The best Hacker News stories from Show from the past day

from

All Show

from the past*

day week month

with these search terms:

Create follow Go back

Latest posts:

Show HN: The Alphabetical Clock

Show HN: Public transit systems as data – lines, stations, railcars, and history

Show HN: Coasts – Containerized Hosts for Agents

Hi HN - We've been working on Coasts (“containerized hosts”) to make it so you can run multiple localhost instances, and multiple docker-compose runtimes, across git worktrees on the same computer. Here’s a demo: <a href="https://www.youtube.com/watch?v=yRiySdGQZZA" rel="nofollow">https://www.youtube.com/watch?v=yRiySdGQZZA</a>. There are also videos in our docs that give a good conceptual overview: <a href="https://coasts.dev/docs/learn-coasts-videos">https://coasts.dev/docs/learn-coasts-videos</a>.<p>Agents can make code changes in different worktrees in isolation, but it's hard for them to test their changes without multiple localhost runtimes that are isolated and scoped to those worktrees as well. You can do it up to a point with port hacking tricks, but it becomes impractical when you have a complex docker-compose with many services and multiple volumes.<p>We started playing with Codex and Conductor in the beginning of this year and had to come up with a bunch of hacky workarounds to give the agents access to isolated runtimes. After bastardizing our own docker-compose setup, we came up with Coasts as a way for agents to have their own runtimes without having to change your original docker-compose.<p>A containerized host (from now on we’ll just say “coast” for short) is a representation of your project's runtime, like a devcontainer but without the IDE stuff—it’s just focused on the runtime. You create a Coastfile at your project root and usually point to your project's docker-compose from there. When you run `coast build` next to the Coastfile you will get a build (essentially a docker image) that can be used to spin up multiple Docker-in-Docker runtimes of your project.<p>Once you have a coast running, you can then do things like assign it to a worktree, with `coast assign dev-1 -w worktree-1`. The coast will then point at the worktree-1 root.<p>Under the hood the host project root and any external worktree directories are Docker-bind-mounted into the container at creation time but the /workspace dir, where we run the services of the coast from, is a separate Linux bind mount that we create inside the running container. When switching worktrees we basically just do umount -l /workspace, mount --bind <path_to_worktree_root>, mount --make-rshared /workspace inside of the running coast. The rshared flag sets up mount propagation so that when we remount /workspace, the change flows down to the inner Docker daemon's containers.<p>The main idea is that the agents can continue to work host-side but then run exec commands against a specific coast instance if they need to test runtime changes or access runtime logs. This makes it so that we are harness agnostic and create interoperability around any agent or agent harness that runs host-side.<p>Each coast comes with its own set of dynamic ports: you define the ports you wish to expose back to the host machine in the Coastfile. You're also able to "checkout" a coast. When you do that, socat binds the canonical ports of your coast (e.g. web 3000, db 5432) to the host machine. This is useful if you have hard coded ports in your project or need to do something like test webhooks.<p>In your Coastfile you point to all the locations on your host-machine where you store your worktrees for your project (e.g. ~/.codex/worktrees). When an agent runs `coast lookup` from a host-side worktree directory, it is able to find the name of the coast instance it is running on, so it can do things like call `coast exec dev-1 make tests`. If your agent needs to do things like test with Playwright it can so that host-side by using the dynamic port of your frontend.<p>You can also configure volume topologies, omit services and volumes that your agent doesn't need, as well as share certain services host-side so you don't add overhead to each coast instance. You can also do things like define strategies for how each service should behave after a worktree assignment change (e.g. none, hot, restart, rebuild). This helps you optimize switching worktrees so you don't have to do a whole docker-compose down and up cycle every time.<p>We'd love to answer any questions and get your feedback!

Show HN: I made a "programming language" looking for feedback

Show HN: Crazierl – An Erlang Operating System

Crazierl is an experimental/hobby operating system based around BEAM.<p>I've linked the browser based demo; I don’t recommend using a phone; it does work, slowly, on the phones I tested, but it’s very awkward to use. You can share a link with a hashtag with your friends and click the consent checkbox, and it (should) link up into dist and I’ve also included a chat application you can start with chat:start(). (quit chat with /quit, or use the shell menu with ctrl-g to switch between shells etc).<p>The browser demo relies on the v86 javascript x86 virtual machine. You can also run Crazierl on a real x86 system, but I’ve had mixed luck on modern systems, it uses some esoteric legacy VGA features and support for that isn’t getting better.<p>Crazierl is fairly limited: 32-bit x86, BIOS boot, only two NIC drivers virtio-net and realtek 8168. But it's got enough to become part of an Erlang dist cluster. It also supports SMP, but it’s crashy with high core counts in qemu; there’s almost certainly several concurrency bugs in the kernel. There's also a lot of excess tcp debug spew (sorry).<p>Source code is available (Apache) <a href="https://github.com/russor/crazierl/" rel="nofollow">https://github.com/russor/crazierl/</a>

Show HN: 30u30.fyi – Is your startup founder on Forbes' most fraudulent list?

Show HN: I built an OS that is pure AI

I've been building Pneuma, a desktop computing environment where software doesn't need to exist before you need it. There are no pre-installed applications. You boot to a blank screen with a prompt. You describe what you want: a CPU monitor, a game, a notes app, a data visualizer and a working program materializes in seconds. Once generated, agents persist. You can reuse them, they can communicate with each other through IPC, and you can share them through a community agent store. The idea isn't that everything is disposable. It's that creation is instant and the barrier to having exactly the tool you need is just describing it.<p>Under the hood: your input goes to an LLM, which generates a self-contained Rust module. That gets compiled to WebAssembly in under a second, then JIT-compiled and executed in a sandboxed Wasmtime instance. Everything is GPU-rendered via wgpu (Vulkan/Metal/DX12). If compilation fails, the error is automatically fed back for correction. ~90% first-attempt success rate.<p>The architecture is a microkernel: agents run in isolated WASM sandboxes with a typed ABI for drawing, input, storage, and networking. An agent crash can't bring down the system. Agents can run side by side, persist to a local store, and be shared or downloaded from the community store.<p>Currently it runs as a desktop app on Linux, macOS, and Windows. The longer-term goal is to run on bare metal and support existing ARM64 binaries alongside generated agents. A full computing environment where AI-generated software and traditional applications coexist.<p>Built entirely in Rust.<p>I built this because I think the traditional software model of find an app, install it, learn it, configure it; is unnecessary friction. If a computer can generate exactly the tool you need in the moment you need it, and then keep it around when it's useful, why maintain a library of pre-built software at all?<p>Free tier available (no credit card). There's a video on the landing page showing it in action.<p>Interested in feedback on the concept, the UX, and whether this is something you'd actually use.

Show HN: PeriodicTableOfElements.org

Show HN: QuickBEAM – run JavaScript as supervised Erlang/OTP processes

QuickBEAM is a JavaScript runtime embedded inside the Erlang/OTP VM.<p>If you’re building a full-stack app, JavaScript tends to leak in anyway — frontend, SSR, or third-party code.<p>QuickBEAM runs that JavaScript inside OTP supervision trees.<p>Each runtime is a process with a `Beam` global that can: - call Elixir code - send/receive messages - spawn and monitor processes - inspect runtime/system state<p>It also provides browser-style APIs backed by OTP/native primitives (fetch, WebSocket, Worker, BroadcastChannel, localStorage, native DOM, etc.).<p>This makes it usable for: - SSR - sandboxed user code - per-connection state - backend JS with direct OTP interop<p>Notable bits:<p>- JS runtimes are supervised and restartable - sandboxing with memory/reduction limits and API control - native DOM that Erlang can read directly (no string rendering step) - no JSON boundary between JS and Erlang - built-in TypeScript, npm support, and native addons<p>QuickBEAM is part of Elixir Volt — a full-stack frontend toolchain built on Erlang/OTP with no Node.js.<p>Still early, feedback welcome.

Show HN: QuickBEAM – run JavaScript as supervised Erlang/OTP processes

QuickBEAM is a JavaScript runtime embedded inside the Erlang/OTP VM.<p>If you’re building a full-stack app, JavaScript tends to leak in anyway — frontend, SSR, or third-party code.<p>QuickBEAM runs that JavaScript inside OTP supervision trees.<p>Each runtime is a process with a `Beam` global that can: - call Elixir code - send/receive messages - spawn and monitor processes - inspect runtime/system state<p>It also provides browser-style APIs backed by OTP/native primitives (fetch, WebSocket, Worker, BroadcastChannel, localStorage, native DOM, etc.).<p>This makes it usable for: - SSR - sandboxed user code - per-connection state - backend JS with direct OTP interop<p>Notable bits:<p>- JS runtimes are supervised and restartable - sandboxing with memory/reduction limits and API control - native DOM that Erlang can read directly (no string rendering step) - no JSON boundary between JS and Erlang - built-in TypeScript, npm support, and native addons<p>QuickBEAM is part of Elixir Volt — a full-stack frontend toolchain built on Erlang/OTP with no Node.js.<p>Still early, feedback welcome.

Show HN: Create a full language server in Go with 3.17 spec support

Show HN: Create a full language server in Go with 3.17 spec support

Show HN: BreezePDF – Free, in-browser PDF editor

BreezePDF lets you edit, sign, merge, compress, redact, OCR, fill forms, extract tables, and use 30+ more PDF tools — all in the browser, no sign-up. Files never leave your computer.<p>I built it because when people search Google for common PDF tasks, many of the tools they find upload documents to a server. I wanted an option that keeps files local instead.<p>I posted an earlier version on HN last spring: <a href="https://news.ycombinator.com/item?id=43880962">https://news.ycombinator.com/item?id=43880962</a><p>At the time it only supported a small set of features. Over the last 10 months I rebuilt large parts of it and expanded it to nearly 40 tools, including several ideas that came from comments in that earlier thread.<p>There is also now a desktop app for macOS, Windows, and Linux, plus a CLI/SDK for developers.

Show HN: BreezePDF – Free, in-browser PDF editor

BreezePDF lets you edit, sign, merge, compress, redact, OCR, fill forms, extract tables, and use 30+ more PDF tools — all in the browser, no sign-up. Files never leave your computer.<p>I built it because when people search Google for common PDF tasks, many of the tools they find upload documents to a server. I wanted an option that keeps files local instead.<p>I posted an earlier version on HN last spring: <a href="https://news.ycombinator.com/item?id=43880962">https://news.ycombinator.com/item?id=43880962</a><p>At the time it only supported a small set of features. Over the last 10 months I rebuilt large parts of it and expanded it to nearly 40 tools, including several ideas that came from comments in that earlier thread.<p>There is also now a desktop app for macOS, Windows, and Linux, plus a CLI/SDK for developers.

Show HN: Sheet Ninja – Google Sheets as a CRUD Back End for Vibe Coders

Show HN: Sheet Ninja – Google Sheets as a CRUD Back End for Vibe Coders

Show HN: We built a multi-agent research hub. The waitlist is a reverse-CAPTCHA

Hey HN,<p>Automated research is the next big step in AI, with companies like OpenAI aiming to debut a fully automated researcher by 2028 (<a href="https://www.technologyreview.com/2026/03/20/1134438/openai-is-throwing-everything-into-building-a-fully-automated-researcher/" rel="nofollow">https://www.technologyreview.com/2026/03/20/1134438/openai-i...</a>). However, there is a very real possibility that much of this corporate research will remain closed to the general public.<p>To counter this, we spent the last month building Enlidea---a machine-to-machine ecosystem for open research.<p>It's a decentralized research hub where autonomous agents propose hypotheses, stake bounties, execute code, and perform automated peer reviews on each other's work to build consensus.<p>The MVP is almost done, but before launching, we wanted to filter the waitlist for developers who actually know how to orchestrate agents.<p>Because of this, there is no real UI on the landing page. It's an API handshake. Point your LLM agent at the site and see if it can figure out the payload to whitelist your email.

Show HN: Foundry: a Markdown-first CMS written in Go

Hi HN! I've been building a CMS called Foundry, brought together from multiple smaller private projects as well as greenfield code.<p>The short version is: it's a CMS written in Go with a focus on markdown content, a simple hook-based plugin model, themes, archetypes, preview flows, and a clean authoring/developer experience.<p>I started working on it because I wanted something that was more powerful than Hugo for a few of my websites, without having to resort to dangling onto a database.<p>What seems different about it, at least to me, is that I'm trying to keep the system small in concept: local content, explicit behavior, compile-time plugin registration, and an admin/editor layer that is meant to stay close to how the content actually lives on disk. The goal is not to make "yet another website builder", but to make a CMS that is easy to use and quick to onramp onto, but has powerful advanced features and extensibility.<p>Still early, but usable enough that I wanted to put it in front of people here and get feedback. Please don't castigate me on the UI look - I'm not a designer, and the themes are basically clones of each other.<p>Happy to answer technical questions, architecture questions, or hear where this seems useful versus where it does not.

Show HN: Sup AI, a confidence-weighted ensemble (52.15% on Humanity's Last Exam)

Hi HN. I'm Ken, a 20-year-old Stanford CS student. I built Sup AI.<p>I started working on this because no single AI model is right all the time, but their errors don’t strongly correlate. In other words, models often make unique mistakes relative to other models. So I run multiple models in parallel and synthesize the outputs by weighting segments based on confidence. Low entropy in the output token probability distributions correlates with accuracy. High entropy is often where hallucinations begin.<p>My dad Scott (AI Research Scientist at TRI) is my research partner on this. He sends me papers at all hours, we argue about whether they actually apply and what modifications make sense, and then I build and test things. The entropy-weighting approach came out of one of those conversations.<p>In our eval on Humanity's Last Exam, Sup scored 52.15%. The best individual model in the same evaluation run got 44.74%. The relative gap is statistically significant (p < 0.001).<p>Methodology, eval code, data, and raw results:<p>- <a href="https://sup.ai/research/hle-white-paper-jan-9-2026" rel="nofollow">https://sup.ai/research/hle-white-paper-jan-9-2026</a><p>- <a href="https://github.com/supaihq/hle" rel="nofollow">https://github.com/supaihq/hle</a><p>Limitations:<p>- We evaluated 1,369 of the 2,500 HLE questions (details in the above links)<p>- Not all APIs expose token logprobs; we use several methods to estimate confidence when they don't<p>We tried offering free access and it got abused so badly it nearly killed us. Right now the sustainable option is a $5 starter credit with card verification (no auto-charge). If you don't want to sign up, drop a prompt in the comments and I'll run it myself and post the result.<p>Try it at <a href="https://sup.ai" rel="nofollow">https://sup.ai</a>. My dad Scott (@scottmu) is in the thread too. Would love blunt feedback, especially where this really works for you and where it falls short.<p>Here's a short demo video: <a href="https://www.youtube.com/watch?v=DRcns0rRhsg" rel="nofollow">https://www.youtube.com/watch?v=DRcns0rRhsg</a>

Show HN: Free, in-browser PDF editor

Edit, sign, merge, compress, redact, OCR, fill forms, extract tables, and 30+ more tools — all in the browser, no sign-up. Files never leave your computer. Now with a desktop app (macOS/Windows/Linux) and a CLI/SDK for developers.<p>Last time this was posted it was in it's infancy, and how I've added a bunch more to it