There are hundreds of “developer tools” lists online and most of them are the same 20 things everyone already knows about, VS Code, GitHub, Postman. This isn’t that list.
These are smaller, specific-purpose tools that solve one problem well. The kind of thing you search for when you need it, use it once, forget the URL, and then spend ten minutes searching for it again the next time.
Bookmark the ones relevant to what you build.
Hashing and encoding
Hash generation, when you need to quickly generate MD5, SHA1, SHA256, or SHA512 of a string without writing code or installing anything. Useful for checksums, testing, CTF work, or verifying data integrity.
HashGenerator, darkmintis.dev/hashgenerator
Hash cracking, dictionary attack against MD5 and SHA1 hashes in the browser. Built for CTF beginners who don’t want to set up Hashcat for a quick check.
HashCrack, darkmintis.dev/hashcrack
Base64 encoder/decoder, CyberChef is the standard here. Overkill for simple tasks but genuinely the best tool for anything encoding-related. CyberChef, gchq.github.io/CyberChef
QR codes
Custom QR generation, generate QR codes with custom colors, logo embedding, and multiple format options. Free, no account.
QR code reading, ZXing Decoder Online is useful when you have a QR code image file and want to decode it without using your camera. ZXing, zxing.org/w/decode.jspx
Color and design
Extract colors from any website, paste a URL and get the exact color palette and CSS variables used. Useful for matching a design system or pulling inspiration.
Color contrast checker, WebAIM’s contrast checker for accessibility compliance. Simple, fast, essential if you care about WCAG. WebAIM Contrast Checker, webaim.org/resources/contrastchecker
Coolors, palette generator and explorer. The fastest way to find a working color scheme when you’re starting from scratch. Coolors, coolors.co
Code utilities
Code language conversion, convert code between programming languages. Useful for quick translations between Python, JavaScript, and others without rewriting by hand.
LangSwap, darkmintis.dev/langswap
Code screenshot generator, turn code snippets into clean images for sharing on social media, documentation, or presentations. Multiple themes available.
Carbon, the original code screenshot tool. Still the most polished one out there. Carbon, carbon.now.sh
Regex101, regex tester with real-time matching, full explanation of each part of your expression, and a library of community patterns. The explanation feature alone makes it worth using over alternatives. Regex101, regex101.com
APIs and data
JSONPlaceholder, fake REST API for testing and prototyping. Returns realistic-looking JSON for users, posts, comments, todos without setting up a backend. JSONPlaceholder, jsonplaceholder.typicode.com
Mockaroo, realistic test data generator. When you need 500 rows of fake user data with names, emails, and addresses that look real. Mockaroo, mockaroo.com
Postman Echo, echo service for testing HTTP requests. Sends back exactly what you sent it, useful for debugging request formatting. Postman Echo, postman-echo.com
AI prompt building
Prompt generator for JSON/XML output, builds structured AI prompts that return consistent JSON or XML. Useful when you need AI output you can actually parse programmatically.
Jrompt, darkmintis.dev/jrompt Xrompt, darkmintis.dev/xrompt
Privacy and sharing
Anonymous image sharing, share images via QR code with auto-delete. No account, no compression. Android app.
Anonymous publishing, write and publish without an account or email. Get a shareable link, that’s it.
transfer.sh, command line file sharing. Upload a file via curl, get a link back. Useful for quick transfers between machines. transfer.sh, transfer.sh
Miscellaneous
Crontab.guru, cron expression editor with plain English explanation of what your schedule actually does. Solves the “is this running every hour or every minute” confusion instantly. Crontab.guru, crontab.guru
Excalidraw, hand-drawn style whiteboard for quick diagrams and architecture sketches. The informal aesthetic makes it feel lower-stakes than Figma for rough thinking. Excalidraw, excalidraw.com
SVGOMG, SVG optimizer. Paste an SVG, get back a significantly smaller one with unnecessary metadata stripped. Run all your SVGs through this before shipping. SVGOMG, jakearchibald.github.io/svgomg
Most of these have been in my browser bookmarks for a while. The ones from darkmintis.dev I built because I kept needing them and couldn’t find a free version that did exactly what I wanted.
If there’s something useful missing from this list, or if you’ve found something better for any of these categories, the contact is at darkmintis.dev.