91 free developer & designer tools that never upload your data

Free developer and designer tools that run entirely in your browser — encode, format, convert, hash, generate and inspect. Nothing is ever uploaded.

Strings & Text

Transform, count, clean and reshape text.

• Case Converter — camelCase, snake_case, kebab & more
• Slugify — URL-safe slugs from any string
• Word & Char Count — Chars, words, lines, read time
• Line Tools — Sort, reverse, dedupe, trim lines
• Find & Replace — Bulk replace with regex support
• Regex Tester — Live match highlighting, groups, flags
• Text Diff — Compare two blocks line by line
• Reverse Text — Flip characters, words or lines
• Whitespace Cleaner — Trim, collapse, strip blank lines
• Word Frequency — Rank words, chars or lines by count
• NATO Phonetic — Spell text as Alfa Bravo Charlie

Encode & Crypto

Encode, decode, hash, cipher and inspect.

• Base64 — Encode / decode, UTF-8 safe
• URL Encode — Percent-encode & decode URIs
• Hash Generator — SHA-1 / 256 / 384 / 512 digests
• JWT Decoder — Inspect header & payload claims
• JWT Signer — Build & HMAC-sign a token
• Image → Data URI — Drop an image, get a Base64 URI
• HTML Entities — Escape & unescape entities
• Hex ↔ Text — Bytes to text and back, any base
• ROT / Caesar — Rotate letters, ROT13 & shifts
• Morse Code — Translate text ↔ Morse, with audio
• Backslash Escape — Escape \n \t \" for code literals
• Binary ↔ Text — Text to 8-bit binary and back
• Unicode Inspector — Code points, UTF-8 bytes & entities

Math & Calculators

Convert bases, compute, randomize.

• Base Converter — Bin / oct / dec / hex live convert
• Calculator — Expression evaluator with history
• Random Number — Ranged, batches, copy out
• Unit Converter — Length, mass, data, temperature
• Percentage — Change, of-total, tip & discount
• Roman Numerals — Arabic ↔ Roman, up to 3999999
• Aspect Ratio — Solve W:H ratios & resize
• Number Formatter — Grouping, decimals, scientific
• Number to Words — Spell out numbers & currency
• Prime & Factors — Primality test & factorization
• CSS Unit Converter — px ↔ rem ↔ em ↔ pt ↔ %

Data & Format

Pretty-print and convert structured data.

• JSON Formatter — Pretty-print, minify & validate
• JSON → YAML — Convert JSON to readable YAML
• CSV ↔ JSON — Tabular to objects and back
• SQL Formatter — Format SQL for 20 dialects
• Byte Size — Humanize & convert data sizes
• XML Formatter — Pretty-print & indent XML / HTML
• Markdown → HTML — Live split preview & HTML source
• .env ↔ JSON — Convert config files both ways
• List → MD Table — CSV / TSV to a Markdown table
• JSON → TypeScript — Generate interfaces from sample JSON

Generators

Conjure IDs, secrets, codes and filler.

• UUID Generator — v4 IDs, bulk, with/without dashes
• Password Gen — Strong, configurable, entropy meter
• Lorem Ipsum — Words, sentences, paragraphs
• QR Code — Encode links & text to a QR code
• Mock Data — Fake people as JSON or CSV rows
• Random String — Tokens by length & charset
• ASCII Art Banner — Big figlet-style text banners

Color & Design

Convert, sample, mix and check color.

• Color Converter — HEX ↔ RGB ↔ HSL with preview
• Contrast Checker — WCAG AA / AAA pass checks
• Palette Builder — Harmonious schemes from one color
• Gradient Maker — CSS gradients with live stops
• Color Mixer — Blend two colors at any ratio
• Color Blindness Sim — Preview palettes under CVD types
• Box Shadow — CSS box-shadow with live preview
• SVG Pattern Generator — Seamless tiling backgrounds as SVG or CSS
• SVG Blob Generator — Organic blob shapes with a copyable path

Time & Date

Timestamps, cron, timezones and spans.

• Timestamp — Unix ↔ human, ISO, relative
• Cron Parser — Explain & preview cron schedules
• Timezone — Compare clocks across the world
• Date Diff & Age — Days between dates, age in detail
• Date Info — Week no, day of year, quarter, leap
• Duration Humanizer — Seconds ↔ human-readable spans

Web & Network

Headers, queries, subnets and the wire.

• Query String — Parse & build URL query params
• Headers & UA — Your browser + header reference
• IP & CIDR — Subnet math, ranges & masks
• URL Parser — Break a URL into its parts
• HTTP Status Codes — Searchable status code reference
• Basic Auth Header — Build & decode Authorization: Basic

Device Test

Probe your mouse, keyboard, screen, gamepad & touch.

• Double-Click Tester — Catch a mouse switch double-firing
• Key Chatter Tester — Detect keys that register twice
• Key Rollover (NKRO) — See every key you hold at once
• Click Speed Test — Measure your clicks per second
• Mouse Button Tester — Every button & the scroll wheel
• Gamepad Tester — Live buttons, sticks & triggers
• Screen / Dead Pixel — Full-screen fields to spot dead pixels
• Multi-Touch Tester — Visualize every touch point

Image

Resize, pad, recolor and reshape images — all in your browser.

• Image Margin — Add colored padding to all 4 sides
• Palette Extractor — Pull dominant colors from an image
• Image Resize — Scale to exact px or by percentage
• Photo Censor — Pixelate, blur or black out parts of an image

Random & Fun

Roll, flip, pick and shuffle.

• Dice Roller — Roll any dice — d6, d20, 3d8…
• Coin Flip — Flip one or many, track odds
• Random Picker — Pick a winner from your list
• List Shuffler — Shuffle or number any list
• Magic 8-Ball — Ask a question, get an answer
• Random Color — Roll surprise colors with hex

Guides

Read the guides for worked examples and background on the formats these tools handle.