How to Convert Excel (XLSX) to JSON Online and With Code

Why Convert Excel to JSON

Excel is where business data lives. JSON is where APIs, apps, and databases expect it to arrive. Converting XLSX to JSON turns a spreadsheet into a shape that developers can consume without manual cleanup every time.

Done right, the JSON keeps types intact, preserves IDs as strings, and skips the empty rows Excel leaves behind.

Pick the Right Path

Match the tool to the frequency of the job.

Step-by-Step: In the Browser

The fastest workflow uses two Convert CSV Online tools.

• Open the Excel to CSV Converter.
• Upload the .xlsx and pick the sheet.
• Download the resulting .csv.
• Open the CSV to JSON Converter and drop the CSV in.
• Download the .json and inspect in your editor.

Step-by-Step: With Python

pandas plus openpyxl reads XLSX directly.

import pandas as pd

df = pd.read_excel("orders.xlsx", dtype={"order_id": str})
df.to_json("orders.json", orient="records", force_ascii=False, indent=2)

sheets = pd.read_excel("workbook.xlsx", sheet_name=None, dtype=str)
import json
with open("workbook.json", "w") as f:
    json.dump({name: df.to_dict(orient="records") for name, df in sheets.items()}, f, indent=2)

records = df.to_dict(orient="records")
nested = [
    {
        "order_id": r["order_id"],
        "customer": {"name": r["customer_name"], "email": r["customer_email"]},
    }
    for r in records
]

Step-by-Step: With Node.js

SheetJS handles XLSX reading and JSON conversion.

import * as XLSX from "xlsx";
import fs from "node:fs";

const wb = XLSX.readFile("orders.xlsx");
const ws = wb.Sheets[wb.SheetNames[0]];
const rows = XLSX.utils.sheet_to_json(ws, { defval: "", raw: false });
fs.writeFileSync("orders.json", JSON.stringify(rows, null, 2));

Types, Dates, and IDs

The three columns that break most Excel → JSON conversions.

Cleaning Before Conversion

Ten minutes of cleanup save hours of debugging.

• Delete summary rows at the top or bottom.
• Remove blank rows and unmerge merged cells.
• Rename headers to snake_case for easier JS/Python access.
• Verify one type per column.

Real-World Examples

Common shapes of the workflow.

Common Mistakes

The bugs that show up repeatedly.

• Auto-casting IDs to numbers and losing leading zeros.
• Missing sheet name and getting only the first tab.
• Assuming JSON output is nested when the spreadsheet is flat.
• Ignoring merged cells that become nulls.
• Emailing JSON with sensitive data instead of using secure sharing.

Best Practices

Habits that keep JSON output trustworthy.

• Type all IDs as strings.
• Emit ISO dates.
• Version your JSON output next to the source XLSX.
• Validate output against a JSON Schema.
• Prefer .xlsx over legacy .xls.

Why Use Convert CSV Online?

Convert CSV Online is free, browser-based, and requires no account for everyday conversions. Chain Excel to CSV → CSV to JSON, or clean up in the Online XLSX Editor first. Client-side workflows run on Windows, macOS, and Linux browsers.

Conclusion

Excel-to-JSON is a common bridge between business data and code. Clean the sheet, force types, and pick the workflow that matches how often you will re-run the conversion.