API JSON to CSV — Export API Response Data to Spreadsheet
Convert JSON arrays to CSV — nested flattening · custom delimiter · live preview · Excel download · 100% Free
Exporting API data to spreadsheets is one of the most common developer tasks — someone always needs the data in Excel. This tool takes any REST API JSON response and converts it to a clean CSV ready for analysis. Handles paginated responses, nested objects (flattened), and arrays of records. No server-side processing — your API data stays private.
What is JSON to CSV Conversion?
JSON to CSV conversion transforms JavaScript Object Notation (JSON) data into Comma Separated Values (CSV) — a flat, plain-text format that can be opened in Microsoft Excel, Google Sheets, LibreOffice Calc, or imported into any database. CalcNation's JSON to CSV converter handles nested objects, arrays, inconsistent keys, and custom delimiters — all 100% in your browser.
Options Explained
Flatten Nested JSON — Converts nested objects to dot-notation columns. E.g. { "address": { "city": "X" } } becomes the column address.city. Flatten Arrays — Expands array items to separate columns: tags[0], tags[1]… Delimiter — Choose comma (standard), semicolon (European Excel), tab (TSV for Excel paste), pipe, or a custom character. Header Row — Toggle whether the first CSV row contains column names.
Frequently Asked Questions
How do I export a paginated API to a complete CSV?
For paginated APIs: (1) Manual: export each page separately, merge CSVs in Excel. (2) Script: loop through pages: while(hasNext) { fetch page; append to CSV }. Node.js example: const allRows = []; while(page <= totalPages) { const { data } = await fetch(url+"?page="+page); allRows.push(...data); page++; } Convert allRows to CSV. (3) Tools: Postman collection runner, Insomnia.
How do I extract a nested array from an API response for CSV?
If API returns {"meta":{...},"items":[...]} and you want only items as CSV: this tool lets you set root path to "items" before conversion. Equivalent in JavaScript: const csvData = apiResponse.items; then convert. In jq: cat response.json | jq ".items" > items.json then convert items.json to CSV.
Can I fetch API JSON and convert to CSV directly in the browser?
Yes — modern browsers support fetch() from any JavaScript console: fetch("/api/data").then(r=>r.json()).then(data=>copy(JSON.stringify(data))). This copies API JSON to clipboard — paste here for CSV conversion. Note: CORS policies may prevent fetching from external domains. Use Postman or curl for external APIs.
What tools automate REST API to CSV export for reporting?
Options by complexity: (1) No-code: Zapier, Make (Integromat) — API to Google Sheets automatically. (2) Low-code: Retool, Appsmith — build internal data export tools. (3) Code: Python requests + pandas, Node.js axios + json2csv. (4) ETL tools: Airbyte, Fivetran — enterprise API to data warehouse pipelines. Choose based on frequency and volume.