Audio Converter
Convert audio files between formats and codecs entirely on your device using FFmpeg.
- Per-file format + codec controls
- Batch conversion with ZIP downloads
Documentation
Install
- Download the latest release.
- Windows: run offkit-<version>.exe. SmartScreen may show "Windows protected your PC" because the installer is not code-signed. Choose More info, then Run anyway. Open Offkit from the Start menu.
- macOS: open offkit-<version>-arm64.dmg (Apple Silicon) or offkit-<version>-x64.dmg (Intel) and drag Offkit to Applications. The app is ad hoc signed and not notarised, so on first launch right-click it and choose Open, or go to System Settings, then Privacy & Security, and choose Open Anyway.
- Linux: run offkit-<version>-x86_64.AppImage, or install offkit-<version>-amd64.deb.
Each release also lists SHA256SUMS.txt for checking your download.
The audio and video tools need FFmpeg and ffprobe installed, because Offkit does not bundle them. Use winget install Gyan.FFmpeg on Windows, brew install ffmpeg on macOS, or sudo apt install ffmpeg on Linux. Until then the app shows a Get FFmpeg screen. PDFium for the PDF tools is bundled.
The app does not update itself. To update, download the newest release and install it again. To uninstall on Windows, open Settings, then Apps, then Installed apps, find Offkit and choose Uninstall.
Privacy
Every tool works on files on your own device, in the browser and in the desktop app alike. Nothing is uploaded and there is no account.
Directory Scaffold is the one tool that goes online: it asks api.github.com for a repository's file list, and only when you run it. A GitHub token you give it for a private repository is kept in memory on that page only. It is never saved, and it is sent only to api.github.com.
This website counts page views with Vercel Web Analytics and reports script errors to Better Stack. Neither receives your files, and Better Stack's script does not load on the Directory Scaffold page. The desktop app makes no network requests of its own and sends no analytics or error reports. It only opens a link in your browser when you click one.
Tools
Audio
Audio Extractor
Extract the audio track from any video file and download it in your chosen format and codec.
- Video to audio extraction
- Codec-aware output selection
Audio Editor
Trim, adjust speed, shift pitch, and apply EQ to any audio file, all on your device.
- Waveform trim handles
- Speed, pitch & EQ controls
Audio Joiner
Drag-and-drop multiple audio files and join them into a single file in your chosen format.
- Drag-to-reorder tracks
- ffmpeg concat demuxer
Video
Video Converter
Convert videos between formats and codecs directly on your device using FFmpeg.
- Per-file video and audio codec mapping
- Batch conversion and ZIP export
Frames Extractor
Upload a GIF or video and extract every frame as individual PNG images, then download them as a ZIP.
- Frame thumbnail grid
- FPS and frame-count metadata
Video Editor
Trim, crop, rotate, resize, flip, adjust speed and volume for any video, entirely on your device.
- Trim, crop, rotate & resize
- Speed & volume adjustment
Video Merger
Drag-and-drop multiple video files, reorder them, and merge into a single video.
- Drag-to-reorder clips
- Resolution normalization
Dev
Directory Scaffold
Turn a folder or a public GitHub repo into an ASCII or Markdown tree.
- Collapsible file tree UI
- ASCII tree copy and TXT export
Archive Extractor
Upload a ZIP archive, preview its file tree, and extract individual files or download everything.
- Interactive file tree
- Extract individual files or all
Archiver
Drop files to create a ZIP archive instantly on your device.
- Editable file paths
- DEFLATE compression
Images
Image Cropper
Crop one or many images on your device - apply individual crops per image or a single crop to all at once.
- Individual and batch crop modes
- Canvas drag-resize crop handles
Image Converter
Convert popular image formats locally with batch downloads, quality controls, and upload guardrails.
- Batch conversion with ZIP downloads
SVG
SVG Border Animator
Upload any SVG and animate each path border locally with stroke-dashoffset controls and export-ready output.
- Sequential or simultaneous path animation
- Downloadable SVG with embedded keyframes
SVG Pattern Generator
Create beautiful, scalable vector patterns directly on your device. Export native CSS backgrounds or raw SVG data URIs instantly.
- Injected vector properties directly generated
- CSS backgrounds
SVG Optimizer
Clean up messy SVGs, strip metadata, dial in decimal precision, and convert to JSX directly on your device.
- Live visual preview with JSX conversion
Colors
Gradient Maker
Build multi-stop gradients with live previews, PNG exports, CSS output, and Tailwind arbitrary values.
- Drag and reorder gradient stops
Gradient Library
Browse curated named gradients and copy them as CSS or Tailwind-ready arbitrary values.
- Curated presets with instant PNG downloads
Palette Library
Explore curated color palettes, copy individual swatches, or export full palettes as JSON.
- Copy any swatch or full palette JSON
Palette Extractor
Upload an image and extract its dominant colors into a copyable palette, computed locally on your device.
- On-device dominant color extraction
Gradient Converter
Convert CSS gradients into Tailwind arbitrary values or switch between linear, radial, and conic syntax.
- Live preview while converting gradient syntax
Color Converter
Convert HEX, RGB, HSL, HSV, OKLCH, and named colors into every other format at once.
- All major color models at the same time
CSS
CSS Blob Generator
Create intricate, organic shapes natively by independently customizing the 8 anchor points of the border-radius property.
- 8-Point interpolators natively computed
Glassmorphism Generator
Design stunning frosted-glass UI elements with real-time backdrop filtering and export the CSS directly.
- Interactive refractive blur previews
- Tailwind & CSS
Box Shadow Generator
Create layered CSS shadows natively through visual controls and export the exact styling string for your projects.
- Detailed multi-layer controls natively
PDF Toolkit
Merge multiple files, break PDFs apart by page, reorder structure, or compress files directly on your device.
- Compress documents securely natively
PDF ↔ Image Converter
Merge images into a single PDF, batch convert them, or extract pages from existing PDFs as images.
- Drag-to-reorder combined page layout
PDF Merger
Combine multiple PDF documents into one file with drag-to-reorder.
- Drag-to-reorder pages
- Per-file page count
PDF Splitter
Break a PDF into individual pages or extract specific page ranges.
- Visual page picker
- Fixed-size chunk splitting
PDF Compressor
Reduce PDF file size by rasterizing pages at adjustable quality and resolution.
- Adjustable render scale & quality
- Size comparison preview
Convert to PDF
Convert images to PDF. Drop multiple images and combine them into a single document.
- Drag-to-reorder images
- Fit, A4, or Letter page sizes
Convert from PDF
Extract PDF pages as PNG or JPEG images and download them as a ZIP.
- Configurable render scale
- PNG & JPEG output
Text
Lorem Generator
Generate customized placeholder text instantly for your mockups, using either classic Latin or random English prose.
- Configurable words, sentences, and paragraphs
Diff Checker
Find inline character-level or line-level text differences with robust ignoring whitespace and case sensitivity.
- Unified patch and raw markup generation
JSON Formatter
Pretty-print, minify, validate, and copy JSON on your device.
- Pretty print or minify in one click
Base64
Encode and decode text with a clean local workflow that stays entirely on your device.
- Unicode-safe encode and decode
Markdown Editor
Write Markdown with a live split-pane preview, toolbar shortcuts, and export to .md or PDF.
- Live split-pane preview
- Toolbar shortcuts & PDF export
Known limits
- In the browser, video can be encoded as H.264, MPEG-4, VP8, ProRes, FLV and Theora; H.265 and VP9 are not in its FFmpeg build. The desktop app offers whatever encoders the FFmpeg you installed has.
- In the browser, media tools hold the whole file in memory, so very large videos can fail. Try a shorter clip or a smaller file.