The best Hacker News stories from Show from the past day
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Show HN: EuConform – Offline-first EU AI Act compliance tool (open source)
I built this as a personal open-source project to explore how EU AI Act
requirements can be translated into concrete, inspectable technical checks.<p>The core idea is local-first compliance:
– risk classification (Articles 5–15, incl. prohibited use cases)
– bias evaluation using CrowS-Pairs
– automatic Annex IV–oriented PDF reports
– no cloud services or external APIs (browser-based + Ollama)<p>I’m especially interested in feedback on whether this kind of
technical framing of AI regulation makes sense in real-world projects.
Show HN: Rocket Launch and Orbit Simulator
I (17y/o) have been developing a rocket launch simulation that allows the user to explore what it's like launching a rocket from earth and putting it into orbit. This idea originally started as an educational simulation but as i've gone more down the rabbit hole the more i've wanted to make it realistic. The problem is that I've never had a formal orbital mechanics class or anything like that so I don't know what I'm missing, what I currently have implemented is:<p><pre><code> Variable gravity
Variable Atmospheric drag (US Standard Atmosphere 1976)
Multi-stage rockets
Closed-loop guidance / pitch programs (works well within ranges 350km to 600km)
Orbital prediction and thrusting options to change your orbit.
</code></pre>
The feedback I'm looking for is: UI improvements and possible future physics implementations that I can work on.<p>Current code and physics can be found at: <a href="https://github.com/donutTheJedi/Rocket-Launch-Simulation" rel="nofollow">https://github.com/donutTheJedi/Rocket-Launch-Simulation</a>
Show HN: Similarity = cosine(your_GitHub_stars, Karpathy) Client-side
GitHub profile analysis
- Build your embedding from your Stars
- Compare and discover popular people with similar interests and share yours
- Generate a Skill Radar
- Recommend repositories you might like
Show HN: Executable Markdown files with Unix pipes
I wanted to run markdown files like shell scripts. So I built an open source tool that lets you use a shebang to pipe them through Claude Code with full stdin/stdout support.<p>task.md:<p><pre><code> #!/usr/bin/env claude-run
Analyze this codebase and summarize the architecture.
</code></pre>
Then:<p><pre><code> chmod +x task.md
./task.md
</code></pre>
These aren't just prompts. Claude Code has tool use, so a markdown file can run shell commands, write scripts, read files, make API calls. The prompt orchestrates everything.<p>A script that runs your tests and reports results (`run_tests.md`):<p><pre><code> #!/usr/bin/env claude-run --permission-mode bypassPermissions
Run ./test/run_tests.sh and summarize what passed and failed.
</code></pre>
Because stdin/stdout work like any Unix program, you can chain them:<p><pre><code> cat data.json | ./analyze.md > results.txt
git log -10 | ./summarize.md
./generate.md | ./review.md > final.txt
</code></pre>
Or mix them with traditional shell scripts:<p><pre><code> for f in logs/\*.txt; do
cat "$f" | ./analyze.md >> summary.txt
done
</code></pre>
This replaced a lot of Python glue code for us. Tasks that needed LLM orchestration libraries are now markdown files composed with standard Unix tools. Composable as building blocks, runnable as cron jobs, etc.<p>One thing we didn't expect is that these are more auditable (and shareable) than shell scripts. Install scripts like `curl -fsSL <a href="https://bun.com/install" rel="nofollow">https://bun.com/install</a> | bash` could become:<p><pre><code> `curl -fsSL https://bun.com/install.md | claude-run`
</code></pre>
Where install.md says something like "Detect my OS and architecture, download the right binary from GitHub releases, extract to ~/.local/bin, update my shell config." A normal human can actually read and verify that.<p>The (really cool) executable markdown idea and auditability examples are from Pete Koomen (@koomen on X). As Pete says: "Markdown feels increasingly important in a way I'm not sure most people have wrapped their heads around yet."<p>We implemented it and added Unix pipe semantics. Currently works with Claude Code - hoping to support other AI coding tools too. You can also route scripts through different cloud providers (AWS Bedrock, etc.) if you want separate billing for automated jobs.<p>GitHub: <a href="https://github.com/andisearch/claude-switcher" rel="nofollow">https://github.com/andisearch/claude-switcher</a><p>What workflows would you use this for?
Show HN: Scroll Wikipedia like TikTok
Hey - I've been playing with LLMs since GPT-2 and recently experimented with fully generative UIs where the HTML/Canvas are generated just-in-time.<p>Every post on the feed( on slop/duck/storytime) you see is streamed and generated just-in-time with HTML and into a Canvas with Gemini 3 Flash.<p>Comments and DMs are bidirectionally linked with a Cloudflare Workers Durable Object which is why they feel so fast. Every generated post is saved into a DO SQLite which is then served into the "Following" feed so it can be served quicker.<p>This was inspired by Wikitok, a VSCode Extension I made around brainrot, and another fully generative UI site I made.
Show HN: I made a memory game to teach you to play piano by ear
Show HN: Comet MCP – Give Claude Code a browser that can click
Hey HN,<p>Claude Code is pretty agentic now. It writes scripts, calls APIs, uses CLIs. But when something requires actually clicking through a website, it stops and asks me to do it.<p>Problem is, I'm often unfamiliar with these platforms myself. "Go to App Store Connect and generate a P8 key" okay but where? I end up spending 10 minutes navigating menus I've never seen before.<p>I started delegating these tasks to Perplexity's Comet browser. It handles the clicking, returns what I need. But copy-pasting between Claude and Comet got old fast.<p>So I built this MCP server to connect them directly. Now when Claude needs to interact with a website that has no API, it can just ask Comet to handle it.<p><pre><code> Examples:
- Grab my app ID from RevenueCat dashboard
- Generate a P8 key in App Store Connect
- Navigate admin panels behind login walls
</code></pre>
I tried Playwright MCP but having Claude do the clicking itself overwhelms the context window. Comet's agentic browsing just works better in my experience.<p>Comet doesn't have an API, so this uses CDP to communicate with it directly.
Show HN: Free and local browser tool for designing gear models for 3D printing
Just build a local tool for designing gears that kinda looks and works nice
Show HN: DeepDream for Video with Temporal Consistency
I forked a PyTorch DeepDream implementation and added video support with temporal consistency. It produces smooth DeepDream videos with minimal flickering, and is highly flexible including many parameters and supports multiple pretrained image classifiers including GoogLeNet. Check out the repo for sample videos!
Features:<p>- Optical flow warps previous hallucinations into the current frame<p>- Occlusion masking prevents ghosting and hallucination transfer when objects move<p>- Advanced parameters (layers, octaves, iterations) still work<p>- Works on GPU, CPU, and Apple Silicon
Show HN: A geofence-based social network app 6 years in development
My name is Adrian. I'm a Software Engineer and I spent 6 years developing a perimeter-based geofence-based social media app.<p>What it does:<p>- Allows you to load a custom perimeter anywhere on the geographic map (180° E and W longitude and 90° N and S latitude), to cover area any area of interest<p>- Chat rooms get loaded within the perimeter<p>- You can chat with people within the perimeter<p>I developed a mobile app that uses an advanced geofence-based networking system from 2013 to 2019. My goal was to connect users within polygon geofences anywhere in the world. The app is capable of loading millions of polygon geofences anywhere in the world.<p><a href="https://enterpriseandroidfoundation.com/assets/images/other/manhattan-polygon-geofences.png" rel="nofollow">https://enterpriseandroidfoundation.com/assets/images/other/...</a><p>But people didn't really have a need for this. So after failing, I spent the next 6 years trying new ideas to use FencedIn for. I tried a location-based video app and a place-based app that had multiple features. Nothing worked, but now I'm almost finished developing ChatLocal, an app that allows you to load a perimeter anywhere on the geographic map, which loads chat rooms.<p>The tech stack is 100% Java (low-level mostly). I have a backend, commons library and an Android app. Java was the natural choice back in 2013. However, I still wouldn't choose anything else today. Java is the best for long-term large-scale projects. (I'm also using WildFly. PostgreSQL and a Linux server.)<p>This app is still not fully finished, but I think the impact on society might be tremendous.<p>The previous app to ChatLocal, LocalVideo, is fully up on the Google Play store and can be tested. It has 88% of the features of ChatLocal, including especially the perimeter-based loading system.<p>The feedback I'm mostly looking for is new ideas and concepts to add to this location-based social media app. And how strong of a value proposition does the app have for society.
Show HN: A geofence-based social network app 6 years in development
My name is Adrian. I'm a Software Engineer and I spent 6 years developing a perimeter-based geofence-based social media app.<p>What it does:<p>- Allows you to load a custom perimeter anywhere on the geographic map (180° E and W longitude and 90° N and S latitude), to cover area any area of interest<p>- Chat rooms get loaded within the perimeter<p>- You can chat with people within the perimeter<p>I developed a mobile app that uses an advanced geofence-based networking system from 2013 to 2019. My goal was to connect users within polygon geofences anywhere in the world. The app is capable of loading millions of polygon geofences anywhere in the world.<p><a href="https://enterpriseandroidfoundation.com/assets/images/other/manhattan-polygon-geofences.png" rel="nofollow">https://enterpriseandroidfoundation.com/assets/images/other/...</a><p>But people didn't really have a need for this. So after failing, I spent the next 6 years trying new ideas to use FencedIn for. I tried a location-based video app and a place-based app that had multiple features. Nothing worked, but now I'm almost finished developing ChatLocal, an app that allows you to load a perimeter anywhere on the geographic map, which loads chat rooms.<p>The tech stack is 100% Java (low-level mostly). I have a backend, commons library and an Android app. Java was the natural choice back in 2013. However, I still wouldn't choose anything else today. Java is the best for long-term large-scale projects. (I'm also using WildFly. PostgreSQL and a Linux server.)<p>This app is still not fully finished, but I think the impact on society might be tremendous.<p>The previous app to ChatLocal, LocalVideo, is fully up on the Google Play store and can be tested. It has 88% of the features of ChatLocal, including especially the perimeter-based loading system.<p>The feedback I'm mostly looking for is new ideas and concepts to add to this location-based social media app. And how strong of a value proposition does the app have for society.
Show HN: A Daily Bible Game
I created a daily game where you get a random Bible verse and try to identify the book (e.g. "Psalms", "Genesis", "Luke") in as few guesses as possible.<p>I have absolutely no clue how I got the idea, other than the fact that I grew up in the Orthodox Church and all my other coding projects have been faith-related (a terrible mobile app (1) and slightly broken Byzantine chant website (2) ). I'm a relatively new developer and I've been hungry for a project to build that people will actually use and share around, so I hoped this would fit the bill.<p>Sure enough, friends and family have been making it part of their daily routine. When priests AND my nonreligious college friends started sending me their results every day, I knew I had <i>something</i>. It was really exciting.<p>------<p>When the idea popped into my head, I started working on it right away. I created the project at 1AM and had a MVP/SLC version done a few hours later. That was a few weeks ago.<p>I am using SvelteKit, no external APIs, and SQLite for the database. It's hosted on an Ubuntu machine in my living room. Coding agents like Roo/Kilo Code assisted heavily in the development, but after I had already decided on the overall architecture and how I wanted things to work together.<p>The game is free, has no signup, and I’m not running any ads. I’m looking for any and all feedback, and especially suggestions for how I can make the game more interesting, fun, and/or educational.<p>Thank you HN!
Show HN: macOS menu bar app to track Claude usage in real time
I built a macOS menu bar app to track Claude usage in real time via API after hitting limits mid-flow too often.<p>Signed and notarised by Apple. Open source.<p><a href="https://github.com/richhickson/claudecodeusage" rel="nofollow">https://github.com/richhickson/claudecodeusage</a><p><a href="https://x.com/richhickson" rel="nofollow">https://x.com/richhickson</a>
Show HN: macOS menu bar app to track Claude usage in real time
I built a macOS menu bar app to track Claude usage in real time via API after hitting limits mid-flow too often.<p>Signed and notarised by Apple. Open source.<p><a href="https://github.com/richhickson/claudecodeusage" rel="nofollow">https://github.com/richhickson/claudecodeusage</a><p><a href="https://x.com/richhickson" rel="nofollow">https://x.com/richhickson</a>
Show HN: VaultSandbox – Test your real MailGun/SES/etc. integration
I've spent the last few months working on something I wish I'd had years ago.
I kept running into the same issue: CI green, production mail broken. TLS handshake failures, DKIM alignment mismatches, SPF soft-fails ... the stuff that only surfaces when real mail servers are involved.
Most test tools (Mailpit, MailHog) are catch-alls. They confirm "an email was sent" but don't validate the protocol. They also aren't designed for network-exposed environments: no auth, unprotected Web UI, easy to enumerate messages.<p>VaultSandbox is my attempt at fixing that.
It's a self-hosted SMTP gateway (AGPLv3) that validates SPF, DKIM, DMARC, and rDNS on every incoming message. You keep your production email provider (Postmark, SendGrid, SES) in tests and you just change the recipient domain. No mocking, no config changes.
There are client SDKs (Node, Python, Go, Java, .NET), plus a Web UI and a CLI for manual testing.<p>Some technical details:<p>Deterministic Tests
Instead of polling or sleep loops, the SDKs use Server-Sent Events (SSE) so test assertions trigger the moment the mail hits the gateway.<p>Minimal infrastructure footprint
Built with NestJS and Angular, with no external database dependency to keep the container footprint small and easier to reason about.<p>Post-Quantum Encryption
I use ML-KEM-768 for the encryption layer. Incoming mail is encrypted immediately using a client-generated public key and the plaintext is discarded. The server only ever stores encrypted message data and cannot decrypt it. I chose PQ because I wanted to build something I wouldn't have to revisit in five years. If it handles large PQ keys reliably, everything else is easy.<p>Quick start:
<a href="https://vaultsandbox.dev/getting-started/quickstart/" rel="nofollow">https://vaultsandbox.dev/getting-started/quickstart/</a><p>Site:
<a href="https://vaultsandbox.com" rel="nofollow">https://vaultsandbox.com</a><p>I'd love feedback, especially on whether AGPLv3 would be a blocker for something you'd self-host in dev.
Show HN: VaultSandbox – Test your real MailGun/SES/etc. integration
I've spent the last few months working on something I wish I'd had years ago.
I kept running into the same issue: CI green, production mail broken. TLS handshake failures, DKIM alignment mismatches, SPF soft-fails ... the stuff that only surfaces when real mail servers are involved.
Most test tools (Mailpit, MailHog) are catch-alls. They confirm "an email was sent" but don't validate the protocol. They also aren't designed for network-exposed environments: no auth, unprotected Web UI, easy to enumerate messages.<p>VaultSandbox is my attempt at fixing that.
It's a self-hosted SMTP gateway (AGPLv3) that validates SPF, DKIM, DMARC, and rDNS on every incoming message. You keep your production email provider (Postmark, SendGrid, SES) in tests and you just change the recipient domain. No mocking, no config changes.
There are client SDKs (Node, Python, Go, Java, .NET), plus a Web UI and a CLI for manual testing.<p>Some technical details:<p>Deterministic Tests
Instead of polling or sleep loops, the SDKs use Server-Sent Events (SSE) so test assertions trigger the moment the mail hits the gateway.<p>Minimal infrastructure footprint
Built with NestJS and Angular, with no external database dependency to keep the container footprint small and easier to reason about.<p>Post-Quantum Encryption
I use ML-KEM-768 for the encryption layer. Incoming mail is encrypted immediately using a client-generated public key and the plaintext is discarded. The server only ever stores encrypted message data and cannot decrypt it. I chose PQ because I wanted to build something I wouldn't have to revisit in five years. If it handles large PQ keys reliably, everything else is easy.<p>Quick start:
<a href="https://vaultsandbox.dev/getting-started/quickstart/" rel="nofollow">https://vaultsandbox.dev/getting-started/quickstart/</a><p>Site:
<a href="https://vaultsandbox.com" rel="nofollow">https://vaultsandbox.com</a><p>I'd love feedback, especially on whether AGPLv3 would be a blocker for something you'd self-host in dev.
Show HN: Make audio loops online
I created a small webapp, to create simple audio loops online. A bit rough around the edges but gets you started in less than 10 seconds on creating loops.
Show HN: Stash – Sync Markdown Files with Apple Notes via CLI
Show HN: I visualized the entire history of Citi Bike in the browser
Each moving arrow represents one real bike ride out of 291 million, and if you've ever taken a Citi Bike before, you are included in this massive visualization!<p>You can search for your ride using Cmd + K and your Citi Bike receipt, which should give you the time of your ride and start/end station.<p>Everything is open source: <a href="https://github.com/freemanjiang/bikemap" rel="nofollow">https://github.com/freemanjiang/bikemap</a><p>Some technical details:
- No backend! Processed data is stored in parquet files on a Cloudflare CDN, and queried directly by DuckDB WASM<p>- deck.gl w/ Mapbox for GPU-accelerated rendering of thousands of concurrent animated bikes<p>- Web Workers decode polyline routes and do as much precomputation as possible off the main thread<p>- Since only (start, end) station pairs are provided, routes are generated by querying OSRM for the shortest path between all 2,400+ station pairs
Show HN: I visualized the entire history of Citi Bike in the browser
Each moving arrow represents one real bike ride out of 291 million, and if you've ever taken a Citi Bike before, you are included in this massive visualization!<p>You can search for your ride using Cmd + K and your Citi Bike receipt, which should give you the time of your ride and start/end station.<p>Everything is open source: <a href="https://github.com/freemanjiang/bikemap" rel="nofollow">https://github.com/freemanjiang/bikemap</a><p>Some technical details:
- No backend! Processed data is stored in parquet files on a Cloudflare CDN, and queried directly by DuckDB WASM<p>- deck.gl w/ Mapbox for GPU-accelerated rendering of thousands of concurrent animated bikes<p>- Web Workers decode polyline routes and do as much precomputation as possible off the main thread<p>- Since only (start, end) station pairs are provided, routes are generated by querying OSRM for the shortest path between all 2,400+ station pairs