Excel to JSON with typed values and nested keys

Spreadsheets are where product catalogs, translations, price lists and configuration tables are maintained. Applications, however, want JSON. Copying cells into a code editor is slow and error prone, and generic converters turn every value into a string.

XlsConverter maps headers to keys, infers types per column, and can build nested objects from dotted header names. Coming from the binary format? See XLS to JSON. Going the other way? Use JSON to Excel.

How to convert Excel to JSON in three steps

1. 1Upload your .xlsx, .xlsm or .xls workbook.
2. 2Pick the sheet, the header row and the JSON shape.
3. 3Convert and download the JSON file, or receive it through the API.

Keeping types correct when spreadsheet cells become JSON values

JSON distinguishes numbers, strings, booleans and null, and the application reading it usually cares. A price column should be 19.9, not "19.9", while a SKU column of 00451 must stay a string. We infer the type for each column from all of its values, not cell by cell, so one stray text cell does not make half a column strings and the other half numbers. You can override any column.

Excel stores dates as serial numbers counted from 1900, so a naive export gives you 46000 instead of a date. We read the cell format and write 2025-12-09 style ISO strings, which every JSON parser and database accepts. Booleans written as TRUE and FALSE in Excel become true and false, and percent cells are written as their decimal value.

Flat sheets often hide structure: columns named variant.1.color or seo.title. With nested keys turned on, these become arrays and objects, which saves a transformation step in your code. For a flat file that a data team can load directly, Excel to MySQL or Excel to PostgreSQL may suit better than JSON.