AltCatch
Audit any page for missing alt text and broken images, then export clean Markdown reports
accessibilityalt-textwcag
5New uses
500,000+ Developers Trust Our Tools Collection
All Free Online Developer Tools & Utilities
Explore all 81 professional online developer utilities — 100% free, private, and lightning fast. No signups, no ads, just pure productivity to streamline your coding workflow.
✅ Instant & Free🔒 Browser-Side Only⚡ Optimized Performance📱 Fully Responsive
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Active:developer
30 Tools found
Showing tools in developer
Cron Expression Builder
Write, parse, and validate any standard 5-field cron schedule with next-fire times and plain-English description
cronschedulerdevops
4.838K uses
CSS Beautifier
Format minified CSS into clean, readable code with proper indentation
cssbeautifierformatter
4.654K uses
CSS Minifier
Minify and compress CSS code to reduce file size
cssminifiercompress
4.768K uses
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes instantly
hashmd5sha256
4.787K uses
HMAC Generator
Compute HMAC signatures (SHA-1, SHA-256, SHA-384, SHA-512) via the Web Crypto API with hex, Base64, and Base64URL output. Used for JWT HS256, AWS Sig V4, GitHub webhooks, and API request signing.
hmachmac sha256jwt hs256
4.918K uses
HTML Formatter
Format and beautify HTML code with proper indentation
htmlformatterbeautify
4.676K uses
HTML to JSX
Convert HTML to React JSX: 30+ attribute renames (class→className, for→htmlFor, event handlers to camelCase), inline styles to object syntax, void elements self-closed, HTML comments translated.
html to jsxreact converterclassName
4.922K uses
HTTP Status Codes
Complete searchable reference for every HTTP status code (1xx-5xx) with plain-English descriptions, typical use cases, and RFC 9110 citations — including WebDAV, rate-limit, and captive-portal extensions
http status codesrest apirfc 9110
4.928K uses
JavaScript Minifier
Minify and compress JavaScript code for production
javascriptminifiercompress
4.782K uses
JSON Diff
Semantic JSON comparison — walk two JSON trees and emit path-indexed added / removed / changed records. Ignores whitespace and key order. Distinct from line-by-line text Diff Checker.
json diffjson compareapi debugging
4.918K uses
JSON Formatter
Format, validate, and beautify JSON data with advanced error handling
jsonformattervalidator
4.9125K uses
JSON Schema Generator
Generate JSON Schema (Draft 2020-12, 2019-09, or Draft-07) from any JSON example with inferred types, required fields, and detected string formats (email, uuid, date-time, uri, ipv4).
json schemadraft 2020-12openapi schema
4.911K uses
JSON to TypeScript
Generate clean TypeScript interfaces from any JSON with recursive nested types, array unions, and configurable style
typescriptjsontypes
4.834K uses
JSON to YAML Converter
Bidirectional JSON ↔ YAML converter with custom serializer and YAML 1.2 subset parser tuned for real-world configs (Kubernetes, GitHub Actions, Docker Compose, Ansible). Inline error reporting and one-click direction toggle.
json to yamlyaml to jsonconverter
4.933K uses
JWT Decoder
Decode JSON Web Tokens to inspect header, payload, and claims with expiration check — 100% client-side
jwtdecoderauth
4.962K uses
LLM Token Counter
Estimate token count and API cost for any prompt across GPT-4, GPT-4o, Claude Opus 4.7, Claude Sonnet 4.6, Claude Haiku, Gemini 1.5 Pro and Flash. Live count, 2026 pricing, context-window utilization bar
token countergpt tokensclaude tokens
4.944K uses
Markdown to HTML
Convert Markdown to clean HTML with side-by-side rendered preview. Supports CommonMark essentials plus GFM strikethrough, fenced code, and tables. 100% client-side custom parser.
markdown to htmlmd convertercommonmark
4.916K uses
Meta Tag & OG Previewer
Paste HTML and see live Google SERP, X, Facebook, and LinkedIn previews with length checks and per-rule SEO validation
seometa tagsopen graph
4.823K uses
Number Base Converter
Convert numbers between binary, octal, decimal, hexadecimal, and any base 2-36 with BigInt precision and two's complement support
binaryhexdecimal
4.829K uses
Open Graph Tag Generator
Generate HTML <head> meta tags for Open Graph (Facebook/LinkedIn/Slack), Twitter Card, description, canonical, and theme-color from a simple form. Character-count guidance based on 2026 platform best practices.
open graphog tagstwitter card
4.913K uses
Password Generator
Generate strong, secure passwords with custom options
passwordgeneratorsecurity
4.9103K uses
Password Strength Meter
Offline password strength tester with entropy math, breach-corpus check, pattern detection, and crack-time estimates
passwordsecuritystrength
4.968K uses
Random Number Generator
Cryptographically-strong random integers in any range with no modulo bias — up to 10,000 numbers, optional uniqueness and sort
randomrngdice
4.971K uses
Regex Tester
Test and debug regular expressions with live matching
regextesterpattern
4.891K uses
SQL Formatter
Format and beautify SQL queries with syntax highlighting
sqlformatterdatabase
4.8112K uses
URL Parser
Decompose any URL into protocol, host, port, path segments, query parameters (as a table), and hash using the native WHATWG URL parser. Decoded and raw values shown side-by-side.
url parserquery parametersutm
4.912K uses
UUID Generator
Generate unique UUIDs (v1, v4, v5) for your applications
uuidgeneratorunique id
4.895K uses
XML Formatter
Beautify or minify XML with native DOMParser validation. Works on SOAP envelopes, RSS feeds, sitemaps, Android string resources, SVG, and Office Open XML. 100% client-side.
xml formatterxml beautifiersoap formatter
4.919K uses
YAML Validator
Validate, format, and convert YAML with line-precise errors — ideal for GitHub Actions, Kubernetes, Docker Compose, and Ansible
yamlvalidatorkubernetes
4.847K uses
Why Toolk is the Hub for Free Developer Resources
In today's fast-paced development world, efficiency is everything. Whether you're beautifying JSON data for an API response,formatting complex SQL queries, orencoding binary data to Base64, having the right tools saved in your bookmarks can save you hours of mundane work.
A Commitment to Privacy
Most online tools transmit your data to a remote server for processing. This is a massive security risk when handling private keys, customer data, or proprietary logic. At toolk, we leverage modern browser capabilities to ensure your data never leaves your machine. We use client-side JavaScript for all operations, making us one of the most secure JavaScript-driven tool platforms available.
Expert Utilities for Modern Workflows
Our collection goes beyond simple formatters. We provide essential security tools like asecure password generator andSHA-256 hash generators to help implementing best practices as defined by W3C standards. For designers and frontend developers, our color palette toolsand image encoders simplify visual asset management.
Core Benefits
- ✨Zero cost, zero limits, zero accounts
- 🛡️Industry-standard security (Local-first)
- 🚀Instant feedback with Web Workers
- 📱Works on mobile, tablet, and desktop
Reliable Resources
?Frequently Asked Questions
Are these developer tools really free?
Yes, all tools on toolk are 100% free to use. We do not have any paywalls, premium features, or subscription models. Our mission is to provide high-quality utilities for everyone without charge.
Do I need to sign up to use the tools?
No signup or registration is required. You can use any of our tools immediately, as many times as you want, with no personal information collected.
Is my data secure when using toolk?
Absolutely. All processing happens locally in your browser. We do not transmit your input data to our servers, ensuring your sensitive development data stays private and secure.
What categories of tools do you offer?
We offer a wide range of tools across categories like Data Processing (JSON, SQL, Base64), Text Utilities (Word Counter, Case Converter), Design (Color Palette), and Security (Password Generator, Hash Generator).
The Trusted Utility Platform for Professionals
With over 500,000 users worldwide, toolk has become the go-to destination for developers who value speed and reliability. Our online regex tester,UUID generators, andmarkdown editors are built to professional standards, ensuring you get accurate results every time. Experience a better way to work with our ad-free, clutter-free developer toolset today.
Learn more about our mission