A free, open-source Windows app that converts between 244 registered formats in 17 categories — images, documents, spreadsheets, e-books, audio, video, archives, fonts, CAD, 3D models and more — with a PDF editor, Signature Studio, PDF tools and folder utilities built in.
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File conversion · PDF editing · File utilities · Install · Build
| 🔁 Convert | Drop files on the Quick panel, right-click them in File Explorer, or set up watch folders. Many conversions work as soon as Foldex is installed; audio, video and some office, markup and e-book conversions need an optional engine you download once. |
| 📝 Edit PDFs | Retype a line of existing text, fill standard PDF forms, sign (visually or with a certificate), annotate, rearrange pages, then merge, split, compress, password-protect or OCR. |
| 🗂️ Tidy folders | Find duplicate files, the largest files and files with the wrong extension; strip picture metadata; compare two files; rename many files at once. |
Foldex's format registry lists 244 formats across 17 categories. 169 of them can be written as output; the other 75 are read as input only (for example camera RAW, Apple Pages / Numbers / Keynote and RAR) and are converted to something else.
A format being in the registry doesn't mean every pair of formats converts. Foldex only offers targets that one of its engines can actually produce for the files you picked.
 |
How you convert Quick panel — hold Ctrl while dragging files in File Explorer. The panel opens at your cursor with the targets for those files; drop them on one. The shortcut can be changed in Settings → Shortcuts. File Explorer — right-click files and choose Convert with Foldex (on Windows 11 it's under Show more options, and in Send to). Home — drop files on the drop zone or use Browse files / Browse folder; progress shows in the task queue. Watch folders — files that land in a folder are converted automatically with a preset. Converted files are saved as new files, next to the originals unless you choose another folder. |
| Category | Formats | Examples |
|---|---|---|
| Images | 36 | PNG, JPG, WEBP, HEIC, AVIF, JPEG XL, TIFF, GIF, ICO, PSD, ICNS; camera RAW, DICOM, OpenEXR (read only) |
| Vector graphics | 12 | SVG, SVGZ, EPS, PS, EMF, WMF, ODG; AI, CDR, VSD (read only) |
| 1 | ||
| Documents | 23 | DOCX, DOC, ODT, RTF, EML; Pages, WPS, WordPerfect, Outlook MSG (read only) |
| Hangul (HWP) | 2 | HWP, HWPX |
| Spreadsheets | 13 | XLSX, XLS, ODS, CSV, TSV; Numbers (read only) |
| Presentations | 11 | PPTX, PPT, ODP, PPSX; Keynote (read only) |
| Text and markup | 14 | TXT, Markdown, HTML, LaTeX, reStructuredText, AsciiDoc, Jupyter, Typst |
| Data | 6 | JSON, JSON Lines, YAML, TOML, XML, vCard |
| E-books and comics | 24 | EPUB, KEPUB, MOBI, AZW3, FB2, CBZ; CBR, CHM (read only) |
| Video | 22 | MP4, MOV, MKV, WEBM, AVI, WMV, MPEG, TS |
| Audio | 30 | MP3, M4A, AAC, WAV, FLAC, OGG, OPUS, WMA, AIFF |
| Archives | 28 | ZIP, 7Z, TAR, TAR.GZ; RAR, ISO, CAB, DMG (read only) |
| CAD | 2 | DWG, DXF |
| Fonts | 5 | TTF, OTF, WOFF, WOFF2, EOT |
| Subtitles | 9 | SRT, ASS, WebVTT, SAMI, LRC, TTML |
| 3D models | 6 | GLB, glTF, STL, OBJ, 3MF, PLY |
The full list, with every extension, is in FormatRegistry.cs; which
engine handles what is in docs/ENGINES.md.
Most conversions use engines that are built in or installed with Foldex (ImageMagick, PDFsharp, PDFium, 7-Zip, rhwp and Foldex's own document, e-book, data, subtitle, font, CAD and 3D converters). Some need an optional engine:
| Optional engine | Download (approx.) | Needed for |
|---|---|---|
| FFmpeg | 100 MB | All audio and video conversions, video ↔ animated GIF, and writing HEIC images |
| LibreOffice (with Java and H2Orestart) | 420 MB | Older and less common office formats: DOC, XLS, PPT, RTF and OpenDocument to PDF and to each other, and the read-only office formats (Pages, WordPerfect, …) |
| Pandoc | 42 MB | Markup formats such as LaTeX, reStructuredText, Org and AsciiDoc ↔ DOCX/ODT/HTML/Markdown, and Markdown → PPTX |
| Ghostscript | 20 MB | EPS / PS → PDF, PDF → EPS / PS, PostScript-based AI files |
| Calibre | 225 MB | Rare e-book formats (LIT, LRF, CHM, PDB, …) and EPUB → MOBI / AZW3 |
On first start Foldex asks which of these to download, and you can install or remove them at any time in
Settings → Engines. A conversion that needs a missing engine is marked Needs FFmpeg (or the engine it needs)
instead of being attempted. Downloads come from pinned addresses and are checked against a SHA-256 hash before they're
unpacked into %LOCALAPPDATA%\Foldex\engines. Microsoft Office isn't needed or used: DOCX, XLSX and PPTX → PDF work
with the built-in engines.
| From → to | Engine |
|---|---|
| HEIC → JPG, PNG → WEBP, PSD → PNG | Built in |
| DOCX → PDF, XLSX → PDF, Markdown → DOCX | Built in (no Office needed) |
| EPUB → PDF, DWG → PDF, STL → OBJ, TTF → WOFF2 | Built in |
| ZIP / 7Z / RAR → folder, files → ZIP | Built in (7-Zip is installed with Foldex) |
| MP4 → MP3, MOV → MP4, MKV → WEBM | FFmpeg |
| DOC → DOCX, PPT → PDF | LibreOffice |
| LaTeX → DOCX | Pandoc |
| EPS → PDF | Ghostscript |
| LIT → EPUB | Calibre |
- Edit existing text, line by line — click a line with the ✎ tool and retype it. The old text is removed from the page and the new text is written at the same position, size and colour, in the closest installed font. Foldex reads the saved file back to check the change; if a page can't be changed safely, nothing is saved and you're told why.
- Fill forms — standard PDF forms (AcroForm): text fields, check boxes, lists and radio buttons, saved into the PDF's own form.
- Signature Studio — type your name in one of five signature styles, draw it with a mouse, pen or finger, or upload a picture of your signature (the white background can be removed). Place it on the page, then move or resize it.
- Sign with a certificate — when saving, choose a
.pfx/.p12certificate to add a digital signature (PKCS#7, SHA-256) over the whole file. - Annotate — highlight, underline and strike-out that follow the words, sticky notes, text boxes, rectangles, ellipses, lines and pictures.
- Pages — reorder by dragging thumbnails, rotate, duplicate, delete, insert pages from another PDF and export selected pages, with undo and redo.
- When saving — page numbers, header and footer, watermark, a password (AES-256) and removing document information. The original file is only changed if you save over it, and closing with unsaved changes asks Save, Don't save or Cancel.
Important
Visual signature vs. certificate signature. A typed, drawn or uploaded signature is a picture of a signature, like signing a printout — it proves nothing about who signed or whether the file changed. Sign with a certificate adds a cryptographic digital signature: PDF viewers can check who signed and whether the document was changed afterwards. The certificate signature is invisible on the page, can't be combined with a password, and has no trusted timestamp.
 Signature Studio — five typed styles (bundled fonts), a drawing pad, or an uploaded picture; four ink colours and a live preview. |
 PDF tools — results are saved as new files next to the originals. |
Merge PDFs in a chosen order · split by page ranges or every N pages · compress, with the size before and after · protect with a password (AES-256) or save an unlocked copy of a PDF whose password you know · extract text · OCR scanned PDFs into searchable PDFs using the text recognition built into Windows (it reads the languages Windows has OCR support installed for).
- Text editing works one line at a time and doesn't reflow paragraphs: a longer line runs further to the right.
- Scanned pages have no text to edit — run OCR first, or add a text box.
- Text on pages stored rotated inside the PDF, and text drawn in unusual ways, can't be changed (Foldex says so).
- Standard PDF forms (AcroForm) only — XFA forms aren't supported.
- A shape drawn over text doesn't remove the text underneath, so it isn't redaction. Pictures inside the page can't be edited. One PDF is open at a time, and printing is done from your PDF viewer.
Full details: docs/PDF_FEATURES.md.
- Find duplicates — files with exactly the same content in a folder (and its sub folders), compared by SHA-256.
- Largest files — the biggest files in a folder, to see what's using the space.
- Wrong extensions — files whose content doesn't match their extension (for example a PNG named
.jpg). - Picture metadata — view a picture's EXIF, GPS, IPTC and XMP data and save a copy without it; the copy is read back to check nothing is left.
- Compare two files — whether they have exactly the same content (SHA-256).
- Batch rename — rename many files with a pattern (
{name},{n},{date},{ext}), find and replace and a starting number, with a live preview. Existing files are never overwritten.
The scans only read your files: nothing is deleted or moved. Show opens a file's folder so you can decide yourself.
Search every tool and page with Ctrl+K · light and dark themes · English, 한국어, Polski and 简体中文 · presets for repeated conversions · runs in the notification area and can start when you sign in (Settings → General).
| File | What it is |
|---|---|
Foldex-1.0.0-win-Setup.exe |
Installer (Windows 10 version 1809 or later, or Windows 11, 64-bit) |
Foldex-1.0.0-win-Portable.zip |
Portable version: unzip it anywhere and run Foldex.exe |
Foldex-1.0.0-SHA256SUMS.txt |
SHA-256 checksums of the two files above |
-
Download the installer (or the portable ZIP) from the Releases page.
-
Check the file before running it. In PowerShell, in your Downloads folder:
Get-FileHash .\Foldex-1.0.0-win-Setup.exe -Algorithm SHA256
The hash must match the line for that file in
Foldex-1.0.0-SHA256SUMS.txton the release page. -
Run the installer and start Foldex from the Start menu. On first start it asks which optional engines to download (you can skip this and add them later in Settings → Engines).
Warning
The installer isn't code-signed yet, so Windows SmartScreen may show "Windows protected your PC". Only continue (More info → Run anyway) if you downloaded the file from this repository's Releases page and its SHA-256 hash matches the published checksum. If either doesn't check out, delete the file.
| Shortcut | Action |
|---|---|
| Ctrl+K | Search tools and pages |
| Hold Ctrl while dragging files in File Explorer | Open the Quick panel at the cursor |
| Ctrl+O / Ctrl+S / Ctrl+Shift+S | Open / Save / Save as (PDF editor) |
| Ctrl+W | Close the PDF |
| Ctrl+Z / Ctrl+Y | Undo / Redo |
| Ctrl+R / Ctrl+Shift+R | Rotate pages right / left |
| Ctrl+D, Delete | Duplicate / delete selected pages (or the selected mark) |
| Ctrl++ / Ctrl+- / Ctrl+0 | Zoom in / out / fit page |
| Arrow keys (Shift for bigger steps) | Nudge the selected mark or signature |
- Conversion, PDF editing, OCR and the file utilities run on your PC. Foldex has no account, no telemetry and no online conversion service; OCR uses the text recognition engine built into Windows.
- Foldex connects to the internet only when you ask it to: to download an optional engine (from pinned addresses, checked against a SHA-256 hash), or when you choose Check for updates in About, which asks GitHub for the latest release. Links in the app open in your browser.
- Optional engines such as FFmpeg and LibreOffice run locally as separate programs inside Foldex's own folder.
- Saved signatures stay on your PC in
%APPDATA%\Foldex\signatures.
Some conversions need an optional engine download; text editing is line by line without paragraph reflow; scanned pages need OCR first; XFA forms aren't supported; one PDF is open at a time; the installer isn't code-signed yet; and Foldex runs on Windows only for now. The full list: docs/KNOWN_LIMITATIONS.md.
You need Windows 10/11 x64 and the .NET 10 SDK.
git clone https://github.com/ShinojJerald/Foldex.git
cd Foldex
dotnet build Filee.slnx -c Release
# Run without touching an installed Foldex's settings
$env:FILEE_DATA_DIR = "$env:TEMP\foldex-dev"; dotnet run --project src/Filee.App -c Release
# Tests
dotnet test tests/Filee.Engines.Tests -c Release
dotnet test tests/Filee.App.Tests -c Release
# Installer and portable ZIP → Releases\
.\build\build-installer.ps1 -PortableRunning from source uses the repository's engines\ folder, filled by build\fetch-engines.ps1. Project names still
start with Filee (the codebase Foldex grew from); the app, executable and installer are Foldex.
More: docs/BUILD_AND_INSTALL.md · docs/ARCHITECTURE.md ·
docs/ENGINES.md · docs/PDF_FEATURES.md ·
docs/ADDING-A-CONVERTER.md.
Foldex has about 1,580 automated tests, including tests that drive the app with simulated mouse and keyboard input and render saved PDFs to check them; see docs/TEST_RESULTS.md.
Bug reports, ideas and format requests are welcome in Issues. Please don't attach private documents; a small sample file that shows the problem helps most.
If Foldex saves you time, you can buy me a coffee or follow my work on GitHub.
Foldex is released under the MIT License.
- Built on Filee by Myeonggu Kim (KnifeLemon) and contributors, MIT License. Foldex keeps Filee's converter and adds the PDF workspace, Signature Studio, the file utilities and a new interface.
- Signature fonts (Great Vibes, Dancing Script, Pinyon Script, Kaushan Script, Sacramento) are under the SIL Open Font License 1.1; their licence texts are in src/Filee.App/Assets/Fonts/Signatures and are installed with the app.
- Other libraries and engines: THIRD-PARTY-NOTICES.md.