Why this section exists
Every tool on tool80.com runs in your browser, so your files never leave your device. But a tool is only half the story: knowing when to compress an image, how a QR code stores your WiFi password, or why a long passphrase beats a short complex one is what actually helps you get the job done. This column is where we write that down.
We publish practical guides that pair with the tools — short, specific, and written to be read in a couple of minutes. New guides are added as we write them, and we take topic suggestions from readers on the Contact page.
What we're writing about
These are the first guides in progress. Each one is built around a real question people ask before they open the matching tool:
Sharing WiFi without giving away the password
How a QR code lets guests join your network safely, what the encoded string actually contains, and when you should still type the password by hand.
NewImage compression: when lossy is good enough
JPG vs PNG vs WebP, what "quality" really controls, and how to shrink a photo for the web without anyone noticing the difference.
NewWhat makes a password strong (and why length wins)
A plain explanation of entropy, why a long passphrase beats "P@ssw0rd!", and how the Password Generator turns that into something you can use.
NewReading QR codes: what's inside the square
How the QR decoder turns a picture back into text, the kinds of data a code can carry (URL, WiFi, contact), and why some scans fail.
NewSmall tools, small friction: where they show up
The everyday moments a tiny utility saves you — from a bill split abroad to a timezone mix-up — and why a drawer of free, local, no-signup tools is the point of this site.
NewIn the AI age, how to actually use AI well
A blunt take: AI is a fast junior assistant, not a brain. What to hand it, what to keep for yourself, and why the small tools still matter once the model is done.
NewText to speech: the quiet tool for catching your own mistakes
Why listening to your own writing is the best proofread you'll do all day, when to use local read vs a downloadable MP3, and how the reader handles your text.
NewLanguage shouldn't be a border: a toolbox for anyone, anywhere
The internet reached everywhere, but most tools still assume one language and one account. Why a free, local, no-signup toolbox helps someone in any country do the small things faster.
NewFree PDF tools that run in your browser
Merge, split, compress and convert PDFs without uploading a thing — a plain-English guide to the Docs tools, and why local processing keeps your files private.
NewRemove a background in your browser: a step-by-step guide
How tool80.com's free in-browser AI background remover works — cut out a photo, swap in a new background, and why your image never leaves your device.
NewMeet the free online photo editor: Photoshop-style editing in your browser
An introduction to tool80.com's full-featured free photo editor — open PSD, XCF, Sketch and RAW, edit with layers, masks and filters, no install, no sign-up.
NewCrop a photo to exact dimensions online — no software, no upload
A plain guide to cropping a photo to precise pixels in your browser: set a custom aspect ratio, keep it private, and download without installing anything.
NewRotate and flip an image, or straighten a crooked scan — free and private
How to rotate a photo 90/180 degrees, flip it horizontally or vertically, and fix a tilted scan, all in your browser with no upload.
NewConvert JPG to PNG to WebP online — free, no quality surprise
A plain guide to converting between JPG, PNG and WebP in your browser: when each format wins, and how to avoid silently losing quality or transparency.
NewAdd a watermark to photos in bulk — free and private
How to stamp a text or logo watermark onto one or many photos at once, set position, size and opacity, all in your browser with no upload.
NewSplit one image into 9 tiles for an Instagram grid (九宫格) — free
How to cut a single picture into a 3x3 (or any NxN) grid for an Instagram 九宫格 post, in your browser, with no upload and a downloadable ZIP.
NewRotate PDF pages and save — free, no upload
How to rotate one, several, or all pages of a PDF 90/180/270 degrees in your browser and download the fixed file, with no upload.
NewAdd a watermark to a PDF online — text or brand, free and private
How to stamp a text or image watermark across PDF pages in your browser: position, size, opacity and angle, with no upload of your document.
NewJWTs explained: how to read, verify and create a token (HS256)
A beginner-friendly explainer of JSON Web Tokens — what the three parts mean, how to decode and verify a JWT with HS256, and how to create one, all in your browser.
NewCron syntax explained with examples — read any cron schedule
A plain walkthrough of the 5-field cron format with real examples, plus how to preview the next run times of a schedule, all in your browser.
NewExtract emails, phone numbers and URLs from text in bulk
How to pull every email, phone number and link out of a block of text at once, deduplicated and ready to copy or download — all in your browser.
NewHow to write meta tags for SEO (with a live preview)
A practical guide to title tags and meta descriptions: length, structure, and how they look in Google — plus a free tool to preview and generate the code.
NewHow to create a robots.txt file (with examples)
A plain guide to writing a robots.txt: allow or block crawlers, set crawl-delay, and point to your sitemap — plus a free generator that builds and downloads the file.
NewSuggest a topic
Don't see the guide you need? Tell us on the Contact page and we'll add it to the list.