Most "developer tools" listicles are either ads or obvious. This is my actual list — websites I have open regularly and would miss if they disappeared.
1. Excalidraw (excalidraw.com)
A whiteboarding tool that produces sketchy-looking diagrams. The sketchy aesthetic is intentional — it signals "this is a rough idea" rather than "this is a finished design," which changes how people respond to it.
For system design discussions, architecture brainstorming, and explaining ideas to non-technical stakeholders, Excalidraw is the right tool. Fast, real-time collaborative, and free. No account required.
2. Regex101 (regex101.com)
You know regexes are hard to get right. Regex101 lets you write a pattern, paste test strings, and see exactly what matches and what doesn't — with a clear explanation of what each part of the pattern does.
The explanation is the killer feature. (?:https?:\/\/)?(?:www\.)? gets broken down piece by piece in plain English. You can learn regex and debug regex simultaneously.
3. tldr.sh (tldr.sh)
Man pages are exhaustive. Sometimes you just need to remember the common use of a command without reading 50 options.
tldr tar gives you the 5 most common tar use cases. tldr curl shows you the patterns you actually use, not every possible flag. Install the CLI version for offline use: npm install -g tldr.
4. jq play (jqplay.org)
Like Regex101, but for jq queries. Paste JSON, write a jq filter, see the output immediately. Indispensable when you're working with API responses or log files and need to extract specific fields.
5. Explain Shell (explainshell.com)
Paste a shell command and get each part explained. find . -type f -name "*.log" -mtime +30 -exec rm {} \; becomes comprehensible. Great for auditing commands you found on Stack Overflow before running them.
6. LGTM.sh / Conventional Comments
Not a website exactly, but the Conventional Comments standard (conventionalcomments.org) is worth knowing. It gives you a structured vocabulary for code review comments: praise:, nit:, suggestion:, issue:.
The value: reviewers communicate intent ("this is blocking" vs "this is optional") and authors know how to respond. Reduces back-and-forth significantly.
7. Carbon (carbon.now.sh)
Code snippet screenshots that don't look embarrassing. When you need to share code on Twitter/X, in slides, or in documentation and you want it to look like you made an effort.
Themeable, supports syntax highlighting for every language, and produces high-resolution images.
8. DevDocs (devdocs.io)
All the documentation, in one place, searchable, available offline. MDN, Node.js, Python, PostgreSQL, React, TypeScript — everything in a unified search interface that works without internet access.
The offline mode is the actual use case. Download the docs for whatever you're working with and search them without browser tabs, loading times, or internet dependency.
The Common Thread
None of these are particularly exciting. They're utilities that remove friction from specific tasks. That's what productivity tools actually are — friction reducers for things you do repeatedly.
The high-concept "productivity system" with elaborate workflows tends to be less useful than a small set of tools you actually reach for when you need them. This is my small set.
What's on yours? I'm genuinely curious what other developers consider load-bearing.