28 Free Developer Tools

Free essential tools for software development including JSON formatter, Base64 converter, JWT analyzer, hash generator, and cron parser. Covers everything from API debugging to code generation.

Our Developer Tools category provides tools frequently used in daily programming and web development tasks. JSON formatters and validators are essential for API response inspection and debugging. We offer a comprehensive set of encoding tools including Base64 encode/decode, URL encoding, and HTML entity conversion. The JWT decoder safely inspects token contents, while Unix time conversion tools simplify timestamp conversion. Beyond standard tools like UUID generation, hash generation, and cron parsers, we also provide specialized tools like HTTP header inspection, IP subnet calculation, and SQL formatting.

🔐
Base64 encoding/decoding
Convert and restore text and images to Base64 format.
encode
⏱️
Unix time conversion
Timestamp ⇔ Convert human-readable date and time.
Hours.
cron-style parser
Enter a cron expression to display the next execution time.
Hours.
📏
CSS unit conversion
Conversion of px⇔rem⇔em⇔vw, etc.
CSS
🎯
JSONPath Tester
Test and display results of JSONPath queries in real time.
data
📖
HTTP Status Code Dictionary
List, search and detailed description of all HTTP status codes.
development
🔢
radix (numeration) conversion
Interconversion of 2/8/10/Hexadecimal numbers. Includes bitwise operation preview.
development
👁️
HTML previewer
Real-time preview of HTML/CSS/JS. Console output support.
development
🎨
CSS Selector Tester
CSS selector matching check. With detail calculation.
CSS
📦
JavaScript formatting/compression
Formatting, compression, and obfuscation of JS code. Size comparison display.
development
📎
data URL conversion
File⇔Data URL (Base64) mutual conversion.
encode
🏗️
HTML Table Generator
Create HTML tables with GUI. Supports cell merging and Markdown output.
development
📊
Markdown table generator
Create Markdown tables with spreadsheet-like UI.
development
🔖
Bookmarklet Generator
Convert JavaScript to bookmarklet format. Template included.
development
🔤
string generator
Batch generation of random strings, UUIDs, and dummy data.
generation
🔗
link extraction
Extracts and classifies a list of URLs with href and src attributes from HTML source code.
development
HTML5 Validator
Detects syntax errors in HTML code. Reports closing tag and attribute errors.
development
💻
Binary-to-text conversion
Mutual conversion between text and binary (01); also displays UTF-8 byte representations.
development
🌐
IPv4⇔IPv6 conversion
Mutual conversion between IPv4 and IPv6 addresses, supporting IPv4-mapped format.
development
🚀
Batch URL Open
Open multiple URLs at once in a new tab. Convenient for research and comparison.
development
📊
Excel to HTML table conversion
Automatic conversion of Excel and Google Spreadsheet data into HTML tables.
development
📊
Chart Creator Tools
Easily create bar, line, pie, and donut charts. Supports CSV-style and manual data input. Custom colors, title...
development
📐
Create Flowchart
Create flowcharts easily in your browser. Drag and drop start/end, process, decision, and input/output nodes, connect with arrows...
development
🥧
Pie Chart Maker
Create beautiful pie and donut charts by entering data. Features animated rendering, hover effects, color customization, and PDF...
development
📊
Radar Chart Maker
Create radar (spider) charts easily in your browser. Freely customize axes, datasets, and colors for PN...
development
📅
Timeline Maker
Create beautiful timelines by entering events. Display dates, titles, and descriptions with color coding. Alternating left-right layout...
development
🌳
Tree Diagram Generator
Auto-generate tree diagrams (org charts, hierarchy charts) from indented text. Supports horizontal and vertical layouts with 3 color theme options...
development
Venn Diagram Generator
Easily create 2 or 3-set Venn diagrams. Add labels to each region and customize colors. SVG rendering for clear display, PNG...
development

What is the Developer Tools Collection?

The Developer Tools collection is a comprehensive suite of essential utilities for software engineers, supporting tasks from data transformation to security analysis. It includes JSON formatting and validation, Base64 encoding/decoding, JWT token analysis, hash generation, and numerous other developer utilities. Rather than switching between multiple websites or command-line tools, developers access all essential utilities from a single platform, streamlining workflows and increasing productivity for both beginners and experienced developers.

How to Use

Access the main dashboard to browse available tools by category. Each tool typically follows a similar workflow: paste or input your data, select options if applicable, and view instant results. For JSON tools, copy your JSON code into the input area—the formatter automatically prettifies it with proper indentation and syntax highlighting, while the validator confirms structure correctness. Base64 tools decode received data or encode strings for transmission. JWT tools parse tokens to view payload information and verify signatures. Hash generators accept text input and produce cryptographic hashes in multiple formats (MD5, SHA1, SHA256). Most tools provide copy-to-clipboard buttons for convenient output handling without manual selection.

Use Cases

API development relies on JSON tools for testing request/response payloads—developers verify data structure before integration. Authentication troubleshooting uses JWT analysis to inspect token contents without decoding manually. Web form submissions use Base64 encoding when transmitting files or sensitive data safely. Password storage and verification depend on hash generation for security—developers confirm hashing functions work correctly before deployment. Database administrators use hash tools for data integrity checks and deduplication. Security researchers analyze encoded/hashed content in malware samples. DevOps engineers use these tools during CI/CD pipeline development and debugging. Educational settings teach cryptography and data transformation using practical, interactive tools rather than theory alone.

Tips & Insights

JSON formatting reveals hidden structure issues—malformed JSON becomes obvious when auto-formatting fails. Understanding character encoding prevents Base64 decode failures—UTF-8 is standard but verify your source. JWT tokens contain three dot-separated parts; understanding this structure helps manual inspection. Hash functions are one-way—you cannot reverse hashes to get original values, so they're ideal for passwords. Different tools serve different security levels; MD5 is obsolete while SHA256 is current standard. Bookmarking your most-used tools saves navigation time. Combining multiple tools creates powerful workflows; format JSON, then hash it for verification purposes.

Frequently Asked Questions

Can I safely view the contents of JWT tokens?

Yes. The JWT decoder parses tokens within your browser, so sensitive information won't leak outside.

How do I format an API response?

Paste the response into the JSON formatter and it will automatically format it with indentation and display validation results.

Can I use it offline?

Once a page is loaded, most tools work without an internet connection.

How do I choose which developer tool I need from this collection?

Each tool is organized by category (encoders, formatters, generators) with descriptions. Start by identifying your task (formatting JSON, encoding text, etc.) then select the matching tool.

Are all these tools free and do they have usage limits?

All tools in this collection are completely free with no hidden limits. There are no API key requirements or account creation needed.

Can I use these tools programmatically or integrate them into my workflow?

The tools are web-based interfaces designed for manual use. For programmatic use, you'd need to implement the underlying algorithms or use corresponding APIs.

Is my data secure when using these developer tools?

All processing happens in your browser using JavaScript. Your data is never sent to servers unless explicitly required (like for API decoding), making it safe for sensitive content.

Which tools work offline?

Most tools that involve local transformation (formatting, encoding, hashing) work offline once loaded. Tools requiring external APIs require an internet connection.

Are the source code or algorithms available for these tools?

The site is open-source and code is visible through browser developer tools. For specific implementation details or complete source access, check the project repository.

Subcategories

Other Categories