flatten mode creates long column names such as order.customer.address.city; switch nested objects to “Keep as JSON text” if you prefer fewer columns.

Using the CSV in a database or another tool

Most databases and data tools import CSV with a header row. Match the delimiter and encoding in the import settings (UTF-8, comma or semicolon), and decide how empty cells should be treated — as empty strings or as NULL. If the target system expects particular column names, rename them in a spreadsheet first, or use the mapping sheet from the templates pack.

Privacy and large files

The file is read and converted entirely in your browser; nothing is sent to a server. Files of several megabytes convert in a moment on a modern computer. For very large files (hundreds of megabytes), a command-line tool or a database import is more suitable.

Data templates pack

The optional pack includes an Excel data dictionary template for documenting columns, an import mapping sheet for matching CSV columns to a target system, a data-cleaning checklist and a CSV import log. The converter above is free to use.

AI-assisted content

This page was drafted with AI assistance and reviewed by Kedop.