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How to Convert Excel to JSON and Back With Python (Free Tool)

Convert Excel to JSON and back with Python tutorial showing pandas openpyxl JSON conversion Excel automation and data exchange
Easily convert Excel spreadsheets to JSON format and transform JSON data back into Excel using Python. This tutorial explains how to read Excel files with pandas, export worksheets as JSON, import JSON into structured Excel workbooks, preserve data types, automate conversions, and handle nested or complex datasets. Ideal for developers, data analysts, API users, automation engineers, and Excel professionals who need to exchange data between spreadsheets and applications efficiently.

Key takeaways

  • The reliable way to convert between Excel/CSV and JSON is a script, not copy-paste or a sketchy online converter.
  • Excel ⇄ JSON Converter is free and open-source (MIT), built in Python with pandas.
  • It works both directions and detects which from the file extension.
  • Nested JSON like contact.email is flattened into columns automatically.
  • Supports JSON Lines (NDJSON) with --lines for streaming/log formats.

To convert Excel to JSON, run a free tool called Excel ⇄ JSON Converter, which turns a spreadsheet into a JSON array in one command — and converts JSON back into a spreadsheet just as easily. It auto-detects the direction from the file extension and flattens nested JSON into clean columns, so you never have to reformat data by hand.

Why converting between spreadsheets and JSON is a constant chore

Spreadsheets and JSON are the two formats data lives in. Your data is in Excel, but an API, a web app, or a config file needs JSON. Or an API returns JSON and you need it in a spreadsheet to read and edit. Doing this by hand — or pasting sensitive data into a random online converter — is slow and risky.

A local script converts either way in one command, keeps your data private, and handles the awkward parts (like nested objects) for you.

people.xlsx Excel ⇄ JSON both directions people.json [ { "id": 1, "name": "Alice", "city": "London" }, { ... } ]
One tool, both directions — spreadsheet to JSON array, and JSON back to a clean table.

How to install the tool (2 minutes)

You need Python 3.9 or newer. Clone the repository and install its dependencies:

git clone https://github.com/Synth88Labs/excel-tool-json.git
cd excel-tool-json
pip install -r requirements.txt

Get Excel ⇄ JSON Converter on GitHub (free)

How to convert Excel to JSON — step by step

Convert a spreadsheet to JSON

Point the tool at a .csv or .xlsx file; it writes a JSON array:

python convert_json.py people.xlsx -o people.json

Each row becomes an object:

[
  { "id": 1, "name": "Alice", "email": "alice@example.com", "city": "London" }
]

Convert JSON back to a spreadsheet

Give it a .json file; it writes an Excel or CSV file. Nested objects are flattened into dotted columns:

python convert_json.py people.json -o people.xlsx

So { "contact": { "city": "London" } } becomes a column named contact.city.

Convert to JSON Lines (NDJSON)

For streaming formats and log pipelines, output one object per line with --lines:

python convert_json.py people.csv -o people.jsonl --lines
Tip: You don't have to specify the direction — the tool figures it out from the input file's extension. A .csv/.xlsx input converts to JSON; a .json/.jsonl input converts from JSON.

Which direction does what

InputOutputWhat happens
.csv / .xlsx.jsonRows become an array of objects
.csv / .xlsx.jsonl (with --lines)One JSON object per line
.json / .jsonl.xlsx / .csvObjects become rows; nested keys flattened to columns

Real work use cases

  • Feeding APIs and apps — turn a spreadsheet into JSON a system can import.
  • Reading API responses — convert a JSON export into a spreadsheet you can filter and edit.
  • Config & seed data — maintain data in Excel, ship it as JSON.
  • Log processing — read JSON Lines logs into a table for analysis.
  • Data handoffs — give developers JSON and non-technical teammates a spreadsheet, from one source.

Common mistakes to avoid

  • Deeply nested arrays. Flattening works cleanly for nested objects; lists inside a record are kept as-is, so restructure very complex JSON first.
  • Expecting a fixed direction. The tool converts based on the input extension — name your files accordingly.
  • Encoding surprises. Output JSON is UTF-8 and preserves non-English characters; make sure whatever reads it also uses UTF-8.
  • Huge files in memory. Like most converters, it loads the file into memory — for very large data, split it first.
🔗 Big JSON or spreadsheet to handle? Split it into pieces with the free Excel Splitter, or tidy the data first with the Excel Data Cleaner.

Frequently asked questions

How do I convert an Excel file to JSON?

Run python convert_json.py yourfile.xlsx -o output.json. The tool reads the sheet and writes a JSON array where each row is an object.

How do I convert JSON to Excel or CSV?

Run python convert_json.py yourfile.json -o output.xlsx (or output.csv). Nested objects are flattened into dotted column names.

Can it handle nested JSON?

Yes. Nested objects like {"contact": {"city": "London"}} become a column named contact.city when converted to a spreadsheet.

Does it support JSON Lines (NDJSON)?

Yes. Add --lines when writing JSON to emit one object per line, and the tool reads .jsonl input automatically.

Is Excel ⇄ JSON Converter free?

Yes. It's open-source under the MIT license, free for personal and commercial use. The source is on GitHub.

Do I need Excel installed?

No. It reads and writes files with Python libraries, so it works without Microsoft Excel installed.

Is my data sent anywhere?

No. It runs entirely on your machine — nothing is uploaded, unlike online converters.

Summary

Moving data between spreadsheets and JSON shouldn't mean copy-paste or risky online tools. Excel ⇄ JSON Converter turns Excel/CSV into JSON and back in one command — both directions, nested objects flattened, JSON Lines supported. It's free, open-source, private, and works without Excel installed.

Download Excel ⇄ JSON Converter free on GitHub