Handy tools.
Privacy-focused.
Every tool runs locally on this page. Each tool page carries a privacy ledger stating exactly what it touches. Works offline once visited.
Text
-
Case converter
Convert identifiers between snake_case, camelCase, PascalCase, kebab-case, UPPERCASE, lowercase and spaced words — every line, all at once.
-
Diff tool
Compare two texts line by line — side-by-side or unified view, intra-line highlighting, add/remove counts and a copyable unified diff.
-
Text counter
Live word, character, sentence, line, paragraph and byte counts — Unicode-correct for emoji and Japanese/Chinese — with reading-time estimates.
-
Text line tool
Sort (natural, locale-aware), deduplicate, reverse, shuffle, trim, number and prefix lines — operations compose in a visible order.
-
Markdown preview
A side-by-side Markdown editor and live preview with synced scrolling — CommonMark+GFM subset rendered locally, raw HTML kept inert.
-
Placeholder text
Lorem Ipsum by paragraphs, sentences or words — plain or HTML output, a Japanese filler mode, and a reproducible seed toggle.
-
Cut (fields & characters)
Extract fields or character ranges from each line, cut(1)-style — delimiters, 1,3,5-7 lists, complement, output delimiter, only-delimited.
-
Regex replace (sed-style)
sed s/// in the browser: replace only the matched part of each line with JS regex, $1/$
substitutions, per-line or whole-text, live before/after panes. -
HTML to text
Paste HTML and get readable plain text — tags stripped with structure kept, entities decoded, via a local tokenizer, never innerHTML.
-
Markdown table
Build GFM pipe tables in an editable grid — alignment, escaping handled — or paste a ragged table to prettify it. CSV/TSV import, HTML copy.
-
URL slug generator
Turn titles into URL-ready slugs live — ASCII transliteration or keep-Unicode for CJK, stop-word removal, length trim, batch mode.
Web
-
URL encoder
Encode and decode URL escapes — component or full-URI semantics — and break a pasted URL into scheme, host, path and decoded query parameters.
-
HTML entities
Encode text for safe HTML embedding and decode any entity soup back — named and numeric references, with a common-entities reference table.
-
Favicon generator
Drop an image and get the standard favicon set — favicon.ico, apple-touch-icon, 192/512 PNGs — plus ready-to-paste head and manifest snippets.
-
Meta tag generator
Fill a form and get the complete head block — title, description, canonical, Open Graph and Twitter Card — with length gauges and a share preview.
-
URL parser & builder
Break a URL into its parts, edit any of them — including a decoded query table — and watch the composed URL re-encode live.
-
HTML formatter
Beautify or minify HTML — indent width, wrap column, blank-line control; pre/textarea/script/style content never reflowed, never innerHTML.
Languages & formats
-
JSON formatter
Pretty-print, minify and validate JSON — selectable indent, sorted keys, and precise errors with line, column and a caret excerpt.
-
Regex tester
Test JavaScript regular expressions live — flags, match highlighting, numbered and named groups with indices, and a replace preview.
-
JWT decoder
Decode JWT header and payload with annotated claims and local expiry times — and verify HS256/384/512 signatures.
-
CSV ⇄ JSON
Convert CSV to JSON and back — RFC 4180 quoting, delimiter auto-detection, header and type-inference toggles, downloads both ways.
-
Template renderer
Render Nunjucks or Handlebars templates against JSON data, live — the engines ship in the bundle and the result stays inert text.
-
JSON diff
Compare two JSON documents structurally: added/removed/changed entries with paths, a marked merged tree, and RFC 6902 patch output.
-
YAML ⇄ JSON
Convert YAML to JSON and back — safe parsing (no custom tags), indent choice, block-style YAML, errors with line and column.
-
Base64 text & file
Encode and decode Base64 with correct UTF-8 both ways — URL-safe alphabet, padding toggle, tolerant decode, small files to and from Base64.
-
SQL formatter
Format SQL locally — dialect choice, indent width, keyword case, and a one-line minify mode. Text-only, nothing executes.
Date & time
-
Timestamp converter
Unix epoch to local, UTC, ISO 8601 and relative time — auto-detecting s/ms/µs — and dates back to epoch, with a live ticking now.
-
Cron schedule tool
Explain a cron expression in plain words, list its next 10 runs in your timezone or UTC, and break down every field — with validation.
-
Date calculator
Days between dates with a years/months/days breakdown, calendar-aware add/subtract, weekday counts and business days.
-
Timezone converter
See one wall-clock moment in many zones at once — DST-aware via your browser, offset and DST marker per row, ISO 8601 copy.
-
Timer
Countdown or alarm clock with 30-second to 10-minute presets and a finish sound you pick — generated in the browser, works offline.
Numbers & units
-
Base converter
Encode and decode Base64, Base64URL, Base32, hex or any base with your own alphabet — with a bytes view.
-
Unit converter
Length, mass, temperature, area, volume, speed, data size, pressure, energy and time — every unit of a category updates live, with exact factors.
-
chmod calculator
A rwx grid, octal and symbolic fields, all synchronized — edit any one and the others follow; paste an ls -l mode; presets with explanations.
-
Percentage calculator
Four sentence-style solvers: X% of Y, what percent X is of Y, percent change, and increase/decrease by a percent — live, localized numbers.
-
Aspect ratio calculator
Reduce W×H to its simplest ratio, lock it to solve either dimension, browse common ratios with typical resolutions, and fit/fill a box.
-
Resistor color code
Decode 4/5/6-band resistor colors to resistance, tolerance and temperature coefficient — or enter a value and get the bands back.
Color
-
Color converter
Any CSS color to hex, RGB, HSL, HWB and OKLCH at once — with an alpha swatch and a WCAG contrast checker with AA/AAA badges.
-
CSS gradient builder
Build linear, radial and conic gradients with reorderable color stops, alpha and position sliders, a live preview and modern-syntax CSS.
-
Color palette extractor
Drop an image and get its 5–10 dominant colors — median-cut on a downscaled canvas, hex/RGB per swatch, entirely local.
-
Contrast checker
WCAG 2.x contrast ratio for any color pair — AA/AAA matrix with the thresholds printed, live sample, nearest-passing suggestions, eyedropper.
Images & codes
-
QR code generator
Generate QR codes locally — error-correction and size controls, PNG and SVG downloads.
-
Image ⇄ Base64
Turn a local file into Base64, a data: URI and ready-to-paste CSS/
snippets — or decode Base64 back to a file, with previews.
-
Image resizer
Resize an image entirely in your browser — aspect lock, percent scaling, presets, PNG/JPEG/WebP with quality slider and size estimate.
-
EXIF viewer & remover
See what metadata your photo carries — camera, capture time, GPS with a privacy warning — parsed locally, and download a clean copy.
-
Barcode generator
Generate scannable Code 128 and EAN-13 barcodes locally — check digit handled, SVG and PNG download, spec-minimum quiet zones.
Network
-
Subnet calculator
IPv4 and IPv6 subnetting — network, broadcast, usable range, masks in every notation, type notes, a split view, and RFC 5952 canonical IPv6.
-
IPv6 address tool
Enter an IPv6 address in any valid form and get the RFC 5952 compressed and fully expanded forms, its type, and a special-address reference table.
Random & hashing
-
Password generator
Build passwords from character groups you fully control — position rules, counts, separators — with cryptographic randomness.
-
Hash generator
SHA-256, SHA-384, SHA-512 (and legacy SHA-1) of text or a local file — hex and Base64, with checksum verification.
-
UUID generator
Version 4 and timestamp-ordered version 7 UUIDs, up to 1000 at once — copy-all, .txt download, and an inspector that decodes version, variant and v7 timestamps.
-
Random picker
Pick winners without replacement, shuffle a list, or split it into balanced teams — crypto-grade randomness, session-only no-repeat memory.