LibreOffice
A free, open-source office suite (Writer, Calc, Impress) that can convert between Word, Excel, PowerPoint and PDF — widely used as a server-side document conversion engine.
LibreOffice is the most capable free alternative to Microsoft Office, maintained by The Document Foundation. Besides its user-facing applications — Writer, Calc, Impress, Draw — LibreOffice also runs in "headless" mode on servers, acting as a faithful converter between virtually every office document format.
Why LibreOffice matters for PDF tools
Converting Word, Excel, or PowerPoint documents to and from PDF is a deceptively hard problem. The file formats (DOCX, XLSX, PPTX) are complex, full of edge cases, and constantly evolving. Writing a custom converter is years of work. Using LibreOffice headless solves it:
- Industry-standard rendering — LibreOffice is battle-tested against billions of real-world Office documents
- Faithful preservation — fonts, layouts, tables, charts, and headers typically survive the round-trip
- Zero licensing cost — LGPL licensed, suitable for SaaS deployment
How PDF Genie uses LibreOffice
All of our Office ↔ PDF conversions run through a headless LibreOffice instance on the server:
- Word to PDF (DOC, DOCX, ODT, RTF)
- PDF to Word (DOCX output)
- Excel to PDF (XLS, XLSX, ODS, CSV)
- PowerPoint to PDF (PPT, PPTX, ODP)
- PDF to PowerPoint and PDF to Excel
Trade-offs
LibreOffice is not perfect. Complex layouts (multi-column, heavy tracked changes, elaborate macros, VBA code) may shift when round-tripped through LibreOffice. For pristine fidelity on complex documents, Microsoft's own conversion (via Word or Graph API) is stronger. For the vast majority of everyday documents — resumes, reports, spreadsheets, decks — LibreOffice delivers a faithful result at zero license cost.