Show HN: Astroworld – A universal N-body gravity engine in Python https://ift.tt/qgVhtmJ

Show HN: Astroworld – A universal N-body gravity engine in Python I’ve been working on a modular N-body simulator in Python called Astroworld. It started as a Solar System visualizer, but I recently refactored it into a general-purpose engine that decouples physical laws from planetary data.Technical Highlights:Symplectic Integration: Uses a Velocity Verlet integrator to maintain long-term energy conservation ($\Delta E/E \approx 10^{-8}$ in stable systems).Agnostic Architecture: It can ingest any system via orbital elements (Keplerian) or state vectors. I've used it to validate the stability of ultra-compact systems like TRAPPIST-1 and long-period perturbations like the Planet 9 hypothesis.Validation: Includes 90+ physical tests, including Mercury’s relativistic precession using Schwarzschild metric corrections.The Planet 9 Experiment:I ran a 10k-year simulation to track the differential signal in the argument of perihelion ($\omega$) for TNOs like Sedna. The result ($\approx 0.002^{\circ}$) was a great sanity check for the engine’s precision, as this effect is secular and requires millions of years to fully manifest.The Stack:NumPy for vectorization, Matplotlib for 2D analysis, and Plotly for interactive 3D trajectories.I'm currently working on a real-time 3D rendering layer. I’d love to get feedback on the integrator’s stability for high-eccentricity orbits or suggestions on implementing more complex gravitational potentials. https://ift.tt/dYj9M2N February 20, 2026 at 01:27AM

Show HN: Nonograms – Friends-only puzzle room with replays and leaderboards https://ift.tt/aDMguKi

Show HN: Nonograms – Friends-only puzzle room with replays and leaderboards Invite code: hackernews. No email required for signup. My friend group loves playing nonograms and competing against each other, but we always send each other screenshots of the solved game grid and time after the fact. So from the start, I knew I wanted leaderboards, replays, and shareable links. I also added PWA support so it can be added to the home screen on mobile and an offline play mode. No ads, analytics or nonsense, just nonograms. Some other goodies as well such as YouTube-like scrubber and KDE-based visualization in replays. https://ift.tt/BrTEMUX Tech stack: React + TypeScript on Vite, hosted on Cloudflare Pages with D1 and Workers https://ift.tt/eDv6IPz February 18, 2026 at 11:23PM

Show HN: I curated 130 US PDF forms and made them fillable in browser https://ift.tt/btBDCNH

Show HN: I curated 130 US PDF forms and made them fillable in browser Hi HN! I built SimplePDF 7 years ago, with the vision from day one to help get rid of bureaucracy (I'm from France, I know what I'm talking about) Fast forward to this week where I finally released something I had on my mind for a long time: a repository of the main US forms that are ready to be filled, straight from the browser, as opposed to having to find a PDF tool online (or local). I focused on healthcare, ED, HR, Legal and IRS/Tax for now. On the tech-side, it's SimplePDF all the way down: client-side processing (the data / documents stay in your browser). I hope you find the resource useful! NiP https://ift.tt/OIQgl8y February 18, 2026 at 12:03AM

Show HN: Self-Hosted Task Scheduling System (Back End and UI and Python SDK) https://ift.tt/7Y5wKvQ

Show HN: Self-Hosted Task Scheduling System (Back End and UI and Python SDK) Hey HN, I’ve been working on a small side project called Cratos and wanted to share it to get feedback. Cratos is a self-hosted task scheduling system. You configure a URL, define when it should be called, and Cratos handles scheduling, retries, execution history, and real-time updates. The goal was to have something lightweight and fully owned - no SaaS dependency, no external cron service. It’s split into three repositories: Backend service: https://ift.tt/xXB4p3N Web dashboard: https://ift.tt/Kkw9OnT Python SDK: https://ift.tt/7ZBmz3T Why I built it: In a few projects, I repeatedly needed reliable scheduled webhooks with: Retry logic Execution logs/history A dashboard to inspect runs Easy local deployment I didn’t want to depend on external services or re-implement job scheduling from scratch every time. The goal was simple deployment (docker compose up) and full control. It’s still early, but usable. I’d especially appreciate feedback from people who’ve built or operated schedulers, cron replacements, or internal job runners I would love some feedback, or tell me how it would be useful to you https://ift.tt/Kkw9OnT February 17, 2026 at 10:39PM

Show HN: Claude-engram – Brain-inspired persistent memory, runs inside Claude.ai https://ift.tt/iLD1c9H

Show HN: Claude-engram – Brain-inspired persistent memory, runs inside Claude.ai Claude.ai artifacts can call the Anthropic API and have persistent storage (5MB via window.storage). I used these two capabilities to build a memory system modeled on how human memory actually works — salience scoring, forgetting curves, and sleep consolidation — all running inside a single React artifact with no external dependencies. Just add artifact to your chat and paste instructions into your personal preferences setting. https://ift.tt/cDrm4aC February 16, 2026 at 10:45PM

Show HN: Please hack my C webserver (it's a collaborative whiteboard) https://ift.tt/t5Y4lqe

Show HN: Please hack my C webserver (it's a collaborative whiteboard) Source code: https://ift.tt/MBW38YK https://ced.quest/draw/ February 16, 2026 at 12:27AM

Show HN: An open-source extension to chat with your bookmarks using local LLMs https://ift.tt/RZiOU2T

Show HN: An open-source extension to chat with your bookmarks using local LLMs I read a lot online and constantly bookmark articles, docs, and resources… then forget why I saved them. Also was very bored on Valentines, so I built a browser extension that lets you chat with your bookmarks directly, using local-first AI (WebLLM running entirely in the browser). The extension downloads and indexes your bookmarked pages, stores them locally, and lets you ask questions. No server, no cloud processing, everything stays on your machine. Very early but it works and planning to add a bunch of stuff. Did I mentioned is open-source, MIT licensed? https://ift.tt/r1XRosO February 15, 2026 at 10:31PM