JSON to CSV Converter
The JSON to CSV Converter takes a JSON array of objects (the most common API response shape) or a single JSON object and produces delimited CSV (Comma-Separated Values) output with automatic header detection from object keys. Useful for data analysts, marketers, and developers who pull JSON from REST APIs, MongoDB exports, or webhook payloads but need to load the data into Excel, Google Sheets, pandas DataFrames, or SQL tables that expect flat tabular CSV. The conversion handles several edge cases automatically: nested objects are flattened with dot notation (e.g., `address.city` becomes a column), nested arrays are joined with semicolons within a single cell, null/undefined values become empty cells, and inconsistent keys across objects produce a unified column set (missing keys yield blank cells). The default delimiter is comma, but you can switch to semicolon (preferred in European locales where commas serve as decimal separators) or tab (TSV, friendliest for spreadsheets that auto-detect column boundaries). CSV format itself is governed by RFC 4180: each record on its own line, fields separated by delimiter, fields containing the delimiter or newlines must be quoted with double quotes, and embedded quotes are escaped by doubling. The converter applies RFC 4180 quoting automatically so output opens cleanly in any spreadsheet program. UTF-8 encoding preserves international characters. Who this is for: Marketing analysts extracting Mailchimp or HubSpot data, developers debugging webhook payloads, data engineers prepping ETL pipelines, journalists analyzing scraped JSON, and anyone who has stared at a wall of JSON and wished it were a tidy spreadsheet. The tool runs entirely in your browser — no data leaves your device, so you can safely paste sensitive payloads.
CSV = HeaderRow + (each object → row of values joined by delimiter, RFC 4180 quoted)
- 1Step 1 — Paste your JSON into the input area (array of objects works best)
- 2Step 2 — Calculator validates JSON structure and surfaces parse errors with helpful hints
- 3Step 3 — Choose delimiter (comma is default; semicolon for European Excel; tab for TSV)
- 4Step 4 — Converter auto-detects unique keys across all objects to build column headers
- 5Step 5 — Each object becomes a row; missing keys produce empty cells; nested values flatten with dot notation
- 6Step 6 — Output appears in a copy-friendly text area with row and column count
- 7Step 7 — Copy to clipboard and paste into Excel, Google Sheets, or save as .csv file
Two keys (name, age) become headers; each object becomes a row.
Nested keys flatten with dot notation so the spreadsheet sees flat columns.
Union of all keys becomes column set; missing values are empty cells.
Arrays within objects join with semicolon inside one cell.
API data import to Excel/Google Sheets
Webhook payload debugging
MongoDB export prep for analysts
Marketing platform export (Mailchimp, HubSpot, Salesforce)
Quick data inspection before pandas/SQL load
Journalist data analysis on scraped content
What if my JSON contains commas inside string values?
The converter automatically applies RFC 4180 quoting — any field containing the delimiter, double quote, or newline gets wrapped in double quotes with internal quotes escaped. Output will parse correctly in any standards-compliant CSV reader.
How are nested arrays handled?
Nested arrays are joined with semicolons inside a single cell. For complex nesting (arrays of objects), the converter joins JSON-stringified subobjects so no data is lost. If you need deep flattening, normalize the JSON to one row per leaf record before converting.
Can I convert JSON Lines (NDJSON)?
Yes — paste the NDJSON wrapped in brackets to make it a valid array, or paste line-separated objects and the converter will attempt to parse. NDJSON is a common log format and converts cleanly to CSV.
Does the converter handle very large JSON?
It runs client-side in your browser, so practical limit depends on your device memory. 10–50 MB JSON typically works well. For multi-GB datasets, use a command-line tool like `jq` or pandas.
Is my data uploaded anywhere?
No — everything runs in your browser. Paste sensitive customer data, API tokens, or financial records with confidence. We do not log, store, or transmit your input.
Pro Tip
Use semicolon delimiter when your data contains commas (European number format, addresses, sentences) to avoid quoting overhead and produce a cleaner-looking CSV. Most European Excel installations expect semicolons by default; US Excel can be configured to use them under Data → Text to Columns or Region settings.