CSV to JSON Converter
Paste CSV, TSV or any delimited text and get valid JSON instantly. Handles quoted fields, embedded commas, escaped quotes and multi-line values. Your data never leaves your browser.
"") inside a single value. Auto-detect counts delimiter occurrences in the first few lines to pick the most likely one. Everything runs locally — no server, no upload.
Finding This CSV to JSON Converter Useful?
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Get the Standalone VersionWhat Is a CSV to JSON Converter?
A CSV to JSON Converter reads comma-separated (or otherwise delimited) text and produces a JSON document. Spreadsheets export CSV; APIs and JavaScript applications consume JSON. This tool bridges the two formats: it parses the CSV into rows and fields, optionally uses the first row as object keys, then serialises the result as a JSON array. It handles quoted fields, escaped quotes and embedded line breaks, so spreadsheets with commas inside cells work correctly. Everything runs in your browser with no server involved.
Key Features
RFC 4180 CSV Parser
Quoted fields, escaped double quotes (""), embedded commas and embedded newlines all parse correctly.
Auto-Detect Delimiter
Comma, semicolon, tab or pipe — the parser samples the first few lines and picks the most consistent choice.
Three Output Shapes
Array of objects keyed by header, array of arrays for raw rows, or a top-level object keyed by the first column.
Type Detection
Strings like 42, 3.14, true, false and null are converted to their JSON types, not left as strings.
Live Stats
Row count, column count, input and output byte sizes, and the compression ratio between CSV and JSON.
Nothing Leaves Your Browser
No network requests, no analytics, no server. Everything — parsing, conversion, download — happens locally.
How to Use the CSV to JSON Converter
- Paste your CSV — drop it into the input box, or use the file picker to load a
.csv,.tsvor.txtfile. - Choose a delimiter — auto-detect usually gets it right; override it if your file uses a custom separator.
- Pick an output shape — array of objects is the common case; array of arrays preserves raw rows; keyed output is useful when the first column is an ID.
- Toggle options — trim whitespace, skip empty lines, detect types and pretty-print as you prefer.
- Click Convert to JSON — the JSON appears instantly in the right-hand panel with stats below.
- Copy or download — use Copy JSON or Download .json to grab the result.
Practical Use Cases
Spreadsheet Export
Turn a Google Sheets or Excel CSV export into JSON for a web app, script or API request.
Data Pipeline Prep
Convert a CSV to JSON before loading it into MongoDB, Firestore, or any document store.
API Testing
Produce request bodies in JSON from tabular data when manually testing an endpoint.
Static Site Data
Convert a CSV of blog posts, products or locations into JSON for a static site generator.
Documentation Examples
Turn a CSV sample into a clean JSON snippet for a README or tutorial.
AI/LLM Inputs
Feed structured JSON to a model that expects JSON input rather than a raw CSV string.
Important Notes and Limitations
A few honest caveats:
• Duplicate headers overwrite each other. If the header row contains the same name twice, the later column wins in the object output. Rename duplicates in your CSV first if this matters.
• Auto-detect works on the first ten lines. If your file has a delimiter that only appears after line 10, or the first rows are unusual, auto-detect may guess wrong. Switch to a manual delimiter in that case.
• Type detection is heuristic. A postal code like 01234 will be read as the number 1234 if type detection is on, losing the leading zero. Turn type detection off for ID-like columns.
• Very large files are read into memory. Files of a few megabytes are fine; tens of megabytes may make the page feel slow for a moment.
• Malformed CSV will still produce output. If a quote is unclosed, the parser treats the rest of the file as one field. The stats will show fewer rows than expected — check the preview panel if something looks off.
• Encoding is assumed to be UTF-8. Files saved in legacy encodings (Windows-1252, Shift-JIS, etc.) may show garbled characters for non-ASCII text. Convert to UTF-8 first.
Frequently Asked Questions
Yes. A field wrapped in double quotes can contain the delimiter, line breaks, and escaped quotes (written as two double-quote characters in a row). This is the RFC 4180 standard for CSV and is what spreadsheet exports produce when a cell contains a comma or newline. Fields without quotes are split on the delimiter as expected.
Three: Array of objects uses the first row as property names and produces [{"name":"Alice",...}, ...]. Array of arrays ignores headers and gives you the raw rows as [["name","age"], ["Alice","30"], ...]. Object keyed by first column produces {"Alice": {...}, "Bob": {...}} which is convenient when the first column is a unique identifier.
Because type detection converted the field to a number. The string "01234" becomes the number 1234, losing the leading zero. Turn type detection off in the Options row and re-convert — every field will stay a string. This is the right setting for postal codes, phone numbers, account numbers and any column where the leading zeros matter.
Yes. Choose "Tab" from the delimiter dropdown, or leave it on auto-detect — the parser checks for tabs alongside commas, semicolons and pipes. TSV files often have no quoting at all, which this tool handles without issue.
No. The parser runs entirely in JavaScript in your browser. There is no backend and no network request containing your data. You can confirm this by opening your browser's network panel while using the tool — no request is made. The standalone edition works completely offline.
About the Author — GenieDevs
Get the Standalone Version
CSV to JSON Converter — Standalone Edition
One self-contained HTML file with the full converter inside. Keep it on your machine, run it from a USB stick, or use it on an air-gapped computer — no internet connection needed.
Final Takeaway
Converting CSV to JSON is one of those small tasks that comes up constantly when you move data between a spreadsheet and an application. This tool handles the tricky parts — quoted fields, embedded newlines, custom delimiters and type detection — without needing a library or a server. It runs entirely in your browser, it is fast on files of a few megabytes, and it produces clean JSON you can paste straight into a script, an API request, or a database import.