The Software Developer's Toolkit: Free Online Tools for Developers
Whether you're debugging a stubborn API response at midnight, scaffolding a new project, or trying to figure out why your cron job didn't fire, developers constantly reach for small, focused utilities. The problem is that many of these tools are buried behind signup walls, cluttered with ads, or limited by freemium restrictions.
That's where FreeWWW.com comes in. FreeWWW is a growing directory of completely free online tools — no accounts, no subscriptions, no catches. In this post, we've rounded up the FreeWWW tools that are most useful for software developers, organized by the kind of work they support. Whether you're a frontend developer, a backend engineer, a DevOps specialist, or somewhere in between, there's something here for you. Many of us here at FreeWWW are software developers, and we use many of these tools when developing FreeWWW applica
Encoding & Data Format Tools
These are the utilities you reach for multiple times a day — the ones worth bookmarking.
Base64 Encoder & Decoder
The Base64 Encoder & Decoder handles both text and file encoding, which makes it useful for everything from embedding images in CSS to inspecting encoded payloads in API responses. It supports standard and URL-safe Base64, optional line wrapping at 76 characters per the MIME spec, and Data URI generation with automatic MIME type detection. Drop in a PNG and you'll get a ready-to-paste data:image/png;base64,... string. Drop in a Base64 string and it'll detect if it's an image and show you a preview. Everything runs in your browser, so nothing gets uploaded anywhere.
URL Encoder & Decoder
If you've ever spent ten minutes figuring out whether your query parameter needs %20 or +, the URL Encoder & Decoder will save you some headaches. It offers multiple encoding modes that mirror JavaScript's built-in functions — Component (equivalent to encodeURIComponent), Full URL (equivalent to encodeURI), a strict Query Value mode, and an option to encode every single character. It also includes a URL parser that breaks any URL into its color-coded components and displays query parameters in a table, plus a bulk mode for processing many strings at once.
JSON Formatter
Unformatted JSON is one of those small annoyances that adds up across a day. The JSON Formatter lets you paste in a messy JSON blob and get clean, indented output instantly. It's the kind of tool you open in a pinned tab and leave there.
Data Format Converter
The Data Format Converter handles conversions between JSON, XML, CSV, and other common data formats. When you're moving data between systems that speak different languages — pulling CSV exports into a JSON-based pipeline, for instance — this tool handles the translation so you don't have to write a throwaway script.
You might also find these handy: the HTML Formatter, the JavaScript Minifier, Obfuscator & Beautifier, the Markdown to/from HTML Converter, and the Number Base Converter for switching between binary, decimal, hex, and other bases.
Security & Auth Tools
Security tooling can be expensive and complex. These free utilities cover the tasks developers encounter most often when working with authentication, encryption, and identity.
JWT Decoder & Generator
JSON Web Tokens are everywhere in modern authentication, and the JWT Decoder & Generator lets you decode, inspect, and generate them without installing anything. Paste in a token and you'll see the header, payload, and signature broken out clearly. It also supports HMAC signature verification for HS256, HS384, and HS512, so you can confirm a token's integrity right in your browser. All processing stays client-side — your tokens and secrets never leave your device.
Hash Generator
The Hash Generator supports MD5, SHA-1, SHA-256, SHA-512, SHA-3, CRC32, BLAKE2, and HMAC hashing. Whether you're verifying file integrity, generating checksums for deployment artifacts, or just need to quickly hash a string for comparison, it covers the major algorithms in one place.
Encoder / Decoder (AES-256 Encryption)
Sometimes you need to send something sensitive through an insecure channel — a config value to a colleague, a key to a staging environment. The Encoder / Decoder uses AES-256 encryption to let you encrypt and decrypt messages with a shared password. All processing happens in the browser, and no data is transmitted to any server.
UUID Generator
Generating UUIDs is one of those tasks that's trivial but slightly annoying without the right tool at hand. The UUID Generator gives you unique identifiers on demand — useful for database seeding, test data, API mocking, or anywhere you need a guaranteed-unique value.
Also in this category: the Password Generator with customizable length and character rules, the SSL Checker for verifying certificate status, and the SSL Toolkit for broader SSL/TLS utilities.
Network & API Tools
Testing APIs, debugging network issues, and verifying DNS configuration are daily tasks for most developers. These tools put that functionality in a browser tab.
API Tester
The API Tester lets you send HTTP requests and inspect responses without leaving your browser. It's a lightweight alternative for quick tests when you don't need a full-featured desktop client — just set your method, URL, headers, and body and fire off the request. It's particularly useful when you're on a machine where you haven't installed your usual tools, or when you need to quickly verify an endpoint while reading documentation.
Webhook Tester
If you're integrating with services that send webhook callbacks — payment processors, CI/CD pipelines, messaging platforms — the Webhook Tester gives you a way to send HTTP requests and test webhook endpoints. It's helpful during development when you need to verify that your endpoint is receiving and processing payloads correctly.
DNS Lookup Tool
When a deployment goes sideways and you're not sure if it's a DNS issue, the DNS Lookup Tool lets you query DNS records directly. Check A records, CNAME records, MX records, and more — useful for verifying that your domain is pointed where you think it's pointed, or diagnosing why a new subdomain isn't resolving.
CORS Tester
Cross-Origin Resource Sharing issues are one of the more frustrating categories of bugs in web development, mostly because the error messages are vague. The CORS Tester lets you test your server's CORS configuration to confirm that the right headers are being sent. Much faster than repeatedly deploying code changes and checking the browser console.
Also worth exploring: the IP Subnet Calculator, What's My IP, the Domain Investigator, the MAC Address Lookup, the Bandwidth Calculator, and the Network Speed Test.
Text & Code Utilities
Developers spend a surprising amount of time wrangling text — comparing outputs, matching patterns, converting formats, and inspecting raw data.
Code Diff Tool
The Code Diff Tool compares code with syntax highlighting and multiple diff views. When you need to see exactly what changed between two versions of a file — or between what you expected an API to return and what it actually returned — a proper diff view is far more reliable than eyeballing it. All comparison happens in your browser, so you can safely paste sensitive code without worrying about it being transmitted anywhere.
Regex Learning & Testing Tool
Regular expressions are powerful and notoriously easy to get wrong. The Regex Learning & Testing Tool lets you write and test patterns against sample text in real time, so you can iterate quickly and see matches highlighted as you go. If you're still building your regex skills, the learning component walks you through the syntax. And if you're looking for a pre-built pattern rather than writing one from scratch, the companion Regex Pattern Dictionary has hundreds of common patterns organized by use case.
Hex Editor
When you need to inspect binary files at the byte level — debugging file formats, examining compiled output, or verifying that a file header matches what you expect — the Hex Editor runs directly in the browser. It's a niche tool, but when you need it, you really need it.
Color Code Converter
Frontend developers and anyone working with UI code will appreciate the Color Code Converter. It converts between HEX, RGB, RGBA, HSL, HSLA, and HSV formats, includes a contrast ratio checker for WCAG compliance, and generates color schemes. It's more developer-oriented than a typical color picker — the focus is on getting the right code format quickly.
Other text and code utilities on FreeWWW include the Text Comparison Tool, the Text Case Converter, the Text Line Processor, the Lorem Ipsum Generator, and the Word Counting Tool.
Web Development Tools
From scheduling tasks to optimizing for search engines, web development involves a lot of configuration and code generation that's tedious to do by hand.
Cron Expression Generator
Cron syntax is one of those things that's just hard enough to remember that you end up looking it up every time. The Cron Expression Generator lets you build cron expressions visually and see a human-readable description of the schedule, which beats staring at five space-separated fields and trying to remember whether the day-of-week field is zero-indexed.
Meta Tag Generator
Writing SEO meta tags by hand is error-prone and repetitive. The Meta Tag Generator produces the title, description, Open Graph, Twitter Card, and other meta tags your pages need, properly formatted and ready to paste into your HTML head. It's a small time saver that adds up if you're working on multiple pages or projects.
Sitemap Generator
The Sitemap Generator creates properly formatted XML sitemaps for your website. If you're launching a new site or adding pages to an existing one, a correct sitemap helps search engines discover and index your content. It's one of those things that takes two minutes with a tool and considerably longer without one.
HTML Editor
The HTML Editor gives you a live-preview HTML editing environment directly in the browser. It's useful for quick prototyping, testing HTML snippets, or demonstrating markup to someone without spinning up a local development server.
CSS Button Creator
The CSS Button Creator lets you visually design buttons and generate the corresponding CSS. Adjust colors, borders, padding, shadows, hover states, and more, then copy the clean CSS. It's faster than tweaking values in a stylesheet and refreshing repeatedly, and it's a good way to explore design options before committing to code.
There's a lot more in this category: the Robots.txt Generator, the .htaccess Generator, the CSS Pattern Generator, the Code Validator Suite, the Favicon Maker, the User Agent Parser, the Browser Capabilities Detector, the Website Responsiveness Test, the QR Code Generator, the Barcode Generator, and the LaTeX Equation Generator.
Project Management & Infrastructure
Software development isn't just writing code. Planning, tracking, diagramming, and documenting are a significant part of the job, and these tools help with all of it.
Bugx Bug Tracker
Yes, a free, full featured bug tracking application! For small, medium, and large teams, Bugx provides everything you'll need. Manage projects, log bugs, track their status, and keep your backlog organized — all from the browser.
Kanban Board
The Kanban Board provides a drag-and-drop project management interface in the style of Trello or Jira boards. If you need a quick, lightweight way to track tasks for a personal project or small team without creating accounts on a SaaS platform, this gets the job done. Your data stays in the browser, and there's nothing to install or configure.
Gantt Chart Creator
When you need to visualize a project timeline with dependencies — for a sprint plan, a release roadmap, or a proposal — the Gantt Chart Creator lets you build professional Gantt charts with task dependencies, milestones, resource tracking, and critical path analysis. It's particularly useful for communicating timelines to non-technical stakeholders who think better in visual formats.
Flowchart Creator
Documenting system architecture, user flows, or decision logic often requires a diagram. The Flowchart Creator lets you build and export flowcharts directly in the browser. Whether you're mapping out a CI/CD pipeline, a user authentication flow, or the logic behind a complex feature, a clear diagram often communicates more than a wall of text in a design doc.
Additional tools in this space include the RACI Matrix Generator for responsibility assignment, the Network Diagram Creator, the Wireframe Creator for UI mockups, the Time Tracking App for logging hours across projects, and the Cheat Sheet Hub with printable reference guides for programming, design, and productivity.
Wrapping Up
That's over 60 tools across six categories, and we only scratched the surface of what's available on FreeWWW. The best part is that none of these require an account, a credit card, or even an email address. Most of them process everything directly in your browser, so your code and data stay private.
Whether you need to decode a JWT at 2 AM, compare two config files, or build a Gantt chart for a project kickoff, there's probably a free tool waiting for you.
Explore these tools and hundreds more at FreeWWW.com — all completely free, no account required.