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Practical guides written for this site: the reasoning behind the tools, with real numbers, worked examples and the relevant tool linked at the end of every piece. 30 articles and counting.
Strength meters look scientific, but most are estimating one simple quantity: how many guesses an attacker would need. Here is the arithmetic behind the bars, why two meters disagree about the same password, and what the colours never tell you.
A passphrase trades symbol soup for length: several ordinary words chosen at random. This guide covers the wordlist maths, why the words must be chosen by dice or software rather than by you, and how to handle separators, capitals and sites that insist on a digit.
A checksum lets you prove a file arrived exactly as its publisher sent it — byte for byte. This walkthrough explains what you are actually comparing, how to do it on any system, and the one situation where a matching checksum still proves nothing.
A UUID is 128 bits with a version number hidden in the middle. Version 4 is random, version 7 is time-ordered, version 5 is a hash of a name — and picking the wrong one has real consequences for databases and privacy. A field guide to all five, plus the new trio.
Three famous hash functions, three different eras of cryptographic confidence. This comparison covers output sizes, what "broken" actually means for each one, and the jobs each can still legitimately do — including the one job none of them should ever do.
Four formats, four different bargains with quality, size and compatibility. This comparison explains what each format actually does to your pixels, where the commonly quoted savings come from, and how to pick per image instead of by habit.
"Lossy" does not have to mean "looks worse". This guide explains where lossy compression hides its damage, how to choose a quality setting with your eyes instead of a superstition, and the two-pass workflow that keeps photos crisp at a fraction of their camera size.
The most expensive image mistake on the web is also the simplest: uploading a 4000-pixel photo into a 700-pixel slot. This guide covers how to work out the sizes you actually need, how srcset lets browsers pick, and why oversized images sabotage your LCP score.
The 16×16 icon in a browser tab is asked to do a surprising amount of work — tabs, bookmarks, home screens, search results, dark mode. This checklist covers which sizes and formats you actually need now, how to design artwork that survives being tiny, and the markup that ties it together.
You do not need an art degree to use colour well on screen — you need three ideas: hue, saturation and lightness; an honest map of how RGB, HSL and OKLCH describe them; and the wheel relationships that make palettes feel deliberate. This is the working minimum, with numbers.
4.5:1, 3:1, 7:1 — where those numbers come from, how the ratio is calculated from two hex codes, what counts as "large text", and how to fix a failing pair without surrendering your brand colour. The whole standard, in working terms.
One brand colour is not a palette, but it is enough to build one: a lightness ramp for surfaces and text, a disciplined supporting cast, neutrals with a hint of the brand in them, and semantic colours that pass contrast. A step-by-step construction you can reuse for any starting hue.
Gradients are easy to write and surprisingly easy to get wrong: muddy midpoints, visible banding, text that fails contrast at one end. This guide covers the three gradient types, colour-stop craft, interpolation in OKLCH, and the performance and accessibility rules that separate polish from decoration.
JSON parsers fail with unhelpful messages at exact positions. This field guide maps the errors you will actually meet — trailing commas, single quotes, unquoted keys, comments, encoding traps — to their causes and fixes, and shows how to hunt an error down when the message will not tell you plainly.
JSON is a tree; CSV is a grid. Squeezing one into the other forces decisions — about nested objects, missing keys, commas inside text — that naive converters make silently and wrongly. This guide names each decision so you can make it deliberately and check the result.
Base64 turns any bytes into text from a 64-character alphabet so binary data can travel through text-only channels. This explainer walks the encoding by hand, explains the 33% size tax and the padding equals signs, and settles the most dangerous misconception about it.
A URL can only contain a small, safe set of characters, so everything else must be percent-encoded — but the rules change between the path, the query and form submissions. This guide maps the territory: which characters are reserved, when a space is + and when it is %20, and how UTF-8 does the heavy lifting underneath.
Diff tools feel like magic — paste two versions, watch the changes light up. Underneath sits one elegant algorithm problem: finding the longest sequence two texts share. This explainer covers line diffs, word refinement, the Myers algorithm in plain terms, and how to read (and export) the output.
Is "1,200" one word or two? Does a hyphenated compound count once? Word counts are conventions, not measurements, and different tools apply different conventions. This guide states the common rules, shows where counters diverge, and tells you how to hit a limit safely when the counter is not yours.
Every identifier, URL and headline wears a case style, and each community has strong opinions about which. This field guide defines the eleven styles you will actually meet, shows how acronyms and numbers strain them, and matches styles to the places they are conventional — so you can convert confidently instead of guessing.
The world's most famous nonsense has a real source — a Cicero text on ethics, scrambled by a Renaissance printer. This article traces Lorem Ipsum from 45 BC to your design tool, explains why placeholder text both helps and lies, and lays out the modern alternatives by situation.
Math.random() looks random and is not safe; crypto.getRandomValues() is drawn from your operating system's entropy and is. This article explains the difference in plain language, the rejection-sampling trick good generators use, and how to sanity-check any tool that claims to be random.
Transparency is a fourth channel of data riding beside red, green and blue — and each format treats it differently. This guide explains alpha values, premultiplication and edge halos, why JPEG deletes transparency, and how to keep cut-outs clean across backgrounds.
Dark mode is not an invert button. Done well, it is a second, parallel design pass: near-black surfaces with a lightness ladder, desaturated accents, contrast measured against real backgrounds, and shadows replaced by light. This guide is the complete method.
Nobody can memorise a hundred strong, unique passwords — and nobody needs to. This guide explains the one-master-password model, how to migrate from reused passwords without drowning, and the settings (length, 2FA, recovery) that decide whether a manager makes you safer or just differently vulnerable.
About 1 in 12 men and 1 in 200 women have colour-vision deficiency, most of it red-green. This guide explains the types in perception terms, why "never use colour alone" is the rule that does the work, and how to choose palettes that stay distinguishable — with simulators as checkers, not designers.
CSV looks too simple to go wrong, which is exactly how it goes wrong: shifted columns from an unquoted comma, dates reinterpreted by locale, IDs mangled into scientific notation. This guide states the actual quoting standard, the delimiter politics, and the defensive moves for files that must survive Excel.
The letter ü is one character, two UTF-8 bytes, six URL characters (%C3%BC) and four Base64 characters (w7w=) — all the same text. This article explains the character/byte distinction underneath all three, and why most 'encoding bugs' are really one missing UTF-8 step.
A privacy policy is a promise; an architecture is a fact. This article explains the technical difference between tools that upload your files to a server and tools that process everything in your browser — and how to verify, yourself, in under a minute, which kind you are using.
Most image problems on published pages were preventable in the five minutes before upload. This checklist runs the whole gauntlet — dimensions, format, compression, transparency, metadata, naming, alt text and delivery markup — in the order that catches expensive mistakes while they are still cheap.