The best Hacker News stories from Show from the past week
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Show HN: Steal My Bitcoin
Made this because I'm curious if anyone out there has figured out how to actually use this PHP RCE we spent the last few days panicking over. Have fun!
Show HN: OnKey – I'm a bad singer, so I built an app to show where I'm off-key
Hi all<p>I was pretty terrible at singing, now I’d say I’m bad but not terrible. This is because I’ve been using a singing app (won’t name it here) that scores me on my pitch and timing throughout the song so that I can improve.<p>Lately however, the app I’ve been using has flooded their song list with songs that aren’t originals. I didn’t like this at all as for me, it’s easier to try to improve when you’re singing along to the original.<p>So, I asked an agent (Claude Code) if it could write some code to listen to Spotify and also listen to me and see if it could detect both pitches and score me. It impressed me by writing some Python and showing me my pitch in the terminal!<p>It couldn’t go all the way though and detect the singer’s pitch in real time.<p>So I found the next best setup and built OnKey, a Mac app that needs to listen to the song once (it doesn’t save it) and then when it’s learnt the song (takes a couple of minutes), you can sing along to the pitch track that it’s learnt. OnKey is free to use and open source under the MIT license.<p>It can listen to Spotify, Apple Music, and YouTube playing in your browser with the right permissions.<p>During the build I found that someone had done something similar in Nightingale, but this requires a library of songs exported to disk and who has this in 2026 (maybe some of you ;) - but we need to help the normies too).<p>You can check out a demo video on the site of me singing (warning given) here: <a href="https://singonkey.app" rel="nofollow">https://singonkey.app</a><p>The app sends out to find the song info (short Shazam fingerprint, and looks up song details), lyrics (from LRCLIB), and checks for updates.<p>The app never sends the music (it doesn’t save this to disk) and your voice. Everything you’d expect to stay private does.<p>It’s still weak in a few places:<p>- when the song’s backing is noisy it’s hard to pick the pitch track out<p>- sometimes it gets a note an octave off<p>- it’s limited to Apple Silicon Macs, M1 or later, and only macOS 14.2 up because extra drivers aren’t required past this point<p>- the scoring is built for beginners like me so it’s fairly easy on you<p>Would love for people to try it out and let me know what works and what doesn’t for them!
Run full iOS 16.5 firmware on Android Devices
<a href="https://hackios-web.vercel.app/en" rel="nofollow">https://hackios-web.vercel.app/en</a>
Show HN: SimCity, but with Permits
Show HN: Qwen3-4B with the AI writing tics trained out
Show HN: WhatsApp MCP running free on Cloudflare
I wanted my humble Claude on mobile to access my WhatsApp messages but the only options I could find either required WhatsApp Business or an actual server to run Baileys on.<p>I wanted to run it for free on ClaudeFlare and with my personal WhatsApp account, so I built this.<p>Important feature - it connects to your Google account as well as WhatsApp to grab the names of all your WhatsApp contacts, otherwise you get only phone numbers for many of them and search doesn't work properly.<p>This is a single user install because it's both gray area and very private - so point your agent at the repo and let it set things up.
Show HN: The Zelda timeline to catch up before the Ocarina of Time remake
I made this ahead of the Ocarina of Time remake which comes out in 17 days. I remember the feeling of playing it as a kid but I hadn’t kept up with the story so I built a timeline to catch up before the Door of Time reopens.<p>Nintendo’s own timeline is the authority here (Hyrule Historia and their chronicle page). The fun part was rethinking how to visualize it. It branches at the end of Ocarina into three eras depending on whether Link wins or loses, so each era is its own thread on the cloth. The threads meet again much later with Breath of the Wild.<p>I had a lot of help from Claude. I’d often thought about building things like this but never found the time between the day job and the rest of life.
Show HN: Sphinx – A hook that quizzes you on your AI's code before shipping
FOSS, Basically it plugs into your existing coding agent workflow and every time you push to prod it'll throw up a questionnaire that checks if you understand how the code you're pushing works.
Show HN: Sphinx – A hook that quizzes you on your AI's code before shipping
FOSS, Basically it plugs into your existing coding agent workflow and every time you push to prod it'll throw up a questionnaire that checks if you understand how the code you're pushing works.
Show HN: High-quality duck audio synthesizer
Show HN: Esp32sim – Run ESP32 firmware in the browser
Hi HN,<p>I’ve been working on esp32sim, an open-source ESP32 emulator that runs in the browser.<p>The fun part of the demo is that there is no ESP32 involved — the firmware is executing in the emulator.<p>The goal is to make ESP32 software easier to experiment with, test and simulate without always needing physical hardware connected.<p>Source:
<a href="https://github.com/mikroverk/esp32sim" rel="nofollow">https://github.com/mikroverk/esp32sim</a><p>I made a short video showing it in action:
<a href="https://youtu.be/waoWFilTWEc" rel="nofollow">https://youtu.be/waoWFilTWEc</a><p>I’m particularly interested in feedback from embedded developers: what would an emulator like this need to support before you’d actually use it for development, testing or CI?
Show HN: Llmspeed – feel how fast a local LLM runs before you buy the hardware
Show HN: Gemini 4 Argon plays StarCraft
I've refreshed StarSkirmish Bench, a benchmark where LLMs play StarCraft BW by writing code, with results from the flagship models of OpenAI, Anthropic, Google, and Muse
Show HN: Unfenced – Land for sale that borders public land
Show HN: Petal, open-source CoScreen/ScreenHero finally free
Hi HN!<p>I’m Jason Thomas, one of the founders of CoScreen.<p>As some of you may know, Datadog sunset the CoScreen service on July 31st.<p>Four of us from the original CoScreen team have spent the last couple months building a free and open source pair programming tool inspired by those that came before us: It’s called Petal (<a href="https://github.com/kiruna-labs/petal" rel="nofollow">https://github.com/kiruna-labs/petal</a>)<p>Some history first, because when we started CoScreen we had hoped to break the sad and established pattern of this industry.<p>Screenhero was an exceptional tool that a lot of us loved for pairing. Multiple cursors, low latency, you could click your partner’s editor, and just start typing. It felt like magic while we had it. Then Slack bought it in 2015, and shut down the standalone app in December 2017.<p>When Till, Max, and I started CoScreen, we were aware of this history, and wanted to build an even more magical collaboration and screen sharing experience: the entire concept was “throw a window from your laptop up on someone else’s screen, and start collaborating with zero friction.”<p>Datadog acquired us in 2022, and thus began the great adventure of adapting our real-time technology into Datadog products, while also continue developing CoScreen as a standalone tool from the Datadog ecosystem. Datadog invested in the product for years and we’re thankful for that. But CoScreen itself proved, like so many other screen sharing tool acquisitions, to be too tangential from the customer base and core mission. We instead built other communication features in Datadog, the integrations with other video platforms, and also its wildly successful MCP server.
We weren't the only ones. Around was bought by Miro and shut down in March 2025. Multi (formerly Remotion) was acqui-hired by OpenAI in 2024 and shut down about a month later. It's nearly always the same story: a small team builds something hard that people love, a platform buys it for the team or the feature, and the standalone product doesn't survive the integration.
So we decided firmly to do things differently this time. Petal is completely free and open source and we aren't monetizing it. If we lose interest or get hit by a bus, you can self-host it or fork it, and nobody can sunset it on you. Honestly it's a love letter to everyone in this community that supported us, believed in us, and to liberate collaborative screen sharing from this vicious cycle.<p>We hope through this we can help foster a large and vibrant community around innovating in this product sector.
What Petal does: shared windows show up as real windows on your desktop, movable and resizable, not tiles in a grid. Several people can share at once, everyone gets a labeled cursor, and you can click into any shared window to type and scroll. Rooms are persistent, so you click once to join "eng-sync" instead of passing links around.
It runs on macOS and Windows (Linux is next, this time for real and you can help us!), plus a web app. Media goes over LiveKit. You can use our hosted instance with zero config, or point the app at your own LiveKit server with one docker-compose if you want the traffic to stay on your network or even use an entirely different video backend if you want to.
The part that still feels strange to us: CoScreen took almost six years to build. The first version of Petal took under eight weeks, from scratch, with frontier models like Fable and Astra doing a lot of the work. Real-time video and window capture is some of the most unforgiving code we have ever written, so we didn't expect that. We will do a proper writeup on what worked and what didn't, and are happy to answer questions about it here.
Till, Darren, Max and I will be in the thread.
Show HN: How random are you?
Show HN: Use your OpenAI subscription to create audiobooks
Show HN: Guitoro, a virtual guitar you strum with your keyboard
Guitoro is a free browser guitar using recordings of real instruments. You can strum with your keyboard, mouse, or touchscreen, choose acoustic, classical, electric guitar or bass, and see chord fingering and each stroke. Song practice can be slowed to 20%, and there are free chord tools and tuners. No signup or download.<p>1 minute video demo: <a href="https://youtu.be/DtcluMLdSgs" rel="nofollow">https://youtu.be/DtcluMLdSgs</a><p>I would love feedback on how the strumming feels and sounds.
Show HN: PS2 games statically recompiled to WebAssembly
Show HN: BetterWispr – Free, open-source dictation for Mac