I Built a Free Developer Toolkit Where Your Data Stays in Your Browser
As developers, we constantly need small tools.
Format some JSON.
Decode a JWT.
Encode a string with Base64.
Generate a UUID.
Convert a Unix timestamp.
Test a regular expression.
None of these tasks should be complicated.
But I noticed something annoying: I often ended up opening a different website for each task.
And when the data contained API responses, JWTs, configuration files, or other sensitive information, I always had the same question:
Where does my data actually go?
So I decided to build my own solution.
Meet MyKitApp
I built MyKitApp, a collection of free online developer tools designed to be fast, simple, and privacy-friendly.
You can try it here:
The main idea is simple:
If a tool doesn't need a server, why send the data to a server?
MyKitApp is designed around browser-based processing, so your data can stay in your browser instead of being unnecessarily uploaded to a backend.
What can you do with it?
There are currently tools for several common developer tasks.
JSON
- JSON Formatter
- JSON Validator
- JSON Minifier
- JSON Viewer
- JSON to XML
- JSON to YAML
- JSON Escape / Unescape
Encoding
- Base64 Encoder
- Base64 Decoder
- URL Encoder
- URL Decoder
- HTML Encoder
- HTML Decoder
Security & Authentication
- JWT Decoder
- JWT Generator
- SHA-256 Hash Generator
- MD5 Generator
Generators
- UUID Generator
- Password Generator
- Random String Generator
- Lorem Ipsum Generator
- Barcode Generator
- QR Code Generator
Date & Time
- Timestamp Converter
- Unix Timestamp Converter
Code Formatting
- SQL Formatter
- HTML Formatter
- CSS Formatter
- JavaScript Formatter
- Markdown Formatter
Regex
- Regex Tester
The goal isn't to build the biggest collection of tools possible.
I want these tools to be the kind of utilities developers can bookmark and come back to whenever they need them.
Why browser-based?
Consider a simple JWT decoder.
A JWT can contain information about users, permissions, services, or internal applications.
If all you want to do is inspect the token payload, there is often no technical reason to send that token to a remote server.
The same applies to many other developer tasks.
For example:
JSON formatting
Base64 encoding/decoding
URL encoding/decoding
UUID generation
Hash generation
Regex testing
Timestamp conversion
Code formatting
These operations can often be performed directly in the browser.
That means:
Your input
↓
Your browser
↓
Result
instead of:
Your input
↓
Remote server
↓
Processing
↓
Response
I think the first architecture should be preferred whenever the task doesn't actually require a backend.
Fast, Private, Free
MyKitApp currently focuses on three principles:
Fast
No account and no unnecessary upload/waiting workflow.
Private
The tools are designed to process data in the browser whenever possible.
Free
No subscription is required to use the tools.
The idea is to make common developer utilities feel more like a small toolbox than another SaaS application.
A small example
Imagine you receive a large JSON response from an API.
Instead of installing another application, you can open the JSON Formatter, paste the response, and immediately get readable JSON.
Or you receive a JWT during development and just want to inspect its header and payload.
Open the JWT Decoder, paste the token, and inspect it directly in the browser.
The goal is to remove friction from these tiny tasks.
What I'm planning next
This is still an early project.
Some of the things I'd like to improve include:
- More developer tools
- Better keyboard shortcuts
- More powerful JSON tools
- More code formatters
- Better mobile support
- More privacy-focused utilities
- Offline/PWA support
- Better developer documentation
- More language support
I'm also interested in understanding which small developer tasks people repeat every day.
Because that's probably where the next useful tool should come from.
I'd love your feedback
If you build software, I'd love to know:
What's the developer tool you use most often?
And more importantly:
What's a small developer task that still feels unnecessarily annoying?
I'm building MyKitApp as a practical toolbox for developers, so suggestions are very welcome.
Try it here:
If you find a useful tool that's missing, let me know in the comments.
Top comments (1)
Hello Glad to see you, I am Kane Lim from Hong Kong. I have over 10 years of development experience. I am writing this because your post was interesting.
The browser first architecture is exactly the right direction for this category. I would strengthen the privacy model further by making the application fully offline capable with a service worker, IndexedDB for optional local history, strict Content Security Policy, zero third party telemetry, and explicit memory cleanup after sensitive operations.
For larger JSON and formatting workloads, Web Workers would prevent expensive parsing and AST transformations from blocking the main thread. Streaming parsers could also handle multi megabyte payloads without unnecessary memory duplication.
I would add a privacy verification panel showing whether each operation is local, network dependent, or requires external services. That turns a technical implementation detail into a trust feature.
Another powerful addition would be shareable tool configurations encoded entirely in the URL hash, keeping the actual sensitive input local.
This could become a genuinely useful daily toolbox. I would enjoy exchanging ideas around the offline architecture and security model.