INSTRUMENTS
A hundred tools that run in your browser
Work throws up small jobs: convert a format, hash a file, look inside a JWT. There are plenty of sites for that, but nobody can tell you whether what you paste is kept — and it is often your company’s data.
So these are mine. Everything computes in this tab: no upload, no connection, no logging. After the page loads it makes no further network requests, which is asserted by a test that blocks the deploy if it fails. Open the Network panel and check. It also installs for offline use.
100 / 100
A
A01Text statsCharacters, words, lines, paragraphs and reading time, counted separately for CJK and Latin.A02Case & namingcamelCase, snake_case, kebab-case, PascalCase, CONSTANT_CASE and title case, all at once.A03Line toolsSort, dedupe, reverse, number and affix lines — natural sort and case-insensitive options.A04Find & replaceLiteral or regex replace with capture groups and multiline mode, matches highlighted live.A05Text diffLine or word level diff of two texts. Hand-written Myers algorithm, nothing leaves the page.A06CJK typographySpacing between CJK and Latin, width normalisation, punctuation and curly quotes.A07WhitespaceTabs to spaces and back, trailing whitespace, blank-line squeezing, indent width.A08SlugifyTitles into URL slugs, with options for non-ASCII, separator and length cap.A09Fake dataNames, addresses, phones, emails, UUIDs, Luhn-valid test card numbers and filler text.A10Redact PIIsecretMask ID numbers, card numbers, phones, emails, IPs and long tokens before you paste a log.Text
Count it, sort it, compare it, clean it.
B
B01Base64Base64 for text and files, with URL-safe variant and Data URI output.B02URL codecPercent-encoding both ways, plus a table editor for query strings.B03HTML entitiesNamed and numeric entities both ways — minimal set or every non-ASCII character.B04Unicode escape\uXXXX, \xNN, \u{...} and a code-point inspector for when one character is the problem.B05BaseXHex, Base32, Base58, Base64url and raw byte arrays, all interchangeable.B06Line endingsCRLF/LF conversion, BOM detection, UTF-8 validation and invisible-character flagging.B07String escapeTurn text into a string literal you can paste into JSON, Java, C, Python, shell or SQL.B08Morse & NATOMorse code both ways, plus the NATO spelling alphabet for reading codes over the phone.B09Letter shiftROT13, arbitrary Caesar shifts and Atbash. This obscures text; it does not encrypt it.B10Hex viewerHexdump any file with an ASCII gutter and magic-number detection, streamed in a Worker.Encoding
Moving between ways of writing the same bytes.
C
C01JSON formatPretty-print, minify, sort keys and validate — syntax errors pinned to line, column and offset.C02Format convertJSON, YAML, TOML, XML, CSV and query strings. YAML/TOML cover a documented common subset.C03JSON queryPull fields out of a large JSON payload with path syntax. Hand-written evaluator, no eval.C04JSON to typesGenerate a TypeScript interface, Zod schema, Go struct or Pydantic model from a JSON sample.C05JSON diffStructural comparison — added, removed, retyped and changed listed apart. Not a text diff.C06CSV viewerPaste or drop CSV/TSV, then sort, pick columns, transpose, dedupe and summarise. Worker-backed.C07SQL formatBreak a one-line query into readable indentation, with keyword casing options.C08SQL ↔ dataBuild INSERT statements from CSV/JSON, or parse pasted INSERTs back into a table.C09.env convertsecret.env to JSON, YAML, compose environment or shell exports, with quoting handled.C10curl to codesecretTurn a curl command into fetch, axios, Python requests or httpie. Parsed, never executed.Data formats
JSON and its neighbours — validate, query, convert, type.
D
D01Regex testerLive matches and capture groups, run in a Worker with a timeout so backtracking cannot hang the page.D02Cron explainPlain-language reading of a cron string plus the next runs. Five-field and Quartz six-field.D03JWT inspectsecretDecode header and payload, flag expiry, and verify an HMAC signature with your own key, locally.D04ID generatorBatch UUID v4/v7, ULID and NanoID, plus decoding an existing ID back to version and timestamp.D05TimestampUnix seconds, millis and micros against ISO 8601 and RFC 2822, local and UTC side by side.D06BitwiseAND, OR, XOR, shifts and masks shown bit by bit, plus IEEE 754 float breakdown.D07SemverCompare and sort versions, and see exactly which versions a ^ ~ >= range covers.D08Commit messageA Conventional Commits form with breaking-change markers and subject-length checks.D09HTTP referenceSearchable offline reference for status codes, headers and cache directives.D10Tree drawTurn an indented list into a ├── └── tree you can paste into a README or an issue.Developer
The tabs that stay open all day.
E
E01Password generatorsecretSampled from crypto.getRandomValues without modulo bias, with the entropy in bits shown.E02PassphrasesecretMulti-word passphrases — easier to type than random strings. Entropy from the real wordlist size.E03Password strengthsecretEntropy estimate, common-password and keyboard-run checks, and the usual letter substitutions.E04HashSHA-256/384/512 plus SHA-1 and MD5 for text and files — the last two flagged as checksum-only.E05HMACsecretHMAC-SHA256/384/512 with your key — handy when debugging a webhook signature.E06Checksum verifyDrop a downloaded file, paste the published checksum, get a yes or no.E07AES encryptsecretAES-256-GCM for text and files. Keys from PBKDF2-SHA256 at 600,000 iterations, fresh salt and IV.E08Key pairsecretRSA or ECDSA key pairs from WebCrypto, exported as PEM and JWK. The private key never leaves the tab.E09TOTPsecretSix-digit codes computed locally from a secret, with the seconds remaining. Nothing is stored.E10Certificate inspectSubject, issuer, validity and SANs from a PEM certificate, plus SSH public-key fingerprints.Crypto
Randomness from getRandomValues, primitives from WebCrypto. Nothing hand-rolled.
F
F01Time zonesOne moment across several cities, with date rollover and DST flags, from the browser tz data.F02Working daysWorking days between two dates, or N working days out. The holiday table is editable.F03ROC date & weekROC year, Gregorian, ISO week number and ordinal day, all interchangeable.F04Age & anniversaryExact age, days to the next birthday, and the span between any two dates.F05Countdown & stopwatchCountdown and stopwatch with laps. It notifies when done and keeps time in a background tab.F06PomodoroWork and break cycles with adjustable lengths. The tally stays on this device. Works offline.F07Meeting slotsOverlay several time zones and working hours to see which hours everyone is awake.F08Shift rosterGenerate a rotating roster from people and shift patterns. Exports CSV or an ICS calendar.F09TimesheetStart, stop, annotate. Daily and per-project totals stored on this device, exportable as CSV.F10Stage clockFull-screen clock or countdown that changes colour when you run over. For the stage monitor.Time
Zones, working days, and the countdown before a meeting.
G
G01Unit convertLength, mass, temperature, area, volume, speed, pressure, data and energy — including ping and catty.G02Radix convertAny base from 2 to 36, with big-integer support and digit grouping.G03PercentageShare of total, change, discounts, and before/after tax — the six percentage questions.G04Expression calculatorType a whole expression — functions, variables, parentheses. Hand-written parser, no eval.G05StatisticsPaste a column of numbers for mean, median, standard deviation, quartiles and a histogram.G06LoanEqual-payment amortisation with grace periods and prepayment, and a full schedule to check.G07Compound interestCompound growth for lump sums and regular contributions, with an inflation-adjusted view.G08Utility billTiered electricity and water bills. The rate table ships with defaults and is fully editable.G09Split billSplit a bill unevenly, per item, with service charge and tip — and who owes whom.G10Random drawDraw names, pick winners, split groups, roll dice. From getRandomValues, with a verifiable seed.Calculate
Units, interest, bills, draws. The expression parser is hand-written — no eval.
H
H01Colour convertHEX, RGB, HSL, OKLCH and LAB, with a screen eyedropper where the browser has one.H02Contrast checkWCAG 2.2 ratio with AA/AAA verdicts and an APCA reading, plus the nearest passing colour.H03PaletteGrow a perceptually even ramp from one colour, or derive complementary and triadic sets.H04GradientLinear and radial CSS gradients with adjustable stops, interpolated in OKLCH to avoid grey middles.H05Shadow & border CSSLayered box-shadows, radii and borders with a live preview and copyable CSS.H06Cubic bezierDrag the curve, compare the motion side by side, copy the cubic-bezier() value.H07Type scaleA full type ladder from one ratio, with line-height suggestions and fluid clamp() steps.H08Colour blindnessSimulate the three common colour-vision deficiencies over a palette or a screenshot.H09Aspect ratioScale dimensions proportionally, find the nearest integer ratio, with common device sizes.H10SVG optimiseDrop redundant attributes, round coordinates, output inline-ready SVG. Preview via blob, never inline.Colour
OKLCH ramps, WCAG contrast, CSS generators.
I
I01Image convertWebP, AVIF, JPEG and PNG with quality control and a before/after size readout. Encoded locally.I02Image cropCrop, resize, rotate and flip, with ratio locking and exact output dimensions.I03EXIFSee what a photo carries, GPS and device included, then strip it and re-export.I04Redact screenshotPaint solid or mosaic redactions. The pixels are actually replaced, not covered by a layer.I05Join imagesStack or line up several images into one, with gap and background control.I06Video frameOpen a local video, step to the frame you want, save it as PNG or JPEG. Nothing is uploaded.I07QR codeQR codes for URLs, WiFi, vCards and plain text, with error-correction control. SVG or PNG out.I08Scan codecameraScan QR and common 1D barcodes from the camera or an image. Nothing is recorded or sent.I09FaviconOne image into a full favicon set and apple-touch-icon, multi-size ICO plus the HTML to paste.I10Images to PDFCombine scans or screenshots into one PDF with paper size and margin options, assembled in-browser.Media
Canvas and Workers, in place. There is no upload button.
J
J01Subnet calculatorCIDR arithmetic for IPv4 and IPv6 — network, broadcast, usable range, mask and subnetting.J02URL inspectBreak a URL into parts, edit the query, and strip utm_-style tracking before copying.J03User agentBreak a UA string into browser, engine, OS and device — and show your own.J04Device infoScreen, DPR, colour gamut, memory, cores and feature support. Read-only, for filing bug reports.J05Taiwan ID formatsCheck digits for Taiwan ID, ARC, business number and mobile formats. Pure arithmetic, no lookup.J06BMI & TDEEBMI, basal metabolic rate and total daily energy expenditure, with weight-category bands.J07Volumetric weightDimensional weight from L×W×H against actual weight, with switchable carrier divisors.J08Cooking convertScale servings, convert cups and spoons to grams by ingredient density, and oven temperatures.J09NotepadMarkdown notes kept in this browser on this device. Works offline, exports in one file.J10Checklist & matrixRelease checklists and weighted decision matrices. Save several, print them, export Markdown.Network & life
Network arithmetic, plus a few things for after work.