🛠️ Hacker News Tools

[Other] Show HN: Memory Graph – Interactive Python execution and memory visualizer Hello everybody,<p>I built Memory Graph to help students (and myself) build a correct mental model of Python references, mutability, and copying, and to make debugging data structures less “print-driven”. It’s inspired by Python Tutor, but focuses on clearer graphs and on running locally in many different environments and debuggers. The Memory Graph Web Debugger quickly turns your web browser into a Python debugger where the whole program state is visualized in each step, clearly showing aliasing and the structure of the data, giving insight that is hard to get with just printing.<p>Some interesting examples:<p>- Recursion, decimal to binary conversion: <a href="https:&#x2F;&#x2F;memory-graph.com&#x2F;#codeurl=https:&#x2F;&#x2F;raw.githubusercontent.com&#x2F;bterwijn&#x2F;memory_graph&#x2F;refs&#x2F;heads&#x2F;main&#x2F;src&#x2F;binary_convert.py&amp;timestep=1.0&amp;play" rel="nofollow">https:&#x2F;&#x2F;memory-graph.com&#x2F;#codeurl=https:&#x2F;&#x2F;raw.githubusercont...</a><p>- Binary Tree data structure: <a href="https:&#x2F;&#x2F;memory-graph.com&#x2F;#codeurl=https:&#x2F;&#x2F;raw.githubusercontent.com&#x2F;bterwijn&#x2F;memory_graph&#x2F;refs&#x2F;heads&#x2F;main&#x2F;src&#x2F;bin_tree.py&amp;timestep=0.2&amp;play" rel="nofollow">https:&#x2F;&#x2F;memory-graph.com&#x2F;#codeurl=https:&#x2F;&#x2F;raw.githubusercont...</a><p>- Cocktail Shaker Sort: <a href="https:&#x2F;&#x2F;memory-graph.com&#x2F;#codeurl=https:&#x2F;&#x2F;raw.githubusercontent.com&#x2F;bterwijn&#x2F;memory_graph&#x2F;refs&#x2F;heads&#x2F;main&#x2F;src&#x2F;cocktail_sort.py&amp;breakpoints=16,45&amp;continues=1&amp;timestep=0.2&amp;play" rel="nofollow">https:&#x2F;&#x2F;memory-graph.com&#x2F;#codeurl=https:&#x2F;&#x2F;raw.githubusercont...</a><p>Here you can find some difficult Python Data Model exercises for use in education where Memory Graph helps explain the correct answer:<p><pre><code> https:&#x2F;&#x2F;github.com&#x2F;bterwijn&#x2F;memory_graph_videos&#x2F;blob&#x2F;main&#x2F;exercises&#x2F;exercises.md</code></pre>

[Other] Show HN: WOLS – Open standard for mushroom cultivation tracking I built an open labeling standard for tracking mushroom specimens through their lifecycle (from spore&#x2F;culture to harvest).<p>v1.1 adds clonal generation tracking (distinct from filial&#x2F;strain generations) and conforms to JSON-LD for interoperability with agricultural&#x2F;scientific data systems.<p>Spec (CC 4.0): <a href="https:&#x2F;&#x2F;wemush.com&#x2F;open-standard&#x2F;specification" rel="nofollow">https:&#x2F;&#x2F;wemush.com&#x2F;open-standard&#x2F;specification</a> Client libraries (Apache 2.0): Python + CLI: pip install wols (also on GHCR) TypeScript&#x2F;JS: npm install @wemush&#x2F;wols<p>Background: Mycology has fragmented data practices (misidentified species, inconsistent cultivation logs, no shared vocabulary for tracking genetics across generations). This is an attempt to fix that.<p>Looking for feedback from anyone working with biological specimen tracking, agricultural data systems, or mycology.

[Other] Show HN: Open-Source 8-Ch BCI Board (ESP32 and ADS1299 and OpenBCI GUI) Hi HN, I recently shared this on r&#x2F;BCI and wanted to see what the engineering community here thinks.<p>A while back, I got frustrated with the state of accessible BCI hardware. Research gear was wildly unaffordable. So, I spent a ton of time designing a custom board, software and firmware to bridge that gap. I call it the Cerelog ESP-EEG. It is open-source (Firmware + Schematics), and I designed it specifically to fix the signal integrity issues found in most DIY hardware.<p>I believe in sharing the work. You can find the Schematics, Firmware, and Software setup on the GitHub repo: GITHUB LINK: <a href="https:&#x2F;&#x2F;github.com&#x2F;Cerelog-ESP-EEG&#x2F;ESP-EEG" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;Cerelog-ESP-EEG&#x2F;ESP-EEG</a><p>For those who don&#x27;t want to deal with BGA soldering or sourcing components, I do have assembled units available: <a href="https:&#x2F;&#x2F;www.cerelog.com&#x2F;eeg_researchers.html" rel="nofollow">https:&#x2F;&#x2F;www.cerelog.com&#x2F;eeg_researchers.html</a><p>The major features: Forked&#x2F;modified OpenBCI GUI Compatibility as well as Brainflow API, and LSL Compatibility. I know a lot of us rely on the OpenBCI GUI for visualization because it just works. I didn&#x27;t want to reinvent the wheel, so I ensured this board supports it natively.<p>It works out of the box: I maintain a forked modified version of the GUI that connects to the board via LSL (Lab Streaming Layer). Zero coding required: You can visualize FFTs, Spectrograms, and EMG widgets immediately without writing a single line of Python.<p>The &quot;active bias&quot; (why my signal is cleaner): The TI ADS1299 is the gold standard for EEG, but many dev boards implement it incorrectly. They often leave the Bias feedback loop &quot;open&quot; (passive), which makes them terrible at rejecting 60Hz mains hum. I simply followed the datasheet: I implemented a True Closed-Loop Active Bias (Drive Right Leg).<p>How it works: It measures the common-mode signal, inverts it, and actively drives it back into the body. The result: Cleaner data<p>Tech stack:<p><pre><code> ADC: TI ADS1299 (24-bit, 8-channel). MCU: ESP32 Chosen to handle high-speed SPI and WiFi&#x2F;USB streaming Software: BrainFlow support (Python, C++, Java, C#) for those who want to build custom ML pipelines, LSL support, and forked version of OpenBCI GUI support </code></pre> This was a huge project for me. I’m happy to geek out about getting the ESP32 to stream reliably at high sample rates as both the software and firmware for this project proved a lot more challenging than I expected. Let me know what you think!<p>SAFETY NOTE: I strongly recommend running this on a LiPo battery via WiFi. If you must use USB, please use a laptop running on battery power, not plugged into the wall.

[Other] Show HN: OSS sustain guard – Sustainability signals for OSS dependencies Hi HN, I made OSS Sustain Guard.<p>After every high-profile OSS incident, I wonder about the packages I rely on right now. I can skim issues&#x2F;PRs and activity on GitHub, but that doesn’t scale when you have tens or hundreds of dependencies. I built this to surface sustainability signals (maintainer redundancy, activity trends, funding links, etc.) and create awareness. It’s meant to start a respectful conversation, not to judge projects. These are signals, not truth; everything is inferred from public data (internal mirrors&#x2F;private work won’t show up).<p>Quick start: pip install oss-sustain-guard export GITHUB_TOKEN=... os4g check<p>It uses GitHub GraphQL with local caching (no telemetry; token not uploaded&#x2F;stored), and supports multiple ecosystems (Python&#x2F;JS&#x2F;Rust&#x2F;Go&#x2F;Java&#x2F;etc.).<p>Repo: <a href="https:&#x2F;&#x2F;github.com&#x2F;onukura&#x2F;oss-sustain-guard" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;onukura&#x2F;oss-sustain-guard</a><p>I’d love feedback on metric choices&#x2F;thresholds and wording that stays respectful. If you have examples where these signals break down, please share.

[Other] I switched from VSCode to Zed

[Code Quality] Building a Rust-style static analyzer for C++ with AI

[Other] Show HN: An LLM-Powered PCB Schematic Checker (Major Update) Traceformer.io is a web application that ingests KiCad projects or Altium netlists along with relevant datasheets, enabling LLM-based schematic review. The system is designed to identify datasheet-driven schematic issues that traditional ERC tools can&#x27;t detect.<p>Since our first launch (formerly as Netlist.io), we&#x27;ve made some big changes:<p>- Full KiCad project parsing via an open-source plugin<p>- Pass-through API pricing with a small platform fee<p>- Automatic datasheet retrieval<p>- ERC&#x2F;DRC-style review UI<p>- Revamped review workflow with selectable frontier models (GPT 5.2, Opus 4.5, and more)<p>- Configurable review parameters (token limits, design rules, and parallel reviews)<p>Additionally, we continue to offer a free plan which lets you evaluate a design before subscribing. We&#x27;re looking forward to hearing your feedback!

[Other] OpenGitOps

[Other] Show HN: Terminal UI for AWS

[Other] Show HN: I made R/place for LLMs I built AI Place, a vLLM-controlled pixel canvas inspired by r&#x2F;place. Instead of users placing pixels, an LLM paints the grid continuously and you can watch it evolve live.<p>The theme rotates daily. Currently, the canvas is scored using CLIP ViT-B&#x2F;32 against a prompt (e.g., Pixelart of ${theme}). The highest-scoring snapshot is saved to the archive at the end of each day.<p>The agents work in a simple loop:<p>Input: Theme + image of current canvas<p>Output: Python code to update specific pixel coordinates + One word description<p>Tech: Next.js, SSE realtime updates, NVIDIA NIM (Mistral Large 3&#x2F;GPT-OSS&#x2F;Llama 4 Maverick) for the painting decisions<p>Would love feedback! (or ideas for prompts&#x2F;behaviors to try)

[IDE/Editor] Show HN: Hover – IDE style hover documentation on any webpage I thought it would be interesting to have ID style hover docs outside the IDE.<p>Hover is a Chrome extension that gives you IDE style hover tooltips on any webpage: documentation sites, ChatGPT, Claude, etc.<p>How it works: - When a code block comes into view, the extension detects tokens and sends the code to an LLM (via OpenRouter or custom endpoint) - The LLM generates documentation for tokens worth documenting, which gets cached - On hover, the cached documentation is displayed instantly<p>A few things I wanted to get right: - Website permissions are granular and use Chrome&#x27;s permission system, so the extension only runs where you allow it - Custom endpoints let you skip OpenRouter entirely – if you&#x27;re at a company with its own infra, you can point it at AWS Bedrock, Google AI Studio, or whatever you have<p>Built with TypeScript, Vite, and the Chrome extension APIs. Coming to the Chrome Web Store soon.<p>Would love feedback on the onboarding experience and general UX – there were a lot of design decisions I wasn&#x27;t sure about.<p>Happy to answer questions about the implementation.

[Other] Show HN: An interactive guide to how browsers work

[Other] Show HN: Rails-like web framework for Go Over the past couple of months I have been working on my own framework the encapsulates how I have come to build web apps using Go.<p>The aim is to make it faster and easier to build full-stack web applications that fully embraces hypermedia instead of JSON data API backend + SPA fronted<p>It&#x27;s getting close to a v1-beta release but the core structure and functionality is there.<p>Would love to hear hn&#x27;s thoughts!

[Other] Show HN: I built an HTTP/2 server in C++ to learn the protocol and language I wanted to learn more about the HTTP&#x2F;2 protocol but also deep dive into modern C++ development. I&#x27;m currently using it to host my personal web site - <a href="https:&#x2F;&#x2F;www.roberthargreaves.com" rel="nofollow">https:&#x2F;&#x2F;www.roberthargreaves.com</a>.<p>I&#x27;ve also blogged a bit about the development process, hosting options and steps I took to harden the application against attack - <a href="https:&#x2F;&#x2F;blog.roberthargreaves.com&#x2F;2026&#x2F;01&#x2F;03&#x2F;building-hosting-ion-http2-server" rel="nofollow">https:&#x2F;&#x2F;blog.roberthargreaves.com&#x2F;2026&#x2F;01&#x2F;03&#x2F;building-hostin...</a><p>It&#x27;s by no means a complete implementation of HTTP&#x2F;2, but I think I&#x27;ve achieved the main aims I was hoping to achieve with it!<p>I would love some feedback though from more experienced folks if there&#x27;s some egregious failings which I should address.

[Other] 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&#x27;m often unfamiliar with these platforms myself. &quot;Go to App Store Connect and generate a P8 key&quot; okay but where? I end up spending 10 minutes navigating menus I&#x27;ve never seen before.<p>I started delegating these tasks to Perplexity&#x27;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&#x27;s agentic browsing just works better in my experience.<p>Comet doesn&#x27;t have an API, so this uses CDP to communicate with it directly.

[Other] Show HN: Self-hosted email server for 2026 – single binary, CalDAV Built this after getting frustrated with the paying to a google for email. Now running it for 1 months in production.<p>What it does: - Full SMTP server (inbound&#x2F;outbound, DKIM signing, SPF&#x2F;DMARC checking) - IMAP with IDLE support - CalDAV&#x2F;CardDAV (replace Google Calendar&#x2F;Contacts) - Web admin panel with Prometheus metrics - Greylisting for spam prevention - Auto-discovery (mail clients configure themselves) - Audit logging for compliance<p>What it doesn&#x27;t do: - Webmail (use Roundcube, etc.) - ML-based spam filtering (greylisting + basic heuristics only) - Clustering&#x2F;HA

[Other] Show HN: Vibe Coding a static site on a $25 Walmart Phone Hi! I took a cheap $25 walmart phone and put a static server on it? Why? Just for a fun weekend project.<p>I used Claude Code for most of the setup. I had a blast.<p>It&#x27;s running termux, andronix, nginx, cloudflared and even a prometheus node exporter.<p>Here&#x27;s the site:<p><a href="https:&#x2F;&#x2F;walmartphone.stetsonblake.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;walmartphone.stetsonblake.com&#x2F;</a>

[Other] Show HN: Open database of link metadata for large-scale analysis

[DevOps] Show HN: Offline tiles and routing and geocoding in one Docker Compose stack Hi HN,<p>I’m building Corviont, a self-hosted offline maps appliance (tiles + routing + search) for edge&#x2F;on-prem devices.<p>Hosted demo (no install): <a href="https:&#x2F;&#x2F;demo.corviont.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;demo.corviont.com&#x2F;</a><p>Self-host (Docker Compose repo): <a href="https:&#x2F;&#x2F;github.com&#x2F;corviont&#x2F;monaco-demo" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;corviont&#x2F;monaco-demo</a><p>Docs: <a href="https:&#x2F;&#x2F;www.corviont.com&#x2F;docs" rel="nofollow">https:&#x2F;&#x2F;www.corviont.com&#x2F;docs</a><p>What’s inside:<p><pre><code> - Vector tiles served locally (PMTiles) - Routing served locally (Valhalla) - Offline geocoding&#x2F;search + reverse (SQLite Nominatim-based index) - MapLibre UI wired to the local endpoints </code></pre> After the initial image + data pulls, it runs fully offline (no external map&#x2F;routing&#x2F;geocoding API calls).<p>Next (if people need it): a signed on-device updater for regional datasets (verify → atomic swap → reload).<p>I’d love feedback: where offline maps&#x2F;routing&#x2F;search matters for you, and what constraints bite (hardware, fleet size, update windows, regions, deployment style).

[Code Quality] Show HN: FP-pack – Functional pipelines in TypeScript without monads Hi HN,<p>I built fp-pack, a small TypeScript functional utility library focused on pipe-first composition.<p>The goal is to keep pipelines simple and readable, while still supporting early exits and side effects — without introducing monads like Option or Either.<p>Most code uses plain pipe&#x2F;pipeAsync. For the few cases that need early termination, fp-pack provides a SideEffect-based pipeline that short-circuits safely.<p>I also wrote an “AI agent skills” document to help LLMs generate consistent fp-pack-style code.<p>Feedback, criticism, or questions are very welcome.