Show HN for July 7, 2025

Hello HN!

As a long term NYC resident, I have read countless articles on ideas tweaking subway services, but always found them hard to follow without visual aid. So over the long weekend I decided to build one. It has all the basic features: trains would spawn at their origin, stop at stations, and slow down if it gets too close to another. You can also design custom routes by piecing tracks together.

Have fun, and let me know what you think!

A Language Server Protocol (LSP) implementation for systemd unit files, providing editing support with syntax highlighting, diagnostics, autocompletion, and documentation made with rust.

I’ve always found that online calculators tend to have bad UIs, especially on mobile. Most of the calculator websites I’ve come across use outdated and inconvenient ways of inputting data, or they format the results in confusing ways.

I’ve noticed that fraction calculators (especially mixed fractions) are terrible to use, even on desktop. I haven’t built one of those yet, but it’s something I’m planning to tackle soon.

This is a project I’ve always wanted to work on, but I’m relatively new to this space. So far, I’ve created a collection of simple calculators focused on math and finance.

I’d really appreciate any feedback on the UI/UX or anything else you think could be improved.

You can try it here: https://CalculateHow.com

I built Unlearning Comparator, a visual analytics toolkit to help researchers and developers compare how different machine unlearning methods work. It provides a unified workflow to test for accuracy, efficiency, and privacy. You can check out the live demo linked in the post, and the source code is on GitHub: https://github.com/gnueaj/Machine-Unlearning-Comparator Our accompanying paper is currently under review at IEEE TVCG. Happy to answer any questions and would love to hear your feedback!

ISEVIC stands for Integrated System for Enhancing VIC output and is a cartridge for the C64 that uses the Tang Nano 20K FPGA to monitor the bus and recreate the C64 video for HDMI output. While a tremendous effort has gone into handling all the clever C64 tricks, this should be considered a 1.0 release as there are still some demos and games that exhibit bugs. Everything needed to build one is on the github page.

Hey folks, I built this as a nightly job that pulls the tweets from a burner account I made, then passes it to GPT-4.1 to summarize alongside some recent headlines: https://github.com/neelsomani/tweet-insight-daily/blob/main/...

I've been trying to make accessible and beautiful GPIO pinouts since I started one for the Raspberry Pi in 2013 [1]. I've since given the Raspberry Pi Pico [2] and Pico 2 [3] microcontrollers the same treatment when they launched.

Recently I've updated these with a new "Upside-down" view to complement the rear view, giving a pinout in the right orientation to match your project.

The Pico sites are all hand-coded single HTML pages with supporting CSS and minimal JS. They are set up to optionally install as a "Desktop" web app. They also degrade into a somewhat usable table in lieu of CSS and use vector graphics (for the board itself) to be viewable and printable at any size.

Finally, hidden behind "Advanced" is a pinout of the test pads and special function pins!

[1] - https://web.archive.org/web/20130505194305/pi.gadgetoid.com/... [2] - https://pico.pinout.xyz [3] - https://pico2.pinout.xyz

I built Whispering because I believe transcription is too fundamental a tool to be locked behind paywalls. It's a cross-platform desktop and web transcription app that turns speech into text with a keyboard shortcut, among other things.

The app lets you bring your own API key (OpenAI, Groq, etc.) and make direct calls. If you want complete privacy, it also supports local transcription. Either way, your audio never goes through any middleman servers. It's super lightweight (~22MB), built with Svelte 5 and Tauri, and works on Mac, Windows, and Linux.

I've been using it daily for the past few months and just released v7 last night. I spent a considerable amount of time developing a clean architecture that's hopefully educational to read. This is one of the most complex Svelte 5 apps in production, with extensive use of runes and TanStack Query.

I'm happy to answer questions about implementation or how to build desktop apps with this stack!

Geofenced reminders are great, but quite a hassle to set up in iOS.

Remind There simplifies and makes it more fun to use geofenced reminders on iOS!

Hello HN!

As a EM, I recently asked for a "good" handoff doc to my engineers who're leaving, but without proper structure, the first draft was pretty crappy. Studying and thinking hard about what readers(i.e., me) might want on header level and what would be a good representation in each section, we came up with a good template for handoff doc. The result was fantastic. I think we all can write better with a proper format and template. That is where I came up with this idea, doc81.

Have fun, and let me know what you think!

Hey HN! Yoink AI a macOS app that grabs context from any text field (Word, Gmail, Notion, Slack, etc.), rewrites or generates conten in place, and pastes it back. No copy/paste loops or AI rambling. Just select text, hit Cmd+Shift+Y, and it seamlessly edits or replaces directly in your workflow.

The goal is speed and tight control for users frustrated by slow, verbose AI tools. Would love feedback on the UX and output quality.

Try it at useyoink.ai.

2-factor authentication terrorizes me.

Many years ago, I was at a friend's house and decided to quickly pop downstairs to buy something.

When trying to re-enter the building, the main gate had locked. And since my phone, keys, and any spare cash were all left upstairs, I was stuck outside.

Thankfully, Google, at the time, allowed users to send SMSes (SMSs?) through the Hangouts app, which I did after logging into my account from an internet cafe. (Back then people weren’t constantly connected to Facebook, etc.)

Since that day I feared being locked out of my accounts by 2FA, simply because my phone (and my access codes) weren't with me.

And while it's true that today people are always connected to messaging apps, I wouldn't be able to reach any of them without me being able to log into mine.

That’s why I built life_link, an app that allows my loved ones to reach me, wherever they are, without having to care about 2FA or even needing to log in. To do so, they simply need to reach the app on a secret (short) URL.

I've since expanded life_link by creating a "generator" app that can produce a pre-configured, single-file application, ready to be deployed on any static site hosting service and decided to open-source it for other people who might find it useful.

You can find the life_link project and learn more about it here:

https://github.com/ahmedsaoudi/life_link

I built a free validator for llms.txt and llms-full.txt files.

Paste your content or check a live URL. Shows errors like missing headers, malformed links, or duplicates.

"Bye 'For You' " is a browser extension that removes the algorithmic X 'For you' evil tab, it defaults to the "Following" tab instead so you can now follow only who you actually follow without the noise and zombie scroll. It is available both on the Chrome and Mozilla Web Stores to download and it's Open Source so you are free to contribute by adding more languages if you want :)

Article: https://github.com/theotrama/dns-resolver/blob/main/article/... Deployed version: https://domain-name-resolver.fly.dev

I've been thinking about ways to improve emotional self-awareness without relying on mood logs, which often feel forced or artificial. Instead of asking "how are you feeling?", what if we looked at what someone did during the day — and derived their emotional state from that?

I tried implementing this using a BERT-based model trained on Google’s GoEmotions dataset (which covers 28 nuanced emotions like remorse, joy, optimism, etc.). The idea is to let users reflect on their good or bad deeds, and then use NLP to classify the underlying emotions.

Some patterns I’ve noticed:

Visualizing daily dominant emotions on a color-coded calendar gives a quick emotional overview.

Comparing emotions across days offers insights into how our actions shape our emotional trends.

Action-first reflection seems to reduce the pressure to “perform” emotionally compared to mood logs.

This is all part of an Android experiment I’m working on. Curious if others here have explored similar approaches — using AI to model emotion based on actions rather than self-reporting. Would love to hear your thoughts or feedback.

If you're curious about the implementation or want to see what the Android experiment looks like in action, I wrote more about it here:

https://medium.com/@va6042/what-if-your-daily-actions-could-...

Feedback — technical, UX, or philosophical — is very welcome.

Any feedback is appreciated!

I built Error Narrator — a Python tool that explains exceptions in plain English (and Russian, too).

It goes beyond just showing the traceback. It tells you: – What happened (in human terms) – Why it happened (including the concept behind the error) – Where exactly it happened (file + line) – How to fix it (with code suggestions)

It works with OpenAI or HuggingFace models and runs directly in your terminal or scripts.

This tool helped me save time and also helped friends who are just learning Python. I'd love your feedback, suggestions, or even contributions. It’s open source.

Hi HN!

I've built [CXXStateTree](https://github.com/ZigRazor/CXXStateTree), a modern C++ header-only library to create hierarchical state machines with clean, intuitive APIs.

It supports: - Deeply nested states - Entry/exit handlers - State transitions with guards and actions - Asynchronous transitions with `co_await` (C++20 coroutines) - Optional runtime type identification for flexibility

It's ideal for complex control logic, embedded systems, games, robotics, and anywhere you'd use a finite state machine.

I’d love feedback, use cases, or contributions from the community!

Repo: https://github.com/ZigRazor/CXXStateTree

Hey, Hello, we are the team behind NobodyWho; an open-source plugin that embeds large language models functionality inside Unity and Godot games - completely locally and offline.

We try to make it as easy and user friendly as possible to use our plugin, so feel free to create an issue on our GitHub if you have any inconveniences - and we will try to improve it!

So why might this interest you:

- Written in Rust with llama.cpp bindings and optional GPU back-ends (Vulkan / Metal) for fast inference.

- Drop-in nodes / components: add a model asset and a chat or embedding node and get a working prototype almost instantly.

- Tool calling – register C#/GDScript methods and let the model invoke them at runtime.

- Grammar-constrained output – force output to be valid JSON or custom grammar.

- Automatic context shifting & streaming – handles long dialogues by shifting the context and streams tokens.

- Embeddings API – similarity search and comparisons.

- Cross-platform binaries for Windows, Linux, macOS.

- Permissive EUPL-1.2 licence (free for commercial games, only plugin forks must remain open).

Quick start

- GitHub repo & docs: https://github.com/nobodywho-ooo/nobodywho

- Unity & Godot packages in the releases section (Asset Store submission for tool calling in Unity is still pending).

We built NobodyWho to enable richer, privacy-friendly AI gameplay without server bills. Feedback, issues, and PRs are welcome and if it helps your project, a star makes discovery easier.

Cheers!

— NobodyWho team