The best Hacker News stories from Show from the past day
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Show HN: Faceoff – A terminal UI for following NHL games
Faceoff is a TUI app written in Python to follow live NHL games and browse standings and stats. I got the inspiration from Playball, a similar TUI app for MLB games that was featured on HN.<p>The app was mostly vibe-coded with Claude Code, but not one-shot. I added features and fixed bugs by using it, as I spent way too much time in the terminal over the last few months.<p>Try it out with `uvx faceoff` (requires uv).
Show HN: Prompt-to-Excalidraw demo with Gemma 4 E2B in the browser (3.1GB)
Show HN: Shader Lab, like Photoshop but for shaders
Show HN: AI Subroutines – Run automation scripts inside your browser tab
We built AI Subroutines in rtrvr.ai. Record a browser task once, save it as a callable tool, replay it at: zero token cost, zero LLM inference delay, and zero mistakes.<p>The subroutine itself is a deterministic script composed of discovered network calls hitting the site's backend as well as page interactions like click/type/find.<p>The key architectural decision: the script executes inside the webpage itself, not through a proxy, not in a headless worker, not out of process. The script dispatches requests from the tab's execution context, so auth, CSRF, TLS session, and signed headers get added to all requests and propagate for free. No certificate installation, no TLS fingerprint modification, no separate auth stack to maintain.<p>During recording, the extension intercepts network requests (MAIN-world fetch/XHR patch + webRequest fallback). We score and trim ~300 requests down to ~5 based on method, timing relative to DOM events, and origin. Volatile GraphQL operation IDs are detected and force a DOM-only fallback before they break silently on the next run.<p>The generated code combines network calls with DOM actions (click, type, find) in the same function via an rtrvr.* helper namespace. Point the agent at a spreadsheet of 500 rows and with just one LLM call parameters are assigned and 500 Subroutines kicked off.<p>Key use cases:<p>- record sending IG DM, then have reusable and callable routine to send DMs at zero token cost<p>- create routine getting latest products in site catalog, call it to get thousands of products via direct graphql queries<p>- setup routine to file EHR form based on parameters to the tool, AI infers parameters from current page context and calls tool<p>- reuse routine daily to sync outbound messages on LinkedIn/Slack/Gmail to a CRM using a MCP server<p>We see the fundamental reason that browser agents haven't taken off is that for repetitive tasks going through the inference loop is unnecessary. Better to just record once, and get the LLM to generate a script leveraging all the possible ways to interact with a site and the wider web like directly calling backed API's, interacting with the DOM, and calling 3P tools/APIs/MCP servers.
Show HN: MDV – a Markdown superset for docs, dashboards, and slides with data
Show HN: MDV – a Markdown superset for docs, dashboards, and slides with data
Show HN: I made a calculator that works over disjoint sets of intervals
I've been studying interval arithmetic for the past few weeks and it's a really interesting field because while there is a ton of super interesting research published over the past decades, it has never really gotten the recognition that it deserves, IMO.<p>One reason for this is that standard interval arithmetic has really poor handling of division by intervals containing zero. If you compute 1 / [-1, 2] in regular interval arithmetic, you get either [-∞, +∞], or you have to say that the operation is undefined. Both solutions are virtually useless. The real answer of course is [-∞, -1] U [0.5, +∞]: i.e. a union of two disjoint intervals.<p>This is useful because you can confidently exclude a non empty set of the real numbers ([-1, 0.5]) from the set of possible values that you can get by dividing 1 by a number between -1 and 2.<p>But this definition of interval division yields a value that is not an interval. This is a problem if you want to define a closed arithmetic system, where you can build and evaluate arbitrary expression over interval values.<p>(This behavior extends to any non continuous function like tan() for example, which is implemented in my project - not without difficulties!)<p>Well the obvious solution is to define your arithmetic over disjoint unions of intervals. This is the subject of a 2017 paper called "Interval Unions" by by Schichl, H., Domes, F., Montanher, T. and Kofler, K..<p>This open-source project I made implements interval union arithmetic in TypeScript in the form of a simple interactive calculator, so you can try it out for yourself! The underlying TypeScript library is dependency free and implements interval union arithmetic over IEEE 754 double precision floats (JS native number type) with outward rounding. This guarantees accuracy of interval results in the presence of rounding issue inherent to floating point.
Show HN: I made a calculator that works over disjoint sets of intervals
I've been studying interval arithmetic for the past few weeks and it's a really interesting field because while there is a ton of super interesting research published over the past decades, it has never really gotten the recognition that it deserves, IMO.<p>One reason for this is that standard interval arithmetic has really poor handling of division by intervals containing zero. If you compute 1 / [-1, 2] in regular interval arithmetic, you get either [-∞, +∞], or you have to say that the operation is undefined. Both solutions are virtually useless. The real answer of course is [-∞, -1] U [0.5, +∞]: i.e. a union of two disjoint intervals.<p>This is useful because you can confidently exclude a non empty set of the real numbers ([-1, 0.5]) from the set of possible values that you can get by dividing 1 by a number between -1 and 2.<p>But this definition of interval division yields a value that is not an interval. This is a problem if you want to define a closed arithmetic system, where you can build and evaluate arbitrary expression over interval values.<p>(This behavior extends to any non continuous function like tan() for example, which is implemented in my project - not without difficulties!)<p>Well the obvious solution is to define your arithmetic over disjoint unions of intervals. This is the subject of a 2017 paper called "Interval Unions" by by Schichl, H., Domes, F., Montanher, T. and Kofler, K..<p>This open-source project I made implements interval union arithmetic in TypeScript in the form of a simple interactive calculator, so you can try it out for yourself! The underlying TypeScript library is dependency free and implements interval union arithmetic over IEEE 754 double precision floats (JS native number type) with outward rounding. This guarantees accuracy of interval results in the presence of rounding issue inherent to floating point.
Show HN: Home Memory – A local DB of my house, down to cables and pipes
Show HN: SPICE simulation → oscilloscope → verification with Claude Code
I built MCP servers for my oscilloscope and SPICE simulator so Claude Code can close the loop between simulation and real hardware.
Show HN: SPICE simulation → oscilloscope → verification with Claude Code
I built MCP servers for my oscilloscope and SPICE simulator so Claude Code can close the loop between simulation and real hardware.
Show HN: PanicLock – Close your MacBook lid disable TouchID –> password unlock
I wrote this after the case of a Washington Post reporter, Hannah Natanson, was compelled to unlock her computer with her fingerprint. This resulted in access to her Desktop Signal on her computer, revealing sources and their conversations.<p><a href="https://www.yahoo.com/news/articles/washington-post-raid-proves-face-153402560.html" rel="nofollow">https://www.yahoo.com/news/articles/washington-post-raid-pro...</a><p>Edit: I've a lot more details about the legality and precedence on the apps landing page <a href="https://paniclock.github.io/" rel="nofollow">https://paniclock.github.io/</a>
Show HN: PanicLock – Close your MacBook lid disable TouchID –> password unlock
I wrote this after the case of a Washington Post reporter, Hannah Natanson, was compelled to unlock her computer with her fingerprint. This resulted in access to her Desktop Signal on her computer, revealing sources and their conversations.<p><a href="https://www.yahoo.com/news/articles/washington-post-raid-proves-face-153402560.html" rel="nofollow">https://www.yahoo.com/news/articles/washington-post-raid-pro...</a><p>Edit: I've a lot more details about the legality and precedence on the apps landing page <a href="https://paniclock.github.io/" rel="nofollow">https://paniclock.github.io/</a>
Show HN: PanicLock – Close your MacBook lid disable TouchID –> password unlock
I wrote this after the case of a Washington Post reporter, Hannah Natanson, was compelled to unlock her computer with her fingerprint. This resulted in access to her Desktop Signal on her computer, revealing sources and their conversations.<p><a href="https://www.yahoo.com/news/articles/washington-post-raid-proves-face-153402560.html" rel="nofollow">https://www.yahoo.com/news/articles/washington-post-raid-pro...</a><p>Edit: I've a lot more details about the legality and precedence on the apps landing page <a href="https://paniclock.github.io/" rel="nofollow">https://paniclock.github.io/</a>
Show HN: Stage – Putting humans back in control of code review
Hey HN! We're Charles and Dean, and we're building Stage: a code review tool that guides you through reading a PR step by step, instead of piecing together a giant diff.<p>Here's a demo video: <a href="https://www.tella.tv/video/stage-demo-1pph" rel="nofollow">https://www.tella.tv/video/stage-demo-1pph</a>.
You can play around with some example PRs here: <a href="https://stagereview.app/explore">https://stagereview.app/explore</a>.<p>Teams are moving faster than ever with AI these days, but more and more engineers are merging changes that they don't really understand. The bottleneck isn't writing code anymore, it's reviewing it.<p>We're two engineers who got frustrated with GitHub's UI for code review. As coding agents took off, we saw our PR backlog pile up faster than we could handle. Not only that, the PRs themselves were getting larger and harder to understand, and we found ourselves spending most of our time trying to build a mental model of what a PR was actually doing.<p>We built Stage to make reviewing a PR feel more like reading chapters of a book, not an unorganized set of paragraphs. We use it every day now, not just to review each other's code but also our own, and at this point we can't really imagine going back to the old GitHub UI.<p>What Stage does: when a PR is opened, Stage groups the changes into small, logical "chapters". These chapters get ordered in the way that makes most sense to read. For each chapter, Stage tells you what changed and specific things to double check. Once you review all the chapters, you're done reviewing the PR.<p>You can sign in to Stage with your GitHub account and everything is synced seamlessly (commenting, approving etc.) so it fits into the workflows you're already used to.<p>What we're not building: a code review bot like CodeRabbit or Greptile. These tools are great for catching bugs (and we use them ourselves!) but at the end of the day humans are responsible for what gets shipped. It's clear that reviewing code hasn't scaled the same way that writing did, and they (we!) need better tooling to keep up with the onslaught of AI generated code, which is only going to grow.<p>We've had a lot of fun building this and are excited to take it further. If you're like us and are also tired of using GitHub for reviewing PRs, we'd love for you to try it out and tell us what you think!
Show HN: Stage – Putting humans back in control of code review
Hey HN! We're Charles and Dean, and we're building Stage: a code review tool that guides you through reading a PR step by step, instead of piecing together a giant diff.<p>Here's a demo video: <a href="https://www.tella.tv/video/stage-demo-1pph" rel="nofollow">https://www.tella.tv/video/stage-demo-1pph</a>.
You can play around with some example PRs here: <a href="https://stagereview.app/explore">https://stagereview.app/explore</a>.<p>Teams are moving faster than ever with AI these days, but more and more engineers are merging changes that they don't really understand. The bottleneck isn't writing code anymore, it's reviewing it.<p>We're two engineers who got frustrated with GitHub's UI for code review. As coding agents took off, we saw our PR backlog pile up faster than we could handle. Not only that, the PRs themselves were getting larger and harder to understand, and we found ourselves spending most of our time trying to build a mental model of what a PR was actually doing.<p>We built Stage to make reviewing a PR feel more like reading chapters of a book, not an unorganized set of paragraphs. We use it every day now, not just to review each other's code but also our own, and at this point we can't really imagine going back to the old GitHub UI.<p>What Stage does: when a PR is opened, Stage groups the changes into small, logical "chapters". These chapters get ordered in the way that makes most sense to read. For each chapter, Stage tells you what changed and specific things to double check. Once you review all the chapters, you're done reviewing the PR.<p>You can sign in to Stage with your GitHub account and everything is synced seamlessly (commenting, approving etc.) so it fits into the workflows you're already used to.<p>What we're not building: a code review bot like CodeRabbit or Greptile. These tools are great for catching bugs (and we use them ourselves!) but at the end of the day humans are responsible for what gets shipped. It's clear that reviewing code hasn't scaled the same way that writing did, and they (we!) need better tooling to keep up with the onslaught of AI generated code, which is only going to grow.<p>We've had a lot of fun building this and are excited to take it further. If you're like us and are also tired of using GitHub for reviewing PRs, we'd love for you to try it out and tell us what you think!
Show HN: Stage – Putting humans back in control of code review
Hey HN! We're Charles and Dean, and we're building Stage: a code review tool that guides you through reading a PR step by step, instead of piecing together a giant diff.<p>Here's a demo video: <a href="https://www.tella.tv/video/stage-demo-1pph" rel="nofollow">https://www.tella.tv/video/stage-demo-1pph</a>.
You can play around with some example PRs here: <a href="https://stagereview.app/explore">https://stagereview.app/explore</a>.<p>Teams are moving faster than ever with AI these days, but more and more engineers are merging changes that they don't really understand. The bottleneck isn't writing code anymore, it's reviewing it.<p>We're two engineers who got frustrated with GitHub's UI for code review. As coding agents took off, we saw our PR backlog pile up faster than we could handle. Not only that, the PRs themselves were getting larger and harder to understand, and we found ourselves spending most of our time trying to build a mental model of what a PR was actually doing.<p>We built Stage to make reviewing a PR feel more like reading chapters of a book, not an unorganized set of paragraphs. We use it every day now, not just to review each other's code but also our own, and at this point we can't really imagine going back to the old GitHub UI.<p>What Stage does: when a PR is opened, Stage groups the changes into small, logical "chapters". These chapters get ordered in the way that makes most sense to read. For each chapter, Stage tells you what changed and specific things to double check. Once you review all the chapters, you're done reviewing the PR.<p>You can sign in to Stage with your GitHub account and everything is synced seamlessly (commenting, approving etc.) so it fits into the workflows you're already used to.<p>What we're not building: a code review bot like CodeRabbit or Greptile. These tools are great for catching bugs (and we use them ourselves!) but at the end of the day humans are responsible for what gets shipped. It's clear that reviewing code hasn't scaled the same way that writing did, and they (we!) need better tooling to keep up with the onslaught of AI generated code, which is only going to grow.<p>We've had a lot of fun building this and are excited to take it further. If you're like us and are also tired of using GitHub for reviewing PRs, we'd love for you to try it out and tell us what you think!
Show HN: Smol machines – subsecond coldstart, portable virtual machines
Show HN: Smol machines – subsecond coldstart, portable virtual machines
Show HN: Smol machines – subsecond coldstart, portable virtual machines