Blog & Guides
Notes on file formats and on what conversion actually does to a file — written while building the tools on this site, mostly because the answer turned out to be more interesting than expected.
A recurring theme: the format in a filename is rarely the thing that matters. A MOV that will not play on Windows is almost never a container problem, splitting a PDF makes the pages add up to several times the original, and pulling an MP3 out of a video is a second round of lossy compression rather than an extraction. Most of these posts exist because a plausible-sounding assumption turned out to be wrong.
Where a post gives a number — a byte count, a bitrate, a resolution — it was measured against the code running on this site rather than recalled from documentation, and the settings it names are the ones the tool actually uses. Where a tool cannot do something, the post says so; several of them end by recommending you keep the original file.
A Convertio Alternative That Converts Files Locally
Convert images, video, audio, and data files without uploading them to Convertio's servers. A free, private alternative that runs entirely in your browser.
An iLovePDF Alternative That Never Uploads Your Files
Merge, split, and convert PDFs without sending them to iLovePDF's servers. A free, offline-capable alternative that processes everything on your device.
The Best Smallpdf Alternative for Private PDF Editing
Merge, split, and compress PDFs without uploading them to Smallpdf's servers. A free, private, browser-based alternative that never sees your files.
How to Open RAR Files Online Without WinRAR
Learn what RAR files are, why your computer can't open them by default, and how to extract one online without installing WinRAR or 7-Zip.
What is a DOCX file? A guide to the Word format
Learn what makes up a DOCX file, why it replaced the old .doc format, and how to convert Word documents into portable HTML or Markdown.
What is an MKV file? A guide to the Matroska video format
Learn what MKV (Matroska) video files are, why they hold multiple audio and subtitle tracks, why some devices refuse to play them, and how to convert MKV to MP4.
Why Browser-Based WASM Converters Are the Future
Explore why WebAssembly (WASM) is replacing cloud servers for file conversion, offering unparalleled privacy, speed, and security.
Base64 Encode & Decode Safely in Your Browser
Encode text to Base64 or decode Base64 strings. 100% private, free, and secure client-side processing with full UTF-8 support.
URL Encoder & Decoder - Secure Offline Tool
Easily encode text for URLs or decode URL-encoded strings. 100% private, free, and secure client-side processing.
Split PDF Files Free & Offline - The Private Solution
How splitting a PDF actually works, why the resulting files add up to more than the original, and what a page copy silently leaves behind.
Compress PNG Offline - A Private TinyPNG Alternative
Learn how to dramatically reduce the file size of your PNG and JPG images directly in your browser without uploading them to a server.
Extract ZIP Files Online Privately - No Server Uploads
Unzip your archives securely in your browser. Our tool extracts ZIP files completely offline to ensure maximum privacy for sensitive data.
How to Open HEIC Files on Windows
Learn the easiest ways to view HEIC files on a Windows PC without installing sketchy third-party software.
Image to PDF Converter - Secure, Fast, & Local
Convert JPG, PNG, and WebP images to PDF documents directly in your browser. No server uploads, total privacy, and instant results.
JSON to XML Converter - Free Local Developer Tool
Convert JSON to XML or XML to JSON instantly inside your browser. Fast, free, and completely offline with zero server uploads.
JSON to YAML Converter - Developer Friendly & Local
Instantly convert JSON objects to YAML (and vice-versa) entirely offline in your browser. Perfect for DevOps, Kubernetes, and configuration files.
Lossless PNG Compression: A Private TinyPNG Alternative
Learn how to reduce PNG file sizes by up to 30% without losing a single pixel of quality, using our completely offline and private image compressor.
Merge PDF Files Free & Offline - The Private Solution
Learn how to combine multiple PDF documents into a single file directly in your browser without uploading sensitive data to cloud servers.
MOV to MP4 Converter - Free, Fast, No Server Upload
MOV and MP4 are closer relatives than they look. What actually makes an iPhone video unplayable on Windows, and what this converter does about it.
Optimize SVG Files Locally - Fast & Free Tool
Minify SVG graphics and remove unnecessary paths using SVGO natively in your browser. Dramatically improve SEO and reduce image load times.
PDF to JPG/PNG Converter - Free Local Image Extraction
What resolution a PDF page renders at, why PNG usually beats JPG for text documents, and what you permanently lose by turning a PDF into pictures.
PNG to ICO Converter - Free & Local Icon Generator
Convert PNG images to ICO format for favicons instantly in your browser. 100% private, no server uploads, and completely free.
Convert GPS Data (KML & GPX) to GeoJSON for Web Apps
A comprehensive guide for web developers on transforming complex XML-based GPS data formats like KML and GPX into developer-friendly GeoJSON arrays.
CSV to JSON: Automating Data Transformation for Apps
A developer guide on safely converting Comma-Separated Values (CSV) spreadsheets into JavaScript Object Notation (JSON) array structures.
How to Safely Extract Audio from Video (MP4 to MP3)
Pulling an MP3 out of an MP4 is a lossy-to-lossy transcode, and choosing WAV instead does not undo it. What the extraction really does to your audio.
WebP vs AVIF: Which Next-Gen Image Format is Better?
A detailed comparison of WebP and AVIF image formats, their compression capabilities, browser support, and which one you should use for SEO.
What is an AVIF file and why should you use it?
Learn about the AVIF image format, its benefits over JPEG and PNG, and how to start converting your images to AVIF for better web performance.