view an xlsx file inside IntelliJ IDEA, without Excel

Since 2024.1, IntelliJ IDEA with Database Tools opens a workbook in the editor through a read-only data loader; JetBrains badges that help page Ultimate, and its note says Database Tools support is limited in IntelliJ IDEA without the Ultimate subscription. The Community edition of 2025.2 and older treats the workbook as a binary file. Without the loader, a plugin opens it in the IDE, or Open In hands it to a spreadsheet app.

free plugins

ExcelReader, free, parses .xls, .xlsx and .csv files and filters what it finds, and its newest Marketplace reviews are worth reading against your IDE build first. Syncfusion's Document Viewer, also free, opens workbooks as well as Word and PDF files, and lets you make an edit and save it.

XLSX Lens: installing and opening

XLSX Lens opens the workbook in an editor tab, streamed, and neither writes to it nor locks it. It runs in IntelliJ IDEA, PyCharm and every other JetBrains IDE on 2024.2 or newer, Android Studio from Ladybug.

Install XLSX Lens from the JetBrains Marketplace, then double-click the workbook in the project tree. One streaming pass spills rows to a scratch index, so the first page renders while a 500,000-row sheet is still loading and memory stays flat. Before a release ships we run it on IntelliJ IDEA Community 2024.2, IntelliJ IDEA 2026.2 and Android Studio 2026.1.

XLSX Lens in IntelliJ IDEA: a half-million-row sheet paged 100 rows at a time, the Pro actions in the toolbar — half-million-rows.xlsx: rows 1 to 100 of 499,999 on screen, the sheet list on the left, the Pro actions in the toolbar.

reading a sheet

Every sheet is listed with its size in rows and columns once read, hidden ones named as hidden. Merged cells render. A date cell is read by the date system the workbook declares, 1900 or 1904, and the builtin and the common custom number formats are applied, currency and accounting among them. Ctrl+F searches across every row over values, formatted text and formulas, and the cell inspector then shows one cell whole, the value beside the raw stored text, the formula and the format pattern.

A sheet pages to its last row, with no row cap. Formula cells show the results cached in the file, since nothing is recalculated. A legacy .xls does not open at all, and .csv is never claimed away from the editor that already has it.

what Pro adds

Pro writes a sheet, the search matches or the current filtered view out as CSV, JSONL, Markdown, Parquet or a workbook copy, and it profiles the columns into a report. It also sorts and filters every row rather than the loaded page, and it diffs two workbooks sheet by sheet with the differing cells marked. Formula view and a reload when the file changes on disk are Pro as well.

The viewer is free and stays free. Pro is a subscription for this plugin: USD 2.90 a month or USD 29 a year for individual use. For organizations it is, per user, USD 5.80 a month or USD 58 a year.

A workbook that will not open is a bug to report: Report an XLSX Lens Problem, in the Help menu, opens a prefilled new issue in your browser for you to read before you post. Suggestions for the plugin go to support@twilightventures.dev.

handing it to a spreadsheet app

Right-click the file in the Project tool window and choose Open In, then Associated Application: the IDE passes it to whatever app the system opens .xlsx files with, Excel or LibreOffice Calc among them. That needs such an app on the machine, and the workbook is read outside the IDE. A workbook that opens as garbled text instead means the .xlsx pattern was once added to a text file type; remove it under Settings, Editor, File Types.

Install from the JetBrains Marketplacefree to read; the Pro trial runs 30 days