Guides
Short, practical how-tos for the file and device tasks people search for most. Each guide explains the why in plain words and links to a free tool that does the job in your browser.
Privacy & security
How to Encrypt a File With a Password
Protect a document before emailing or storing it in the cloud. What strong file encryption looks like, how to choose a password, and how to do it in your browser.
How to Remove EXIF and GPS Location Data From Photos
Photos can reveal where they were taken, when, and with which device. Here's how to check what's hidden in an image and remove it before sharing.
How to Verify a File Checksum (SHA-256)
Download pages often list a SHA-256 hash. Here's what it proves, how to compute one on Windows, macOS, Linux or in the browser, and how to compare the result.
Audio & video
How to Compress a Video for Email or Discord
Hit a file size limit exactly by choosing the right bitrate and resolution. The math behind it, current limits, and how to compress in your browser without uploading.
How to Convert MP4 to MP3 (and When to Keep M4A)
Extract the audio from a video file as MP3 without uploading it. Which bitrate to choose, how to cut a section, and why M4A is sometimes the better choice.
Code & data
How to Open a JSON File and Find Syntax Errors
A JSON file won't load and the error only says "unexpected token". Learn how to open JSON readably and track down the exact line that breaks it.
What Is a JWT and How Do You Decode It?
JSON Web Tokens explained - the three parts, the common claims, what "signed" does and doesn't mean, and how to decode and verify a token safely.
Design & accessibility
How to Check Color Contrast for Accessibility (WCAG)
What contrast ratio text and buttons need under WCAG, how the ratio is calculated, and how to fix colors that fail without changing your design's character.
How to Make a Favicon (Sizes, Formats and HTML)
Which favicon files a modern website actually needs, how to create them from text, an emoji or a logo, and the exact HTML to add.
How to Merge PDF Files Without Uploading Them
Combine several PDFs into one document on your own device. Here's how to merge, reorder pages and keep private files private.
How to Reduce PDF File Size Without Losing Readability
Most oversized PDFs are big because of images. Learn what actually takes up the space, and how to shrink a PDF for email or upload forms.