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.

Calkulon makes complex calculations simple — built for students and everyday problem-solvers.

1. 1Step 1 — Paste your JSON into the input area (array of objects works best)
2. 2Step 2 — Calculator validates JSON structure and surfaces parse errors with helpful hints
3. 3Step 3 — Choose delimiter (comma is default; semicolon for European Excel; tab for TSV)
4. 4Step 4 — Converter auto-detects unique keys across all objects to build column headers
5. 5Step 5 — Each object becomes a row; missing keys produce empty cells; nested values flatten with dot notation
6. 6Step 6 — Output appears in a copy-friendly text area with row and column count
7. 7Step 7 — Copy to clipboard and paste into Excel, Google Sheets, or save as .csv file

• !Trailing commas in JSON (invalid per spec; many editors mistakenly allow it)
• !Single quotes instead of double quotes (JSON requires double quotes for strings)
• !Unescaped backslashes or newlines inside strings
• !Forgetting that key order in JSON is not guaranteed across objects — columns reflect first-seen order
• !Loading European CSV (semicolon-delimited) into US Excel without changing the Region setting