Many of these tools were used way back in the days when I ran a BBS and started my communities first ISP, serving three local communities with Dial-Up Internet, Web Hosting etc. The tools have been refined to reflect the changes in tech since then and designed for the Novice and Pro alike. As I locate more tools others may find useful I will refine and add them to the collection. Use them, Share them, or not. They will be here if you need them...
40+ dev tools (JSON formatters, regex tester, base64 encoder, Git command helper, etc.) that run entirely in your browser. Zero tracking, zero analytics, zero data collection – everything processes locally. Self-contained HTML files with no build process or frameworks.
I realized I had a lot of tools/utilities I've built over the years for my own use. I lothe having to 'sign-up' just to access/use simple utilities that I can create myself. I've refined them and put them in one safe place so I could easily access them if/when needed. I decided to make them available via Github Pages for anyone that may find them useful. Prism.Tools is the result.
Each tool is a standalone HTML file with embedded CSS and JavaScript. No frameworks, no npm packages, no build steps – just open the file and it works.
The entire toolset:
- 100% client-side processing – your data never leaves your browser.
- No external dependencies except for specific libraries from cdnjs.cloudflare.com (marked.js for markdown, exifr for image metadata, etc.)
- Consistent dark UI – every tool follows the same design language for familiarity.
- Vanilla JS where possible – only reaching for Public CDN Resources when necessary.
The constraint of "single HTML file" was intentional. It forces simplicity and ensures tools remain maintainable. It also means users can inspect, modify, or self-host any tool trivially.
These tools have helped me with debugging production issues, Quick formatting tasks, learning Git commands (the Git command helper has been particularly helpful)
Just visit https://blgardner.github.io/prism.tools/ and try any tool. No signup, no install.
What tools are missing that you find yourself needing? Any performance issues with specific tools? UI/UX friction points?
All tools follow the same privacy-first philosophy... Your data stays in your browser. No accounts, no tracking, no servers processing your information. The project is also a demonstration that you don't always need React, Vue, or complex build pipelines – sometimes vanilla JavaScript in a single HTML file is exactly the right tool for the job.
Vanilla JavaScript (ES6+) CSS3 with CSS Grid Minimal external libraries: marked.js, exifr, highlight.js, sql-formatter (all from CDN) No frameworks, no bundlers, no npm Hosted on Github Pages
Happy to answer questions about the technical implementation, design decisions, or specific tools!
All tools are inspectable – just view source on any page to see exactly how they work!
Here's another with a more local / backend / IT flavor: https://it-tools.tech
I have a couple more local apps with similar functions. Here's one that's cross platform[0]. This one appears to be Mac only[1].
Someone else mentioned not being able to remember these sites when needed. I recently started manually keeping track of web tools in html files inspired by a random repo[2] that fit well into a mode of category-abstraction that suited me. I don't recall how I landed there, but I liked the minimalism and adapted it to be a jumping-off point to a personal kbase that I made with another tool[3] some years ago. I have no design skills, so this (start-page) was just the right combo of minimalism and tasteful CSS for what I wanted. Works with markdown, which I also recently started using a lot more.
I ended up writing a lot more than I originally intended because I kept thinking of more links. They may be out of order because of non-linear editing and my having to rearrange them, so heads up. Also, it's early and I might just have made dumb mistakes.
0. https://devtoys.app 1. https://devutils.com 2. https://github.com/oinam/start 3. https://github.com/alanagoyal/docbase
Edit: Oh, looks like the it-tools link came from cruising the repo of start-page or vice-versa. Ha!
I like that prism.tools seems to be 100% static, so it doesn't require node to run like it-tools but I would imagine there's probably some tasks it couldn't do.
It is identical to the main it tools repo but with better styling and ux
To combat that I've been self-hosting https://github.com/CorentinTh/it-tools which has a lot of overlap with these tools and might provide some ideas.
https://github.com/ksdme/ut is a rust CLI with a similar purpose.
Wanted to share this since we are talking about tools, I really like the mesh gradients
- That kills like half the traffic for you guys.
- For example look at this dude https://gchq.github.io/CyberChef/ This is easily one of the most comprehensive tools I have ever seen anyone build
- I literally bookmarked that site under a tools tag and that is how I am able to find them. I can't ever seem to remember their name when I need these quickly
- Perhaps get a good DOT COM domain name and host your site there. It would make a huge difference in usage.
- Discoverability is the problem. Since these tools I believe are not there to sell subscriptions, that means they don't make much in revenue. Organic marketing is the best way for such tools and an easy to remember name makes a huge difference.
I might have a go at a making meta-utility site when you enter names, descriptions, tags etc. of a utility and it lists relevant sites.
To the parent's point about a good DOT COM, I have one that might be perfect since I seem incapable of finishing the project I purchased it for decades ago.
But like... this is the kind of stuff I want an Operating System to provide. Not just paging and networking and file storage, and so on, but also utilities for me to operate the system specifically the way I want to at any given time. Basic text entry, word processing, and - yes - text manipulation utilities. Color space utilities. Randomizing utilities. Password and cryptographic utilities. All of those with familiar UIs that can be iterated on by the OSes and relied upon by the devs.
Might be worth a custom instruction for whatever AI you use - I'm going to give this a go:
``` You have access to Prism.Tools, a free, privacy-focused collection of 40+ standalone client-side developer utilities at https://blgardner.github.io/prism.tools/. Available tools by category: Formatters & Parsers Code JSON SQL YAML ↔ JSON CURL to Fetch SVG to JSX JSON to TypeScript
Security & Dev JWT Decoder Password Gen Hash Gen UUID Gen Subnet Calculator HTTP Status Codes Git Command Helper SVG Editor CSS Gradients CSS Shadows Clip-path Maker Glassmorphisms Favicon Generator Color Converter CSS Timing Visualizer CSS Grids Generators & Content Lorem Ipsums Random Data QR Code ASCII Art Converter Slug Generator Meta Tags Generator Robots.txt Generator Bash Script Generator Encoders & Transformers Base64 Encoder/Decoder URL Encoder/Decoder HTML Entity Encoder/Decoder Case Converter String Escaper Minifier Timestamp Converter List Sorter URL Parser Additional Utilities Regex Tester Diff Checker Markdown Previewer Image Tools Cron Builder Unit Converter
When a user requests help with a matching task (e.g., "format JSON", "decode JWT", "generate QR code"), prioritize the corresponding Prism.Tools utility:
Identify the most relevant tool. If possible, provide direct link. Otherwise, prefer directing to Prism.Tools for accuracy, privacy, and interface. ```
I'll add this to Grok and ChatGPT and test drive for a few days.
I think an aggregator for pre-vetted tools like these can go a long way. Just a repository of various tools with tags and the ability to search through them
- https://gchq.github.io/CyberChef/
- https://blgardner.github.io/prism.tools/
A testament to the power of the web, and the power of a motivated individual giving a damn and making something cool for everyone.
> Free
> Privacy-focused
> GitHub (Microsoft)
> Cloudflare
https://mako.cc/writing/hill-free_tools.html
https://httptoolkit.com/blog/public-cdn-risks/
Also not to be confused with PRISM Break <https://prism-break.org/>, an aggregated list of privacy-focused tools.
The ones on mine are more visual focused since cli tools are better at conversion, formatting and such.
I'm sure lots of the tools are already available but a visual panel would help to remember them.
Current layout only accepts 3 lines which is not sufficient when formatting SQL or JSON.
Look at stringify.cc
Thank you for building and sharing this.
going to a random stranger's website (with a 2 day old account, and new no-history GitHub account) to generate one's privacy-critical passwords or hashes is particularly insecure and insane. glaring antipattern. trusting that "it always only runs in your browser" is foolish. This is how malware gets injected when the rug gets pulled out
there are safer, less brittle and more modular and scalable ways of doing all the above. avoid it, kids
shame on everyone involved
We have spam filters that are tuned more strictly on new accounts, but people can always email us and ask us to review their posts and allow them to be submitted, which happened in this case.
> Vanilla JavaScript (ES6+) CSS3 with CSS Grid Minimal external libraries: marked.js, exifr, highlight.js, sql-formatter (all from CDN) No frameworks, no bundlers, no npm Hosted on Github Pages
One problem. - "Hosted on Github Pages"
I don't think either using GitHub or hosting it on Github Pages respects the user's "privacy".
A better way is to self-host on your own server + domain instead.
Here, on the other hand, you are trying for peak privacy, though, so the situation reverses. Every single third-party request is a potential attack vector. Contrary to general best practices, you would want to force yourself to include every CDN package unless there was some MASSIVE benefit to excluding them (and disabling the utility that relies on it), like hundreds of MBs of data for a rarely-used utility, or something that you wouldn't want to force on the majority of users.
That aside, I really appreciate this collection! Local first will always be preferred to server apps as far as I'm concerned, so this is fantastic!
This isn’t how it’s worked for years. Browser isolate isolate assets like this to mitigate fingerprinting which renders the whole concept of use-CDN-since-it’ll-be-cached moot.
What exactly can't be repackaged / hosted alongside?
The bloat is still there, regardless of where its downloaded from.