Interchange you can execute.

XLSX round-trip workbench

Edit any cell through the shell chrome, then download the document, re-import your own, or run the round-trip in place.

• Orders + Invoice sheets
• 9 formulas — per-row & cross-sheet
• currency formats
• merged footer
• frozen header row

Committed independent fixtures

Bytes produced by other software, committed with full provenance, and hashed in your browser before use — load any of them into the workbench above.

provenance manifest: packages/xlsx/test/fixtures/manifest.json

• LibreOffice 26.2.4.2hashing…

  sheetwrite-libreoffice-positive.xlsxcb7cba1a9a804d71…

  • strings
  • numbers
  • date-formatted numeric cells
  • surrounding whitespace
  • multiple data rows
  Load in workbench
• LibreOffice 26.2.4.2hashing…

  libreoffice-rich.xlsx75fb643cafcbe660…

  • ordinary formulas
  • bold font and RGB font color
  • solid fill
  • per-side borders
  • horizontal alignment
  • currency number format
  • merged cells
  • decimal validation
  • legacy note/comment
  • hidden worksheet
  • active worksheet
  • frozen row and column
  • named range

  Manifest-documented warning: unsupported-feature: hidden worksheet visibility

  Load in workbench
• LibreOffice 26.2.4.2hashing…

  libreoffice-metadata.xlsx5a676a11d56ae1e4…

  • LibreOffice-preserved hidden Sheetwrite metadata worksheet
  • documentId
  • version
  • stable sheet ids and column metadata
  • native formula, validation, comment, merge, view, and named-range parts

  Manifest-documented warning: unsupported-feature: hidden worksheet visibility

  Load in workbench

Producer verification status

• LibreOffice 26.2.4.2Verified here
  Scope and limitations

  Committed LibreOffice-produced workbooks import on this page, in your browser, with checksums verified against the fixture manifest.

  packages/xlsx/test/fixtures/manifest.json
• Sheetwrite round-tripVerified here
  Scope and limitations

  The workbench below exports this document to .xlsx bytes and re-imports them live; formulas, formats, the merge, and frozen rows survive.

  toXlsxWorkbook / fromXlsxWorkbook on this page
• Microsoft ExcelSuite verified
  Scope and limitations

  5 Excel-produced workbooks from the Apache POI test corpus (commit 913c78891b) are checksum-pinned and verified in the conformance suite. Those bytes are not redistributed here, so this page does not run them. Not yet verified from Excel bytes: hidden worksheet, Sheetwrite metadata resave.

  packages/xlsx/test/fixtures/external-corpus.json
• Google SheetsSuite verified
  Scope and limitations

  1 genuine Google Sheets-exported workbook (google-sheets-public.xlsx) is checksum-pinned and verified in the conformance suite: shared strings, ten worksheets, 230 formulas, cell styles, frozen rows, exact drawing and reserved-fill warnings. Licensing does not permit redistributing the bytes here, so this page does not run them. Not yet verified from Google Sheets bytes: dates, merges, validations, notes, hidden active sheet, defined names, Sheetwrite metadata resave.

  packages/xlsx/test/fixtures/external-corpus.json

Fidelity warnings, not silent loss

Every import and export reports what it could not preserve as structured XlsxWorkbookWarning records — coded, per sheet, per cell. Warning codes →

CSV and TSV, hardened

Delimited exports neutralize formula-injection payloads before a cell ever reaches a spreadsheet that would execute them.

Resource limits and hostile input

Ceilings are enforced before anything allocates, and hand-authored hostile OPC/SpreadsheetML packages are rejected with typed errors. Resource limits →

• byte ceiling
• entry ceiling
• dimension ceiling
• compression-ratio ceiling
• cell ceiling
• AbortSignal honored

The XLSX codec is an optional package

@sheetwrite/core ships no XLSX implementation — workbook interchange throws a typed error until a host registers a backend. This page loads @sheetwrite/xlsx/register lazily on the first XLSX action; CSV/TSV interchange needs no optional package at all.