Hi HN, I'm Barry and I've built Prism.Tools (https://blgardner.github.io/prism.tools/) – a collection of client-side developer utilities that respect your privacy.
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!
There are lots of these, but this is the first that I've seen that focused on frontend dev a bit more. I've saved it to my list of tools for reference.
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 do like the standalone HTML file approach. With coding agents it's quite easy to build a suite of tools for personal use. Additionally if you review the code, you can trust if it's really private/secure.
The ones on mine are more visual focused since cli tools are better at conversion, formatting and such.
I like initiatives like this but the issue I have mostly is that whenever I have a specific need, say, I need to format a piece of JSON, I would directly google "json formatter" instead of remembering that there is a website with a suite of tools that I can go on and find that specific tool I wanted. And I would probably do the same for all of the tools listed there. It's more convenient, I think, to do a quick search and click on one of the first that came up. I've just never come to leave this habit.
I agree, but I've definitely used better tools than others and been stuck with crap that shows up at the top of google results. And there's great tools like this[0] that I've found through HN but never show up on google
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
Some possibly relevant bookmarks if anyone is working on something similar
- https://gchq.github.io/CyberChef/
- https://blgardner.github.io/prism.tools/
I love these kinds of collections but often don't recall the site in the moment I have a task they could fulfill.
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.
That's exactly why I put this together, not being able to find what I need, when i need it. Now I have one bookmarked page with all the tools! Thanks for the link to your tools, will be checking them out...
Wanted to share this since we are talking about tools, I really like the mesh gradients
This looks great and will definitely check out! I've been using DevToys on my local machine for years but a recent update made it almost unusable.
This website is an absolutely brilliant resource. I've got bookmarks for a few tools that are similar to the ones in your website. But man, this is amazing! Thanks so much for sharing it.
- my gripe with most of these tools is that whenever i actually need one, i can never seem to remember their name.
- 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.
CyberChef is a great tool, thanks for sharing that! One of my main focuses was to create something a user could keep on their own system if they wish. Only coming back to the actual site when/if they want to get latest versions.
CyberChef runs locally as well. It even has a download link for that on the top left of the main page.
I was going to ask. Is a goal here for users to self/locally host if they like?
Yes, you can self host if you’d like as long as you don’t make it public. Be sure to get the latest version from GitHub periodically, or not. If it’s working no need to update.
That ‘dude’ is the UK’s GCHQ. Of Bletchley Park fame.
I was going to post this exact tool to see what the differences were. As others have noted, GCHQ is basically the NSA for Britain.
You know that "this dude" is basically the UK Governments version of the NSA, right?
I was not expecting that. It's really interesting that they are behind this.
Ah you beat me to it ;) I was chuckling when I read that
my big gripe with them is that they aren't part of a "developer" package my operating system offers. I wouldn't, personally, consider any of these utilities "bloatware", if they were just on my machine. They do something useful, even if I rarely need to do those things. But even if we say that those apps would be "bloat" for an OS, I should still be able to open the package manager and get a vendor-supplied package that includes a bunch of utilities like this. Not a third-party "if you know, you know" situation. Windows Development Utilities. Ubuntu devutils. DevToolKit on MacOS. Etc. Included as a toggle on the OS install screen, even.
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.
I’m not sure why, but the first thing I did was check if HTTP status code 418 was listed.
I love what you have here. Thank you for open sourcing your work -- but why the custom license? Why not just do a standard MIT license?
Thanks for making these and for making them available.
A testament to the power of the web, and the power of a motivated individual giving a damn and making something cool for everyone.
You are welcome! I hope you find at least one of the tool useful, if you do then I have succeeded in my quest!
How is an account created two days ago able to post a link? Can the mods comment?
Would there be a way to resize the input/output fields?
Current layout only accepts 3 lines which is not sufficient when formatting SQL or JSON.
Good catch! I will check into that. I’m sure there are other tools with some quirks too. I will be going over them all to make sure issues like this are taken care of, Thanks!
> Free
> Privacy-focused
> GitHub (Microsoft)
> Cloudflare
Which is it? These US megacorporations are respecting neither users’ privacy nor their freedom. Then on top is a proprietary license stating: “No Re-hosting: You may not host these Tools on other websites or public repositories” even if you wanted to host it locally or your own server.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.
Doesn’t “host” imply “host for others”?
...or PRISM the privacy violating government program...
Which is why PRISM Break was created.
Ah, I missed that, coffee has not kicked in yet.
Great work! I really appreciate these tools with the privacy angle!
Thank you! I am a big privacy advocate!
Nice! I made something very similar, but with a focus on frequent daily use, means no clicking required, you can only use keys
Look at stringify.cc
Nice set of tools! It's nice to see there are others that appreciate ad free, no bloat tools!
Can I turn off dark mode?
No, not at this time, maybe in the future. I went dark since it seems to be the pref now.
Is the name choice intentional? I wonder if it was inspired by the notorious privacy busting program.
The name just popped into my head as I was sitting there looking at the main page, I saw how one idea can need multiple tools, like the rays of a prism relying on a single beam of light.
Did you search online for overlap before running with it?
I hate these "browser" tools that actually upload your data to their server for processing, and even if you ignore privacy implications, they also obviously have file size limits, even though the actual work can be done entirely on the client.
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Nice, however:
> 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.
I fail to see how “hosted on Github Pages” has anything to do with the user’s privacy… This is not a snark, I really would like to understand.
It allows Microsoft to collect the traffic data. Generally it also implies the code is also hosted on Microsoft GitHub—which requires an account, accepting ToS, training the Copilot models by interacting with the platform.
Users do have the option to 'Git' or simply download the pages and use them locally, can't get more private than that.
Likewise the CDN's, probably.
CDNs are necessary for some tools, they wouldn't work without. The do CDNs help eliminate bloat.
I mostly do front-end work, so I get why you would default to CDNs - it's more likely that users ALREADY have that CDN link downloaded and cached on their machine than not. It's absolutely an upgrade for 99.9% of most use cases.
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!
> it's more likely that users ALREADY have that CDN link downloaded and cached on their machine than not
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.
> CDNs are necessary
What exactly can't be repackaged / hosted alongside?
The bloat is still there, regardless of where its downloaded from.
Right, including extra user tracking.
it-tools is one I use often and have setup locally.
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.
Thanks for the great feedback and I am very happy you decided to save it to your tool list!