The best Hacker News stories from Show from the past week
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Show HN: Air traffic control radio and chill music for focus
Show HN: Kreuzberg – Modern async Python library for document text extraction
I'm excited to showcase Kreuzberg!<p>Kreuzberg is a modern Python library built from the ground up with async/await, type hints, and optimized I/O handling.<p>It provides a unified interface for extracting text from documents (PDFs, images, office files) without external API dependencies.<p>Key technical features:
- Built with modern Python best practices (async/await, type hints, functional-first)
- Optimized async I/O with anyio for multi-loop compatibility
- Smart worker process pool for CPU-bound tasks (OCR, doc conversion)
- Efficient batch processing with concurrent extractions
- Clean error handling with context-rich exceptions<p>I built this after struggling with existing solutions that were either synchronous-only, required complex deployments, or had poor async support. The goal was to create something that works well in modern async Python applications, can be easily dockerized or used in serverless contexts, and relies only on permissive OSS.<p>Key advantages over alternatives:
- True async support with optimized I/O
- Minimal dependencies (much smaller than alternatives)
- Perfect for serverless and async web apps
- Local processing without API calls
- Built for modern Python codebases with rigorous typing and testing<p>I Would love feedback!<p>The library is MIT licensed and open to contributions.<p>Here is the repo: <a href="https://github.com/Goldziher/kreuzberg">https://github.com/Goldziher/kreuzberg</a><p>Staring is caring
Show HN: Transform your codebase into a single Markdown doc for feeding into AI
CodeWeaver is a command-line tool designed to weave your codebase into a single, easy-to-navigate Markdown document. It recursively scans a directory, generating a structured representation of your project's file hierarchy and embedding the content of each file within code blocks. This tool simplifies codebase sharing, documentation, and integration with AI/ML code analysis tools by providing a consolidated and readable Markdown output.
Show HN: SQL Noir – Learn SQL by solving crimes
I built SQL Noir, an interactive detective game that challenges you to solve mysteries using real SQL queries. It’s fully open source, designed to give you a practical and immersive way to learn SQL while engaging with a narrative-driven mystery.
Show HN: I made my own OS from scratch because I was bored
I've wanted to make my own OS since I started programming. Now, 5 years later, I did it (kind of).<p>Sure, it is really basic, has very little functionality, but I made it and I'm proud of that. Oh, and I'm just 16 btw.
Show HN: Game Bub – open-source FPGA retro emulation handheld
Hey HN,<p>Over the past ~1.5 years, I built an open-source FPGA retro emulation handheld that can play Game Boy, Game Boy Color, and Game Boy Advance cartridges. To my knowledge, there isn't an existing open-source FPGA emulator that can play physical cartridges like this.<p>One of my main goals was to do all of the pieces myself, and be able to understand every component of it, so I designed my own PCB, wrote the firmware, wrote a Game Boy and Game Boy Advance emulator for the FPGA (using the Chisel HDL), and designed a 3D-printed case.<p>I detailed the design and development process in the linked post. It's quite long, but there are a lot of pictures and videos.<p>Code and design files available on GitHub: <a href="https://github.com/elipsitz/gamebub">https://github.com/elipsitz/gamebub</a>, and an overview of the architecture: <a href="https://github.com/elipsitz/gamebub/blob/handheld/docs/architecture.md">https://github.com/elipsitz/gamebub/blob/handheld/docs/archi...</a>
Show HN: HTML visualization of a PDF file's internal structure
Hi,
I've just finished a rebuild of this function and added a lot of new features: info, page index, minimap, inverted index,...
I think it may be useful for inspection, debugging or just as a learning resource showcasing the PDF file format.
This is a pet project and I would be happy to receive some feedback!
Regards
Show HN: FlashSpace – fast, open-source, macOS Spaces replacement
I've recently launched a new open-source project aimed at enhancing the experience of switching between Spaces/workspaces on macOS. The built-in Spaces feature is often slow and unfriendly. This project is designed to boost your productivity :). Enjoy!
Show HN: FlashSpace – fast, open-source, macOS Spaces replacement
I've recently launched a new open-source project aimed at enhancing the experience of switching between Spaces/workspaces on macOS. The built-in Spaces feature is often slow and unfriendly. This project is designed to boost your productivity :). Enjoy!
Show HN: Play with real quantum physics in your browser
I wanted to make the simplest app to introduce myself and others to quantum computing.<p>Introducing, Schrödinger's Coin. Powered by a simple Hadamard gate[0] on IBM quantum, with this app you can directly interact with a quantum system to experience true randomness.<p>Thoughts? Could you see any use cases for yourself of this? Or, does it inspire any other ideas of yours? Curious what others on HN think!<p>[0] <a href="https://en.wikipedia.org/wiki/Quantum_logic_gate#Hadamard_gate" rel="nofollow">https://en.wikipedia.org/wiki/Quantum_logic_gate#Hadamard_ga...</a>
Show HN: ExpenseOwl – Simple, self-hosted expense tracker
Show HN: ExpenseOwl – Simple, self-hosted expense tracker
Show HN: Transductive regular expressions for text editing
An extension of regular expressions for text editing, with a grep-like command-line tool. If you, like me, struggle with group logic in regular expressions, you might find it useful.<p>I wanted to do this for a very long time. It is more of a sketch or prototype. I'd really appreciate your feedback!
Show HN: A website that heatmaps your city based on your housing preferences
For the past few months, I've been working on a website that answers two different questions:<p>- Where in my city have the best travel times to all the things and people I care about?<p>- Given a listing, how far is it from all the things and people I care about?<p>Personally this was fueled by my own frustrations when I was apartment hunting in NYC. I was frustrating to have to juggle so many Google Maps tabs when I was evaluating a listing, and it was also annoying to not have full confidence that I was even searching in the right places.<p>I wanted to be close to work, a Trader Joe's, and a major park. Given that public transportation networks can sometimes make close things hard to get to and far things easy to get to, it's not always obvious whether a neighborhood actually even fits my criteria or not!<p>The overarching goal of theretowhere.com is to allow you to make more informed moving decisions while also making things more convenient than they are today.<p><a href="https://ibb.co/pBsX2HjN" rel="nofollow">https://ibb.co/pBsX2HjN</a><p>It can generate detailed travel time breakdowns for individual listings and addresses, making it easier to determine whether a listing is worth applying for without juggling Google Maps tabs.
This is great for questions like “How far is this apartment from my friends, work and dancing gyms?”<p><a href="https://ibb.co/mVBjwPrJ" rel="nofollow">https://ibb.co/mVBjwPrJ</a><p>It also has the powerful ability to heatmap a city based on which parts of it are close or not to the people and places you care about.
This is great for questions like “Where in the city would I be reasonably close to work, friends and a woodworking studio?”<p><a href="https://ibb.co/vCynPSRK" rel="nofollow">https://ibb.co/vCynPSRK</a><p>You can add these heatmaps to sites like Zillow and Streeteasy to make things super convenient (this was very fun to make).<p>The main thing that's on my mind is whether this is useful or not. Like, is this something you would actually use?
I also have other ideas I'd like to eventually intergrate into this (crime heatmaps, noise heatmaps, etc)
Show HN: An homage to Tom Dowdy's 1991 screensaver, "Kaos"
So, I was about 11 years old and just got my first Mac, a IIsi, and of course everyone had AfterDark, but there was this other screensaver program called "Dark Side of the Mac". And within it was, I think now, the most beautiful screensaver ever written. It was called Kaos.<p>Kaos would take anywhere from 10 to 30 seconds to slowly iterate on a single image, starting with a few colored dots and growing into webs within webs of algorithmic beauty.<p>I'm not sure how Tom Dowdy actually wrote the program. What I've done here is to try to reverse engineer how it might have worked, but to animate it at the same time.<p>Freezing a frame (by clicking) seems to often yield something close to the original. My method is to cycle between 1 and 30 lines, with spaced out pixels, and then iterate the whole buffer to draw fainter and fainter points within a radius from any point that's already lit, while also amplifying the ones that were lit before and shifting their colors slightly at the same time.<p>Anyway, I did this tonight but I've been thinking about it for weeks, so, I hope someone enjoys it. Cheers!
Show HN: An API that takes a URL and returns a file with browser screenshots
Show HN: SQLite disk page explorer
Show HN: I convert videos to printed flipbooks for living
I built this product back in 2018 as a small side project: a tool that turns short videos into physical flipbooks. After launching it, I didn't touch it for years. Life and work took over, and it sat idle. But it kept getting a few orders every month, which made it impossible to forget. So in December 2024, I decided to rebrand and revive it.<p>The initial version relied on various local printing offices. I kept switching from one to another, but the results were never quite right. Either the quality wasn't good enough, or the turnaround times were too long. Eventually, me and my wife bought all the necessary machines and moved production in-house.<p>Now, it's a family business. My wife and I handle everything: printing, binding, cutting, addressing, and shipping each flipbook. On the technical side, it’s powered by Next.js, with FFmpeg extracting frames and handling overlays, and ImageMagick used for adding trim marks and creating the final PDFs.<p>After many years of working in IT, working on something tangible feels refreshing. It's satisfying to create something that brings people joy. And that is not hard to sell (like dev tools, for example haha). There are still challenges: we're experimenting with different cover papers, improving production, and testing new ideas without making things confusing. But that’s part of what keeps us moving forward.
Show HN: Lume – OS lightweight CLI for MacOS and Linux VMs on Apple Silicon
We just open-sourced Lume - a tool we built after hitting walls with existing virtualization options on Apple Silicon. No GUI, no complex stacks - just a single binary that lets you spin up macOS or Linux VMs via CLI or API.<p>Why we built Lume:
- Run native macOS VMs in 1 command, using Apple Virtualization.Framework: `lume run macos-sequoia-vanilla:latest`<p>- Prebuilt images on <a href="https://ghcr.io/trycua" rel="nofollow">https://ghcr.io/trycua</a> (macOS, Ubuntu on ARM)<p>- API server to manage VMs programmatically `POST /lume/vms`<p>- A python SDK on github.com/trycua/pylume<p>Run prebuilt macOS images in just 1 step:
lume run macos-sequoia-vanilla:latest<p>How to Install:<p>brew tap trycua/lume<p>brew install lume<p>You can also download the `lume.pkg.tar.gz` archive from the latest release <a href="https://github.com/trycua/lume/releases">https://github.com/trycua/lume/releases</a>, extract it, and install the package manually.<p>Local API Server:
`lume` exposes a local HTTP API server that listens on `<a href="http://localhost:3000/lume" rel="nofollow">http://localhost:3000/lume</a>`, enabling automated management of VMs.<p>lume serve<p>For detailed API documentation, please refer to API Reference(<a href="https://github.com/trycua/lume/blob/main/docs/API-Reference.md">https://github.com/trycua/lume/blob/main/docs/API-Reference....</a>).<p>HN devs - would love raw feedback on the API design and whether this solves your Apple Silicon VM pain points. What would make you replace UTM/Multipass/Docker Desktop with this?<p>Repo: <a href="https://github.com/trycua/lume">https://github.com/trycua/lume</a>
Python SDK: github.com/trycua/pylume
Discord for direct feedback: <a href="https://discord.gg/8p56E2KJ" rel="nofollow">https://discord.gg/8p56E2KJ</a>
Show HN: Lume – OS lightweight CLI for MacOS and Linux VMs on Apple Silicon
We just open-sourced Lume - a tool we built after hitting walls with existing virtualization options on Apple Silicon. No GUI, no complex stacks - just a single binary that lets you spin up macOS or Linux VMs via CLI or API.<p>Why we built Lume:
- Run native macOS VMs in 1 command, using Apple Virtualization.Framework: `lume run macos-sequoia-vanilla:latest`<p>- Prebuilt images on <a href="https://ghcr.io/trycua" rel="nofollow">https://ghcr.io/trycua</a> (macOS, Ubuntu on ARM)<p>- API server to manage VMs programmatically `POST /lume/vms`<p>- A python SDK on github.com/trycua/pylume<p>Run prebuilt macOS images in just 1 step:
lume run macos-sequoia-vanilla:latest<p>How to Install:<p>brew tap trycua/lume<p>brew install lume<p>You can also download the `lume.pkg.tar.gz` archive from the latest release <a href="https://github.com/trycua/lume/releases">https://github.com/trycua/lume/releases</a>, extract it, and install the package manually.<p>Local API Server:
`lume` exposes a local HTTP API server that listens on `<a href="http://localhost:3000/lume" rel="nofollow">http://localhost:3000/lume</a>`, enabling automated management of VMs.<p>lume serve<p>For detailed API documentation, please refer to API Reference(<a href="https://github.com/trycua/lume/blob/main/docs/API-Reference.md">https://github.com/trycua/lume/blob/main/docs/API-Reference....</a>).<p>HN devs - would love raw feedback on the API design and whether this solves your Apple Silicon VM pain points. What would make you replace UTM/Multipass/Docker Desktop with this?<p>Repo: <a href="https://github.com/trycua/lume">https://github.com/trycua/lume</a>
Python SDK: github.com/trycua/pylume
Discord for direct feedback: <a href="https://discord.gg/8p56E2KJ" rel="nofollow">https://discord.gg/8p56E2KJ</a>