OneDev Tools
Free, fast, and privacy-focused developer tools.
No sign-up required. Website tools run in your browser.
222 tools · Free · Website tools run locally
View the source on GitHubDeveloper tools that stay on your machine
OneDev Tools is a collection of utilities for everyday engineering work: formatting JSON, decoding JWTs, hashing files, generating QR codes, converting units, drafting CSP headers, and more. Every website tool runs as JavaScript in this tab. The optional MCP endpoint is a separate hosted service and processes only requests explicitly sent by an MCP client.
That browser-first design is the product. Paste an access token into a website JWT decoder, a customer export into a JSON formatter, or a private key into a Base64 tool and you should not have to wonder which log file on someone else's server now has a copy. Hosted formatters that upload the payload are convenient until the payload is production data.
The site is free, has no accounts, and does not gate features. Google Analytics records page views so we can see which tools people open. Website tool input stays in the browser; MCP clients send their chosen inputs to the hosted endpoint. Read the privacy policy and about page if you want the full picture, including how we handle explanatory copy and AI pricing tables in the editorial policy.
How to pick a tool
- Start from the category if you know the job (JSON, Hash, Regex, PDF). Each category page explains when to use the suite and which mistakes to avoid, then links into the individual tools.
- Use search in the sidebar if you remember the name (slug generator, cron explainer, HMAC).
- Prefer a local CLI for multi-hundred-megabyte files or air-gapped policy. A browser tab will run out of memory before a well-written command-line tool does.
- Do not treat encoding as encryption. Base64, JWT decode, and URL encode are not a vault. Hash tools verify integrity; they do not hide secrets.
What we will not do
We will not ask you to sign in to format JSON. We will not upload your PDF to compress it. We will not run your prompt against a hosted model from the AI token counters. Those pages estimate tokens and cost from published tokenizers and price lists. If a page cannot do the job honestly in the browser, we would rather omit the feature than fake a server round-trip.
MCP Server
OneDev Tools in your AI assistant
Connect our hosted MCP server to ChatGPT, Codex, Claude, or another compatible client. Use JSON transforms, hashes, JWT inspection, ID generation, CSV/YAML conversion, cron helpers, and time conversion without leaving your workflow.
JSON Tools
Format, validate, compare, and convert JSON in this browser. Nothing is uploaded.
JSON Formatter
Pretty-print is not the hard part. The first syntax error is, and JSON will not mention the second one until you fix the first.
JSON Validator
Check whether a document is valid JSON and jump to the first parse error.
JSON Diff
Compare two JSON values structurally. Key order and whitespace do not count as changes.
JSON → Table
Turn a JSON array of objects into a sortable table you can copy as CSV or Markdown.
JSON Visualizer
Browse a JSON document as an expandable tree and search for keys or values.
Type Generator
Infer TypeScript interfaces or Go structs from a sample JSON payload.
Path Tester
Run JSONPath expressions against a document and inspect the matched values.
Relationship Visualizer
View object relationships as a node graph you can pan and zoom.
PDF Tools
View, split, merge, compress, watermark, redact, and sign PDFs in this tab. Files are not uploaded to us.
PDF Viewer
View PDF files right in your browser with page navigation and zoom — nothing is uploaded.
PDF Splitter
Split a PDF or pull out specific pages by range, then download the result.
PDF Merger
Combine several PDFs into one document and drag pages to reorder them before saving.
PDF Compressor
Adobe and Smallpdf want the file on their server. This page compresses in the tab.
PDF Watermark
Add a text or image watermark to PDF pages, with control over opacity, position, and rotation.
PDF Page Numbers
Add page numbers to a PDF with your choice of position, font size, and starting number.
PDF Redact
Permanently remove sensitive text and images from a PDF by drawing redaction boxes.
PDF Compare
Compare two PDFs side by side and highlight what changed between versions.
PDF Sign
Draw or upload your signature and place it anywhere on a PDF to sign it.
Images to PDF
Combine multiple images into a single PDF, choosing page size and orientation.
Base64 Tools
Encode and decode Base64 for text, files, and images. Encoding is not encryption.
Encode / Decode
Base64 is encoding, not encryption. Anyone who can see it can reverse it.
Image to Base64
Image to Base64 converter online. Convert PNG, JPG, WebP, and SVG images to Base64 data URIs for HTML/CSS embedding. Free image encoder tool.
File to Base64
Encode files to Base64 online. Convert any file to Base64 content for embedding in HTML, JSON, or XML. Free file to Base64 converter.
Image Preview
Base64 image viewer online. Paste Base64 image data and preview instantly. Supports PNG, JPG, WebP, GIF—decode and view Base64 images free.
URL-safe Converter
URL-safe Base64 converter online. Convert between standard Base64 and URL-safe Base64 format (replaces +/ with -_). Free browser tool.
Validator
Base64 validator online. Check if a string is valid Base64 instantly. Detect encoding issues, padding problems, and invalid characters free.
Splitter
Base64 line splitter online. Split long Base64 strings into lines for embedding in code, config files, or PEM certificates. Free browser tool.
Hex / Binary
Base64 to hex converter online. Convert Base64 to hexadecimal or binary representation and back. Free encoding conversion in your browser.
URL Tools
Encode, decode, parse, build, and normalize URLs. Encoding is per component, not the whole string.
Encode / Decode
`encodeURI` and `encodeURIComponent` are not the same function. Using the wrong one is why `?q=a+b` is a space in one API and a plus sign in the other.
Query Parser
URL query string parser online. Parse query parameters into a key-value table instantly. Export as JSON or CSV—free URL parameter extractor.
URL Builder
URL builder online. Build URLs with query parameters visually. Paste existing URLs to parse and edit them—generate URLs free in your browser.
Validator
URL validator online. Check if a URL is valid and see protocol, domain, port, and path breakdown. Validate URLs instantly—free browser tool.
Parts Analyzer
URL parser online. Visual breakdown of URL components: protocol, host, port, path, query, hash. Analyze URL structure instantly and free.
Slug Generator
URL slug generator online. Convert any text to SEO-friendly, URL-safe slugs. Handles unicode and special characters—create slugs instantly free.
Normalizer
URL normalizer online. Normalize URLs: lowercase hostname, sort query params, remove defaults. Standardize URLs for comparison—free browser tool.
Compare
URL comparator online. Compare two URLs semantically and find differences in path, query, or fragment. URL diff checker—free in your browser.
JSON Converter
URL to JSON converter online. Convert URL query strings to JSON objects and back. Handles nested parameters—free query string converter.
Length Checker
URL length checker online. Check URL length against browser and server limits. Avoid "URL too long" errors—free length validator.
Image Tools
Compress, resize, crop, convert, and inspect images in the canvas. Photos stay on this device.
Image Compressor
Online image compressor to reduce file size without losing quality. Compress JPEG, PNG, WebP images directly in your browser—free, no uploads.
Image BG Remover
Make white or light image backgrounds transparent, with adjustable tolerance.
Image Resizer
Resize images by pixels or percentage, with an optional aspect-ratio lock — no uploads.
Image Cropper
Crop images with preset ratios (16:9, 4:3, 1:1) or a freeform selection.
Image Format Converter
Image format converter online. Convert images between JPEG, PNG, WebP, and GIF formats instantly. Free image converter in your browser.
Image Metadata Viewer
View image EXIF metadata — camera, GPS location, date, and settings — with an option to strip it.
Image Color Extractor
Image color picker online. Extract dominant colors and color palette from images. Get hex codes for theming—free color extractor tool.
Image Blur
Image blur tool online. Apply blur or pixelate effects to images. Preview in real-time, then download—free image privacy tool.
QR & Barcode Tools
Create and read QR codes and 1D barcodes in the browser. Treat a WiFi QR like the password it encodes.
QR Generator
A printed QR does not expire. If you put a Wi‑Fi password or a one-time login in it, that secret lives as long as the paper does.
QR Reader
QR code reader online. Decode a QR code from an image or your camera. See the payload instantly — nothing is uploaded.
WiFi QR
WiFi QR code generator. Encode your network name, password, and security type so phones can join with a scan.
vCard QR
vCard QR code generator. Turn a name, phone, email, and company into a contact QR that phones can save.
Barcode Generator
Barcode generator online. Create CODE128, EAN-13, UPC, CODE39, and other 1D barcodes. Download SVG or PNG in your browser.
Barcode Reader
Barcode scanner online. Read EAN, UPC, CODE128, CODE39, and other barcodes from an image or camera.
System Tools
See what this browser reports for OS, CPU, screen, and connection. Optional public IP lookup is opt-in and not used for ads.
System Info
System information tool online. Detect your OS, CPU cores, memory, screen resolution, and GPU info. Check system specs in your browser—free.
Browser Info
Browser detector online. Check browser name, version, engine, and supported features. Detect browser capabilities instantly—free tool.
Network Info
Network info tool online. Check connection type, effective speed, and public IP address. Test your network details—free browser tool.
Media Devices
Media device checker online. List available cameras, microphones, and speakers. Test webcam and mic access—free device detection tool.
Permissions
Browser permissions checker online. Check camera, microphone, location, notification permissions. See what browser has access to—free tool.
Text Tools
Change case, sort lines, diff text, count words, and generate placeholder copy.
String Compare
String comparison tool online. Compare two strings word by word to find differences. Visual textual comparison tool free.
Case Converter
Text case converter online. Convert between camelCase, snake_case, kebab-case, PascalCase, UPPERCASE, lowercase. Change text case instantly free.
Line Tools
Line sorter and text tools online. Sort lines, remove duplicates, trim whitespace, reverse order. Manipulate text lines free in your browser.
Text Diff
Text diff checker online. Compare two text blocks line by line with highlighted additions and deletions. Free text comparison tool.
Find & Replace
Find and replace online with regex support. Search and replace text patterns, preview matches before applying. Free regex replace tool.
Word Count
Count characters, words, sentences, paragraphs, and estimated reading time.
Anagram Finder
Anagram solver online. Find all anagrams of a word or phrase with dictionary validation. Anagram generator free in your browser.
Remove Duplicates
Remove duplicate lines online. Delete duplicate words or lines from text while preserving order. Free duplicate remover tool.
Lorem Ipsum
Lorem ipsum generator online. Generate placeholder text: paragraphs, sentences, or words. Create dummy text instantly free.
Blabber Generator
Random text generator online. Generate readable gibberish text for testing layouts and designs. Fake text generator free.
HTML Tools
Format, check, and extract from HTML you paste. We do not fetch live URLs.
HTML Validator (Basic)
HTML validator online. Check for unclosed tags, invalid nesting, duplicate IDs, and common HTML errors. Validate HTML free in your browser.
HTML Formatter
HTML formatter and beautifier online. Format, prettify, or minify HTML with proper indentation. HTML pretty print free in your browser.
HTML → Text
HTML to plain text converter online. Strip all HTML tags and extract text content only. Remove HTML tags free—get clean text instantly.
Element Extractor
HTML element extractor online. Extract all links, images, meta tags, or scripts from HTML. Parse HTML elements free in your browser.
DOM Visualizer
Nested HTML is easy to write and hard to see. If a selector “should work” and doesn’t, the tree is the problem, not CSS.
HTML → JSON
HTML to JSON converter online. Convert HTML DOM structure to JSON representation. Parse HTML to JSON object free in your browser.
Attribute Cleaner
HTML attribute remover online. Remove inline styles, data attributes, classes, or empty attributes. Clean HTML code free in your browser.
Tag Counter
HTML tag counter online. Count occurrences of each HTML tag and see element distribution. Analyze HTML structure free.
XML Tools
Free XML tools online: XML formatter and beautifier, XML validator, XML to JSON converter, JSON to XML, XML to CSV, minifier, XPath tester, and XML compare. Pretty print XML in your browser with no upload.
XML Formatter
XML formatter and beautifier online. Pretty print XML, format messy SOAP or RSS, and see the first parse error instantly. Free XML pretty print in your browser.
XML Validator
XML validator online. Check if XML is valid, find syntax errors, and validate XML files free in your browser. No upload.
XML Minifier
XML minifier online. Compress XML by removing extra spaces. Minify XML files free in your browser.
XML to JSON Converter
XML has attributes and text. JSON has neither, so something has to give.
JSON to XML Converter
Convert JSON to XML online. Turn JSON into well-formed XML. Free JSON to XML converter in your browser.
XML to CSV Converter
Convert XML to CSV online. Turn XML lists into a spreadsheet table you can open in Excel. Free XML to CSV converter.
XML Escape
XML escape and unescape online. Encode or decode &, <, >, and quotes for XML text. Free XML encoder in your browser.
XPath Tester
XPath tester online. Test XPath queries against XML and see matching nodes. Free XPath evaluator in your browser.
XML Diff
Compare two XML files online. See what changed between XML documents. Free XML diff and XML compare tool.
CSV Tools
Free CSV tools online: CSV to JSON converter, JSON to CSV, CSV viewer, open CSV in browser, CSV to Excel-friendly tables, CSV to SQL, CSV to Markdown, TSV converter, and CSV compare. Convert CSV files with no upload.
CSV to JSON Converter
A comma is not the only separator. Excel in Europe exports semicolons, and a leading zero in a zip code is data until JSON turns it into a number.
JSON to CSV Converter
Convert JSON to CSV online. Download a CSV you can open in Excel. Free JSON to CSV converter in your browser.
CSV Viewer
CSV viewer online. Open a CSV file as a table in your browser. View Excel CSV without uploading.
CSV Validator
CSV validator online. Check CSV files for errors, broken quotes, and missing columns. Validate CSV free.
CSV Delimiter Converter
Convert CSV delimiters online. Change comma to semicolon, tab (TSV), or pipe. Free CSV to TSV converter.
CSV to XML Converter
Convert CSV to XML online. Turn spreadsheet rows into XML. Free CSV to XML converter in your browser.
CSV to SQL Converter
Convert CSV to SQL online. Generate INSERT statements from a CSV file. Free CSV to SQL converter.
CSV to Markdown
Convert CSV to Markdown table online. Paste CSV and get a GitHub Markdown table. Free CSV to MD converter.
CSV Diff
Compare two CSV files online. See added, removed, and changed rows. Free CSV compare and CSV diff tool.
CSV Transpose
Transpose CSV online. Swap rows and columns in a CSV file. Free CSV transpose tool.
SQL Tools
Free SQL tools online: SQL formatter and beautifier, SQL minifier, SQL validator, JSON to SQL INSERT, string escape, query diff, JOIN visualizer, LIKE tester, and a SQL cheat sheet. Pretty-print PostgreSQL, MySQL, SQLite, SQL Server, BigQuery, and Snowflake in your browser. Nothing is uploaded.
SQL Formatter
SQL is not one language. Pretty-print without a dialect will “fix” Postgres into MySQL, then you paste it into prod.
SQL Minifier
SQL minifier online. Compress SQL by stripping comments and extra whitespace while keeping string literals intact. Free SQL compressor in your browser.
SQL Validator
SQL validator online. Check SQL syntax, find unclosed quotes and parentheses, and see parse errors with line numbers. Free SQL checker, no upload.
JSON to SQL Converter
Convert JSON to SQL online. Turn a JSON array of objects into INSERT statements, optionally with CREATE TABLE. Free JSON to SQL converter in your browser.
SQL Escape
SQL escape and identifier quoting online. Quote string literals and column names for PostgreSQL, MySQL, SQLite, or SQL Server. Unescape pasted SQL too.
SQL Diff
Compare two SQL queries online. Format both, then diff. Whitespace and keyword case do not count as changes. Free SQL compare tool.
SQL JOIN Visualizer
SQL JOIN visualizer online. See INNER, LEFT, RIGHT, FULL, CROSS, SEMI, and ANTI joins with sample tables and result rows. Free SQL join explainer.
SQL LIKE Tester
SQL LIKE tester online. Test % and _ wildcards, ESCAPE, and case-insensitive ILIKE against sample strings. Free LIKE pattern matcher.
SQL Explainer
SQL query explainer online. Break a SELECT, INSERT, UPDATE, or DELETE into clauses in plain English. Free SQL explainer in your browser.
SQL Cheat Sheet
SQL cheat sheet online. Joins, data types, window functions, dates, and NULL handling for PostgreSQL, MySQL, and SQLite. Free searchable SQL reference.
Break Tools
Take a break from coding with relaxation tools. Pomodoro timer for focus sessions, ambient sounds, breathing exercises, and calming visuals—free productivity and wellness tools.
Pomodoro Timer
A focus timer with 25/5 and 50/10 presets and a chime when each session ends.
Ambient Rest
Full-screen calm backgrounds with rain or café sounds to help you focus and recharge.
Minimal Clock
A large, distraction-free fullscreen clock with analog or digital display.
Zen Motion
A nostalgic bouncing-shape animation to rest your eyes between sessions.
Breathing Timer
Guided breathing with configurable inhale, hold, and exhale — including box breathing and 4-7-8.
Convert Tools
Convert CSS units, length, data size, time, color, and number bases. Formulas and assumptions are on each page.
CSS Units
Convert between px, rem, em, vw, vh, pt, and percentages, with live results.
Length
Convert between mm, cm, inches, feet, meters, km, and pixels at any DPI.
Screen / Resolution
Work out screen dimensions, DPI, and PPI from a resolution — or the other way around.
Time
Convert between milliseconds, seconds, minutes, hours, and days in human-readable form.
Data Size
Convert between bytes, KB, MB, GB, and TB using decimal (SI) or binary (IEC) units.
Angle
Convert between degrees, radians, gradians, and turns, with a visual arc preview.
Number Base
Convert between binary, decimal, hexadecimal, and octal, with a bit-by-bit view.
Typography
Convert px, pt, em, and rem for typography, and preview line-height and type scale.
Color
Convert between HEX, RGB, RGBA, HSL, HSLA, and HSB, with a live color preview.
Date & Time Tools
Free date and time tools: Unix timestamp converter (epoch to date), time zone converter, world clock, date calculator, ISO 8601 parser, and time ago. Convert timestamp to date in your browser, no signup.
Unix Timestamp Converter
Ten digits is seconds. Thirteen is milliseconds.
Time Zone Converter
Time zone converter online. Convert a time between New York, London, Tokyo, and any city. Free timezone converter in your browser.
ISO 8601 Date Converter
ISO 8601 converter online. Parse ISO dates and durations like P3DT4H. Free ISO 8601 date format tool.
Date Calculator
Date calculator online. Add or subtract days, weeks, or months from a date. Free add days to date tool.
Time Ago
Time ago calculator online. Convert a timestamp into "3 hours ago" or "in 2 days". Free relative time converter.
World Clock
World clock online. See the current time in UTC, New York, London, Tokyo, and more. Free world clock.
Duration Calculator
Duration calculator online. Find the time between two dates. Free date difference and elapsed time calculator.
Date Format Converter
Date format converter online. Get ISO, RFC 2822, Unix, Excel serial, and more from one date. Free date format tool.
CSS Tools
Format CSS and generate gradients, shadows, filters, and keyframes with a live preview.
Formatter
CSS formatter and beautifier online. Format CSS code with proper indentation. CSS pretty print and code beautifier—free in your browser.
Minifier
Compress CSS by stripping whitespace and comments to shrink file size.
Prefix Cleaner
CSS prefix remover online. Remove vendor prefixes (-webkit-, -moz-, -ms-, -o-). Clean up CSS autoprefixer output—free tool.
CSS Gradient Generator
Create linear, radial, and conic gradients with a visual editor, multiple color stops, and live preview.
Transition
CSS transition generator online. Create CSS transitions with live preview. Generate smooth animations—free transition builder.
Bezier Curve
CSS cubic-bezier editor online. Interactive curve editor for timing functions. Create custom easing—bezier curve generator free.
Keyframes
CSS keyframes generator online. Create @keyframes animations with editable stops. CSS animation builder—free keyframe editor.
Box Shadow Generator
CSS box shadow generator online. Create box-shadows with multiple layers and presets. Live preview—free shadow generator tool.
Text Shadow Generator
CSS text shadow generator online. Create text-shadow effects with live preview. Multiple shadow layers—free text shadow tool.
Filter Generator
CSS filter generator online. Generate blur, brightness, contrast, grayscale, and more. Live filter preview—free CSS filter tool.
CSS Text Gradient
CSS text gradient generator. Create beautiful gradient text for headings and logos. Copy CSS code for gradient typography instantly.
Snippets
CSS snippets library online. Ready-to-use CSS: centering tricks, text truncation, accessibility helpers. Copy CSS snippets free.
CSS Layout Tools
Visual playgrounds for Flexbox, Grid, spacing, and aspect-ratio. Output is CSS you paste into a project.
Flexbox Generator
CSS flexbox visualizer and generator. Interactive playground for flex direction, alignment, wrapping, and gap. Generate flex layout code instantly.
Grid Builder
CSS grid generator online. Drag-and-drop grid builder with named areas and auto-placement. Create complex grid layouts visually.
Masonry Layout
CSS masonry layout generator. Create Pinterest-style layouts using pure CSS columns or flexbox fallback. Responsive masonry grid builder.
Responsive Helper
CSS responsive design helper. Generate media queries and common breakpoints for mobile, tablet, and desktop. Responsive layout tool.
Position & Z-Index
CSS positioning playground. Visualize absolute, relative, fixed, sticky positioning and z-index stacking contexts. Layout positioning tool.
Spacing & Gap
CSS spacing generator. Visual margin and padding builder with preview. Generate consistent spacing utilities and layouts.
Aspect Ratio
CSS aspect ratio calculator. Generate aspect-ratio property and padding-hack fallbacks. Visual aspect ratio preview tool.
AI Utilities Tools
Estimate tokens and API cost for common chat models from published tokenizers and price lists. We do not call those APIs with your prompt.
Token Counter
AI token counter online. Count tokens for GPT-5.6, Claude 5, Gemini 3.x, Grok 4.6, and DeepSeek V4. Character count and cost estimation in this browser.
Token Visualizer
Shows how this encoding splits text: leading spaces, camelCase, CJK. Blocks are OpenAI BPE; Claude counts are scaled. Not a generic token counter.
Context Estimator
Window math: system + history + prompt + output must fit. Remaining vs max_tokens, not a token counter online.
Prompt Trimmer
AI prompt trimmer. Trim text to fit token limits with sentence-aware and paragraph-aware modes. Nothing is uploaded.
Embedding Estimator
AI embedding calculator. Estimate tokens, dimensions, and vector DB size for text-embedding-4-large, Gemini Embedding 2, and Cohere.
Cost Estimator
AI API cost calculator. Estimate GPT-5.6, Claude 5, Gemini 3.7 Flash, and DeepSeek V4 bills from published rates (updated 20 Aug 2026).
Cost Compare
Compare AI API costs. Monthly pricing across GPT-5.6 Sol/Terra/Luna, Claude Fable 5 / Opus 5 / Sonnet 5, Gemini 3.x, Grok 4.6, and DeepSeek V4.
Hash Tools
Compute MD5, SHA-1, SHA-256, SHA-512, CRC32, and HMAC checksums, or check a digest against published test vectors. Hashes are not encryption.
Hash Generator
SHA-512 is not password storage. MD5 is not integrity.
MD5 Checksum
Create an MD5 checksum from text or a file. MD5 is fine for accidental corruption checks, not for passwords.
SHA-256 Hash
Generate secure 256-bit SHA-256 hashes from text or files.
SHA-512 Hash
SHA-512 checksum (512-bit). Longer SHA-2 digest than SHA-256. Not a password KDF.
SHA-1 Hash
Create 160-bit SHA-1 hashes, still handy for Git commits and file verification.
CRC32 Checksum
Calculate a CRC32 checksum for quick file-integrity checks.
Hash Identifier
Not sure what a hash is? Detect whether it looks like MD5, SHA-256, bcrypt, or another type.
Compare Hashes
Two hashes can look the same and still differ by one character, and they can look different and still be the same bytes. Eyeballing a 64-character hex string is how a bad ISO ships.
File Checksum
Verify a downloaded file hash against the expected value to confirm integrity.
Hash Test Vectors
Check whether a digest matches published RFC 1321 / FIPS 180 example strings. Not a password cracker.
HMAC Generator
Generate keyed HMAC-SHA256 and HMAC-SHA512 authentication codes.
Hash Converter
Convert a hash between hex and Base64, change its case, or add byte separators.
Git Tools
gitignore, conventional commits, branch names, and Git explainers. Nothing clones your repository here.
Gitignore Generator
Create .gitignore files for Node, Python, Java, Go, Rust, and more — combine presets, then copy or download.
Commit Generator
Conventional commit generator online. Build formatted commit messages with type, scope, and description. Emoji support—create git commits instantly.
Commit Validator
Commit message validator online. Validate against Conventional Commits spec with detailed error explanations. Check commit format free.
Branch Generator
Git branch name generator online. Create feature, bugfix, hotfix branches with ticket IDs. Customizable prefix order—copy branch names instantly.
Workflow Guide
Git workflow cheat sheet online. Learn Git Flow, trunk-based development, and feature branching with visual diagrams. Free Git guide.
Diff Viewer
Compare text with a side-by-side or inline diff, with syntax highlighting and whitespace ignore.
Log Formatter
Git log format generator online. Customize git log output with format placeholders. Generate pretty log commands—copy instantly.
Git Blame Explainer
Git blame explainer online. Paste git blame output and understand each field. Learn blame format visually—free educational tool.
Reset Helper
Git reset helper online. Understand soft, mixed, hard reset with visual diagrams. Generate reset commands safely—free Git tool.
Rebase Helper
Git rebase guide online. Interactive rebase steps with visual explanation. Learn rebase commands—free Git rebase tool.
Config Generator
Git config generator online. Generate git config commands for name, email, aliases, and settings. Configure Git easily—copy commands free.
Alias Generator
Git alias generator online. Create common Git aliases like co, br, st. Custom alias builder—copy git alias commands free.
README Generator
Create a GitHub README with badges, sections, and templates, with a live Markdown preview and download.
License Picker
Choose a license (MIT, Apache, GPL) with plain-English explanations, then generate the LICENSE file.
Secrets Scanner
Git secrets scanner online. Detect API keys, tokens, passwords in code. Client-side scanning—find secrets before committing.
Large File Detector
Large file detector online. Find files too big for Git. Get Git LFS recommendations—detect large files before pushing.
Regex Tools
Test, extract, replace, and explain JavaScript regular expressions. Flavor differences vs PCRE are called out.
Regex Tester
This is JavaScript regex, not PCRE, not Python, not Go. A pattern that “worked in PHP” can fail here for reasons that look like your test string is wrong.
Regex Matcher
Regex match extractor online. Extract all matches and capture groups from text. Export matches as JSON, CSV, or plain list—free regex extraction tool.
Regex Replacer
Find and replace with regular expressions, with live preview and capture-group support ($1, $2).
Regex Explainer
Regex explainer online. Break down regex patterns into tokens with plain English explanations. Understand any regex visually—free regex breakdown tool.
Regex Cheat Sheet
Regex cheat sheet online. Complete regex syntax reference with examples: character classes, quantifiers, anchors, groups, and flags. Free regex guide.
JWT Tools
Decode JWT header and payload, inspect claims and expiry, mint unsigned tokens for UI tests. Decoding is not verification.
JWT Decoder
Decode is not verify. A readable payload is not a trusted user.
Expiration Checker
JWT expiration checker online. Check if your JWT is expired, see time remaining, and view exp/iat/nbf timestamps in human-readable format with timezone support.
Claims Viewer
JWT claims viewer online. View and understand all JWT claims with descriptions. Highlights standard claims (iss, sub, aud, exp) and flags missing recommended claims.
JWT Generator
JWT generator online for testing. Create unsigned or demo JWT tokens for UI testing. NOT for production—generates test tokens with custom header and payload.
Size Analyzer
The JWT spec has no size limit. Your cookie jar and your reverse proxy do.
ID Tools Tools
Generate UUID v4/v7, NanoID, and ULID, and validate UUID layout.
UUID Generator
v4 is random. v7 is time-ordered.
UUID Validator
Check whether a UUID is valid, detect its version (v1–v7), and see why one fails.
NanoID Generator
Generate compact, URL-safe NanoIDs with a custom length and alphabet.
ULID Generator
Generate sortable ULIDs with a timestamp component, and see how sorting works.
Cron Tools
Build, explain, and preview cron expressions, including timezone and DST caveats.
Cron Generator
Build 5-field or Quartz cron expressions with a visual builder and presets.
Cron Explainer
Five fields is Vixie. Six is Quartz.
Next Run Calculator
Cron next run calculator online. Show next 10 scheduled runs with timezone support. DST-safe cron schedule preview—free cron calculator.
Cron Validator
Validate cron syntax, check field ranges, and get helpful error messages.
Cron Presets
Cron expression examples and presets. Copy-paste ready cron expressions for common schedules. Every minute, daily, weekly, monthly—cron cheat sheet.
Human to Cron
Natural language to cron converter online. Build cron expressions with dropdowns. Human-readable cron builder—convert schedule to cron free.
YAML Tools
Validate, format, and convert YAML, including JSON round-trips. Comments are usually dropped on re-serialize.
YAML Validator
Validate YAML syntax with clear line-and-column error messages.
YAML Formatter
Format and beautify YAML with the indentation you prefer.
YAML to JSON
YAML is not JSON with comments. `NO` is false, `on` is true, and Norway's country code will disappear into a boolean if you don't quote it.
JSON to YAML
Convert JSON into tidy YAML, with control over indentation.
YAML Diff
Compare two YAML files side by side with structural change highlighting.
YAML Linter
Catch duplicate keys, indentation problems, and trailing spaces in YAML.
YAML Key Sorter
Sort YAML keys alphabetically, with an option to recurse into nested maps.
YAML to ENV
Flatten YAML into .env format, with custom separators for nested keys.
Kubernetes Tools
Inspect, diff, and split Kubernetes YAML. We do not talk to your cluster or read kubeconfig.
K8s Inspector
Inspect Kubernetes manifests: detect resource types and check required fields.
K8s Resource Diff
Compare Kubernetes manifests with a semantic diff of added, removed, and changed resources.
K8s Manifest Splitter
Split a multi-document YAML file into separate manifests and download them as a ZIP.
K8s to Helm
Turn Kubernetes manifests into a Helm chart with generated values and templates.
K8s API Checker
Check manifests for deprecated or removed Kubernetes APIs by cluster version.
Security Tools
Draft CSP and CORS headers, test password strength locally, and read HTTP security references. This is not a pentest of your site.
CSP Generator
Build a Content Security Policy visually and get warnings about unsafe directives.
CORS Generator
Assemble Access-Control headers by choosing origins, methods, and options.
Password Tester
Check password strength with entropy, estimated crack time, and dictionary checks — entirely in your browser.
HTTP Status Codes
A quick reference to every HTTP status code, explained with examples.
X-Frame-Options
Understand X-Frame-Options and how DENY and SAMEORIGIN help prevent clickjacking.
Security Headers
A cheat sheet of HTTP security headers, each explained with examples.
OWASP Top 10
An interactive checklist for tracking OWASP Top 10 (2021) coverage, with examples.
Misconfig Detector
Scan headers and config files for common security misconfigurations.
Headers Checklist
Secure headers implementation checklist. Framework-specific snippets for NGINX, Apache, Node. Security headers setup guide.
Password Storage
Password storage best practices generator. Algorithm recommendations, salt, pepper, cost factors. Secure password hashing guide.
Threat Model
Run a quick STRIDE-style threat model with risk levels for your web app.