Original long-form guides on developer tools, privacy, and browser-first web utilities.https://zeroutil.com/en-ushttps://zeroutil.com/blog/aes-gcm-vs-cbc/https://zeroutil.com/blog/aes-gcm-vs-cbc/What block cipher modes do, why GCM has mostly replaced CBC for new code, the IV and authentication rules that matter, and where each mode still earns its place.Sun, 26 Apr 2026 00:00:00 GMTaesencryptioncryptographygcmcbchttps://zeroutil.com/blog/flesch-kincaid-explained/https://zeroutil.com/blog/flesch-kincaid-explained/How the Flesch Reading Ease and Flesch-Kincaid Grade Level scores are computed, what they're good for, and the limits worth knowing before you optimize for them.Sun, 26 Apr 2026 00:00:00 GMTreadabilityflesch-kincaidwritingseoplain-languagehttps://zeroutil.com/blog/sale-discount-math/https://zeroutil.com/blog/sale-discount-math/The math behind percent off, stacked discounts, sales tax order, and the tricks retailers use to make a discount look bigger than it is.Sun, 26 Apr 2026 00:00:00 GMTdiscountpercent-offretail-mathsales-taxpersonal-financehttps://zeroutil.com/blog/sleep-cycles-90-minute-rule/https://zeroutil.com/blog/sleep-cycles-90-minute-rule/How sleep cycles really work, why the 90-minute rule is a useful approximation, and how to time bedtime so you wake up between cycles instead of mid-cycle.Sun, 26 Apr 2026 00:00:00 GMTsleepcircadianremproductivityhealthhttps://zeroutil.com/blog/us-tax-brackets-2024/https://zeroutil.com/blog/us-tax-brackets-2024/Marginal vs effective tax rates, how the brackets stack, what your 'tax bracket' actually means, and the worked example most people get wrong.Sun, 26 Apr 2026 00:00:00 GMTtaxesirsbracketspersonal-financemarginal-ratehttps://zeroutil.com/blog/developer-json-guide/https://zeroutil.com/blog/developer-json-guide/A comprehensive guide to JSON — the spec, the variants, the tooling, debugging, JWT and Base64 context, and how to ship systems that don't break on malformed payloads.Mon, 20 Apr 2026 00:00:00 GMTjsondevelopersguidejwtbase64debugginghttps://zeroutil.com/blog/online-privacy-guide/https://zeroutil.com/blog/online-privacy-guide/A comprehensive guide to online privacy in 2026 — threat models, browser-based vs. cloud tools, passwords, encryption, and the habits that matter most.Sat, 18 Apr 2026 00:00:00 GMTprivacysecuritybrowserencryptionpasswordsopsechttps://zeroutil.com/blog/qr-codes-explained/https://zeroutil.com/blog/qr-codes-explained/What the squares mean, how error correction works, when to use which encoding mode, and why your printed QR code sometimes doesn't scan.Fri, 17 Apr 2026 00:00:00 GMTqr-codeencodingerror-correctionprintinghttps://zeroutil.com/blog/unix-timestamps-timezones/https://zeroutil.com/blog/unix-timestamps-timezones/A practical walkthrough of Unix time, timezones, daylight saving time, and the handful of patterns that keep teams from shipping date bugs to production.Wed, 15 Apr 2026 00:00:00 GMTtimestampstimezonesdatetimedstiso-8601https://zeroutil.com/blog/compound-interest-intuition/https://zeroutil.com/blog/compound-interest-intuition/The math behind compound interest, why the Rule of 72 works, and why time matters more than rate for most real financial decisions.Mon, 13 Apr 2026 00:00:00 GMTcompound-interestinvestingmathfinancerule-of-72https://zeroutil.com/blog/password-strength-2026/https://zeroutil.com/blog/password-strength-2026/A practical look at entropy, NIST's current guidance, real GPU cracking speeds in 2026, and why passphrases beat forced complexity every time.Sat, 11 Apr 2026 00:00:00 GMTpasswordsentropysecuritypassword-managershttps://zeroutil.com/blog/never-paste-sensitive-data/https://zeroutil.com/blog/never-paste-sensitive-data/A practical threat model for developers and knowledge workers who use web tools at work. What's actually safe, what isn't, and what to do instead.Wed, 08 Apr 2026 00:00:00 GMTprivacyopsecsecretsincident-responsehttps://zeroutil.com/blog/base64-explained/https://zeroutil.com/blog/base64-explained/A practical walkthrough of Base64 encoding — what it actually does to your bytes, why it's not encryption, and the handful of real places it still earns its keep in 2026.Sun, 05 Apr 2026 00:00:00 GMTbase64encodingdata-urlsbinaryhttps://zeroutil.com/blog/jwt-authentication-mistakes/https://zeroutil.com/blog/jwt-authentication-mistakes/A tour of the JWT pitfalls that still ship to production in 2026 — algorithm confusion, weak secrets, missing expiry, and the subtle ways a library can fail open.Fri, 03 Apr 2026 00:00:00 GMTjwtauthenticationsecuritytokenshmachttps://zeroutil.com/blog/browser-pdf-tools-privacy/https://zeroutil.com/blog/browser-pdf-tools-privacy/What actually leaks when you upload a PDF to a random online tool, what modern in-browser PDF libraries can genuinely do, and a checklist for before you upload anything sensitive.Wed, 01 Apr 2026 00:00:00 GMTpdfprivacypdf-libbrowser-processinghttps://zeroutil.com/blog/debug-malformed-json/https://zeroutil.com/blog/debug-malformed-json/Every JSON parse error has a real cause hiding behind an unhelpful message. A practical guide to the five failure modes that produce 90% of the pain.Mon, 30 Mar 2026 00:00:00 GMTjsondebuggingparsersregexdiffhttps://zeroutil.com/blog/client-side-image-compression/https://zeroutil.com/blog/client-side-image-compression/How browsers compress images without touching a server — the real pipeline behind Canvas, OffscreenCanvas, and WebCodecs, and when it's not enough.Sat, 28 Mar 2026 00:00:00 GMTimage-compressionprivacybrowser-apisperformancehttps://zeroutil.com/blog/json-vs-json5-vs-jsonc/https://zeroutil.com/blog/json-vs-json5-vs-jsonc/Three formats that look nearly identical, behave completely differently, and produce a steady stream of parser errors when confused. A practical guide to telling them apart.Wed, 25 Mar 2026 00:00:00 GMTjsonjson5jsoncparsersconfigurationhttps://zeroutil.com/blog/percentages-common-mistakes/https://zeroutil.com/blog/percentages-common-mistakes/Percentage points vs. percent, symmetric vs. asymmetric changes, markup vs. margin, and the other places where percentage math quietly lies.Sun, 22 Mar 2026 00:00:00 GMTpercentagesmathfinancebasicsstatisticshttps://zeroutil.com/blog/character-limits-social-2026/https://zeroutil.com/blog/character-limits-social-2026/Current character limits for X, Bluesky, LinkedIn, Instagram, Threads, Mastodon, and TikTok — and how each counts emoji, URLs, and multibyte characters differently.Wed, 18 Mar 2026 00:00:00 GMTsocial-mediacharacter-counttwitterlinkedinblueskyhttps://zeroutil.com/blog/what-counts-as-a-word/https://zeroutil.com/blog/what-counts-as-a-word/Word counts vary by tool because 'word' isn't a well-defined unit. A practical look at whitespace splitting, Unicode, hyphens, emoji, and the counting edge cases.Sun, 15 Mar 2026 00:00:00 GMTword-countunicodetext-processingtypography