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Free Online Developer Tools

Handy web developer utilities. Format and minify JSON, HTML, CSS, JS, decode JWTs, test regex, and convert timestamps instantly.

Available Developer Tools (26)

JSON Validator

Validate JSON syntax against RFC 8259 standards with line-by-line error messages.

JSON Minifier

Compress and minify JSON data by stripping all whitespace and unnecessary characters.

JSON Tree Viewer

Inspect and navigate nested JSON objects and arrays with an interactive collapsible tree.

JWT Decoder

Decode and inspect JSON Web Tokens (JWT) headers, payloads, and claims locally in your browser.

Base64 Encoder & Decoder

Encode plain text or binary files into Base64 strings, or decode Base64 back into readable text or downloadable files.

Base64 Decoder

Decode Base64 strings back to readable UTF-8 text or downloadable binary files.

URL Encoder & Decoder

Encode query parameters and strings into percent-encoded URL formats, or decode percent-encoded URLs back to text.

URL Decoder

Decode percent-encoded URLs and query strings back to human-readable strings.

UUID / GUID Generator

Generate RFC 4122 compliant Version 4 UUIDs using hardware cryptographic randomness in bulk.

Hash Generator

Calculate cryptographic hashes including SHA-256, SHA-512, SHA-384, SHA-1, and MD5 locally in your browser.

Regex Tester

Test and debug regular expressions with live syntax highlighting and capture groups.

Timestamp Converter

Convert human-readable dates into Unix timestamps (seconds & milliseconds) and vice versa.

Unix Timestamp Converter

Convert Unix epoch timestamps (seconds/milliseconds) into human-readable date & time.

HTML Formatter

Beautify and indent messy HTML markup with clean hierarchical nesting.

CSS Formatter

Beautify and structure CSS stylesheets with clean rule indentation and spacing.

JavaScript Formatter

Beautify unformatted or minified JavaScript and TypeScript code with clean indentation.

HTML Minifier

Minify HTML markup by removing whitespace, comments, and redundant line breaks.

CSS Minifier

Compress CSS stylesheets for production by removing comments, spaces, and duplicate semicolons.

JavaScript Minifier

Minify JavaScript code by removing comments, extra spaces, and redundant line breaks.

Color Converter

Convert colors between HEX, RGB, HSL, HSV, and CMYK with an interactive color picker.

Cron Expression Generator

Build standard 5-part cron expressions interactively with schedule dropdowns.

Cron Expression Explainer

Translate cryptic cron expressions into human-readable English descriptions.

Number Base Converter

Convert numbers between Binary (Base 2), Octal (Base 8), Decimal (Base 10), and Hex (Base 16).

Binary Converter

Convert text strings to binary 0s and 1s and decode binary back to plain readable text.

Hex Converter

Convert text to hexadecimal values and decode hex byte sequences back to readable text.

Essential Web Development, Encoding & Debugging Utilities

Modern software engineering requires rapid debugging, formatting, transcoding, and validating diverse data representations across REST APIs, microservices, and client applications. TheToolMint Developer Tools Suite assembles crucial, distraction-free utilities designed to streamline daily programming workflows right from your browser.

JSON & Code Formatters

Format, validate, prettify, and minify JSON, HTML, CSS, and JavaScript with interactive collapsible tree views and line-by-line syntax error identification.

Security Token & Encoders

Decode JWT headers and claims safely without sending auth tokens over the network. Encode and decode Base64 data, URL strings, and UUID v4 identifiers locally in memory.

Time & Regex Testing

Convert Unix epoch timestamps to human-readable dates across international timezones, and test complex regular expressions with real-time match group breakdowns.

Zero Network Latency & Total Code Confidentiality

Because every developer utility executes directly in your browser's JavaScript V8 engine, you can format production payloads, inspect sensitive authentication tokens, and generate test data without concerns about server logging, network interception, or third-party tracking. Build faster and debug smarter with zero overhead.

Boosting Full-Stack Productivity & CI/CD Pipeline Prep

Eliminate mundane context switching during development sprints. Generate RFC-4122 compliant UUID v4 keys for database mock data, construct and verify complex cron expressions for scheduled background workers, transcode color formats (HEX, RGB, HSL) for design systems, and minify production code to minimize bundle payload bytes. All utilities work seamlessly offline and keep your API secrets private.

Safe Token Inspection & Secret Protection

Pastes containing API keys, Bearer tokens, or private customer records are parsed purely within your browser runtime. You can inspect JWT claims, debug regex patterns, and format JSON trees without leaking sensitive credentials to third-party services or central servers.

Validate API payloads before initiating staging integrations. Identify trailing commas, unescaped quotes, and schema type mismatches instantly with interactive line numbering and actionable error diagnostics.

Other Categories

15 Tools

Image Tools

Free, browser-based image utilities. Compress, resize, crop, convert, enhance, and remove backgrounds with 100% client-side privacy.

16 Tools

PDF Tools

Fast and private PDF tools. Merge, compress, split, convert, rotate, protect, and extract pages entirely in your web browser.

15 Tools

Text Tools

Essential text analysis and formatting utilities. Count words, change case, remove duplicates, sort lines, and compare text differences.

9 Tools

Security Tools

Cryptographically secure generators and inspectors. Strong password generation, random strings, hashes, and token decoders using Web Crypto.

14 Tools

SEO Tools

Search engine optimization helpers. Generate meta tags, simulate Google SERP snippets, preview Open Graph cards, and create robots.txt.

8 Tools

QR & Barcode Tools

Create customizable QR codes for URLs, WiFi, text, vCards, and emails. Generate standard barcodes and scan codes instantly.

0 Tools

Online Calculators

Comprehensive financial, loan, investment, math, and everyday calculators with step-by-step formulas and amortization schedules.

3 Tools

AI & Language Tools

Genuinely zero-cost, browser-native natural language tools. Local text summarization, readability scoring, and sentiment analysis.

8 Tools

Creator Tools

Designed for content creators. Resize YouTube thumbnails, social media posts, banner images, and calculate aspect ratios easily.

13 Tools

Converter Tools

Convert measurements, data units, speeds, temperatures, and numbers between different formats and numeral systems.