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Offline office suite for small business

Office-style offline documents, spreadsheets and slides with real exports and no subscription trap.

Coming soon

Affordable premium, offline-first software. Local-first; no subscription trap. Culltron Max and Ultra X27 (Ultra X27 generation). Affiliate disclosure.

What this covers

An office suite should keep working when the internet does not. Office Max covers documents, spreadsheets and slides on your own machine, and PDF Max handles the PDF side.

The Culltron tools for this job

Office Max

Documents, spreadsheets and slide decks in one offline-first desktop app.

  • A rich-text document editor with a structured citation registry, deterministic numbering and a bibliography you can refresh.
  • A spreadsheet formula engine running in the app, with 103 user-facing functions, A1 ranges and dependency recalculation that detects circular references.
  • A slide editor with a Present mode.
  • DOCX and XLSX import with a review step. Before a copy is made, the app shows what will be lost and what is supported. The original file is kept unchanged and is verified by checksum.
  • DOCX and XLSX export of the supported subset, plus local drafts and autosave.
  • A signed offline licence lease, so you can keep working without a connection.

Limits: Imports cover a supported subset; Word citation fields and syncing with external reference managers are not claimed. Import reports are local checksums, not a guarantee of full fidelity.

PDF Max

A local PDF workstation. Nothing is uploaded unless a separate connected workflow says so explicitly.

  • A viewer with page thumbnails, zoom, rotate, jump, keyboard navigation and text search.
  • Organise, rotate, delete, crop and extract exact page ranges. Merge files, turn images into a PDF, export pages to PNG and extract text.
  • Edit metadata and add watermarks and page numbers.
  • Inspect and fill AcroForm fields, author fields after review, and optionally flatten. Add bookmarks and page labels.
  • Local preflight checks for structure, accessibility and print, plus bounded OCR to create searchable copies.
  • AES-256 password encryption and authorised decryption, available when qpdf is installed. Each change writes a separate copy and a receipt.

Ultra X27: adds stamps, presets for watermarks and page numbers, appearance-only signature marks, metadata cleaning, three lossless optimisation profiles, batch merge/split/watermark/numbering, and document binders.

Limits: Production edits refuse dynamic XFA forms and PDFs that already carry signatures rather than silently invalidating them. Signature marks are visual and are not digital signatures.

Who it is for

How it works

  1. Each Max app is a separate desktop product built on Culltron's shared, hardened platform.
  2. Files and records stay in a local folder on your machine, and the core tools work offline.
  3. A signed licence lease unlocks the paid edition. Ultra X27 adds advanced features that the server enforces.
  4. When you change a file, the app writes a new copy, often with a checksum receipt, instead of silently overwriting your original.

Frequently asked questions

Is it compatible with Microsoft Office files?

It imports and exports DOCX and XLSX for a supported subset of features. Before you edit an imported file, it shows what might be lost.

How capable is the spreadsheet?

It has 103 functions, A1 ranges and dependency recalculation that detects circular references.

Is there real-time co-editing?

Not in the desktop app.

How is it licensed?

Through a signed offline lease, so it keeps working without a connection.

Release status: built and tested in the repository. A public download appears only after signing, checksum verification and release approval; see Downloads.