Show HN Daily Selection (2025-08-21)
- I was curious about spherical helix, ended up making this visualization
- PlutoPrint – Generate PDFs and PNGs from HTML with Python
- Luminal – Open-source, search-based GPU compiler
- Anchor Relay – A faster, easier way to get Let's Encrypt certificates
- Nestable.dev – local whiteboard app with nestable canvases, deep links
- What country you would hit if you went straight where you're pointing
- Bizcardz.ai – Custom metal business cards
- Project management system for Claude Code
- DeVibe – Connecting vibe coders with developers
- 1999date – Dating Like It's 1999
- Okapi – a metrics engine based on open data formats
- We beat Google DeepMind but got killed by Zhipu AI
- Uprintf a universal stb-style printf implementation for C (no OS)
- Hanaco Weather – A poetic weather SNS from the OS Yamato project
- Randomly switching between LMs at every step boosts SWE-bench score
- A neat news website curated and generated by AI
- Because I Kanban
- I built an automatic tool for valuing stocks
- PineBill – make invoices in the browser (free, no ads, no account)
- Network-filter – domains-based whitelist for Docker containers
- LinkedIn Cringe Filter – Categorise LinkedIn posts before you read them
I was curious about spherical helix, ended up making this visualization [Education]
588 points, 106 comments
Interactive visualization of objects moving along a spherical helix path using parametric equations.
- Demonstrates arranging objects along a spherical helix
- Uses parametric equations for 3D movement
- Provides an educational and visual exploration of the concept
Discussion Link, Original Link
PlutoPrint – Generate PDFs and PNGs from HTML with Python [Developer Tools]
68 points, 14 comments
PlutoPrint is a lightweight Python tool for generating high-quality PDFs and PNGs from HTML or XML.
- Built on PlutoBook’s rendering engine for paged media
- Simple Python API for easy integration
- Supports HTML/XML to PDF/PNG conversion
- Works with Matplotlib for chart rendering
- Ideal for invoices, reports, tickets, and snapshots
Discussion Link, Original Link
Luminal – Open-source, search-based GPU compiler [Developer Tools]
79 points, 38 comments
Luminal is an open-source GPU compiler that automatically generates optimized GPU kernels for AI models using search-based compilation.
- Automatically converts high-level model code (e.g., PyTorch-like) into fast GPU kernels
- Uses search-based compilation to explore millions of possible kernels for optimal performance
- Supports ahead-of-time compilation and automatic optimization discovery (e.g., Flash Attention)
- Currently supports Metal (with CUDA in development) and aims to support exotic hardware backends
- Demo available for matrix multiplication optimization on Mac
- Goal: Simplify ML ecosystem while improving performance and hardware utilization
Discussion Link, Original Link
Anchor Relay – A faster, easier way to get Let's Encrypt certificates [Developer Tools]
56 points, 44 comments
Anchor Relay is a free, browser-based tool that simplifies obtaining Let's Encrypt certificates, especially for complex setups like homelabs.
- Streamlines ACME workflow for faster certificate issuance
- Requires only one-time DNS delegation without exposing credentials
- Provides clear insights into the ACME process and renewal reminders
Discussion Link, Original Link
Nestable.dev – local whiteboard app with nestable canvases, deep links [Design]
31 points, 16 comments
Local whiteboard app with nestable canvases and deep linking.
- Supports nested canvases for organized brainstorming
- Enables deep linking for easy sharing and collaboration
- Designed for local use with a focus on simplicity
Discussion Link, Original Link
What country you would hit if you went straight where you're pointing [Entertainment]
60 points, 34 comments
An app that shows which country you'd hit if you traveled straight in the direction your phone is pointing, with historical maps and AI-generated blurbs.
- Uses great-circle calculations to determine the destination country based on phone bearing
- Includes historical maps from different years (1 BC to 1900 AD) for time-travel exploration
- Provides AI-generated descriptions of the pointed-at country/territory
- Works offline with no ads or tracking, using only local data
- Optimized for flat phone orientation for best accuracy
Discussion Link, Original Link
Bizcardz.ai – Custom metal business cards [Business]
18 points, 28 comments
Bizcardz.ai lets users design custom metal business cards that are converted into KiCad PCB schematics for manufacturing.
- Free online design tool
- Converts designs to KiCad PCB schematics
- Manufactured by partners like Elecrow and PCBWay
- Affordable pricing (~$1 per card in bulk)
- Two years in development
Discussion Link, Original Link
Project management system for Claude Code [Developer Tools]
146 points, 99 comments
A lightweight project management system for AI-driven development using GitHub Issues as a database.
- Creates markdown PRDs, epics, and tasks synced with GitHub Issues
- Tracks progress across parallel development streams
- Maintains traceability back to original specs
- CLI-based with fast execution (seconds per command)
- Reduces shipping time by ~50% in internal use
Discussion Link, Original Link
DeVibe – Connecting vibe coders with developers [Business]
3 points, 0 comments
DeVibe connects vibe coders with developers to help turn ideas into production-ready apps.
- Vibe coders can post jobs for developers to apply to
- Developers can list services for immediate booking by vibe coders
- Aims to be the go-to platform for vibe coders needing technical help
- Creates more job opportunities for developers
- Helps ensure safer and more stable apps for end users
Discussion Link, Original Link
1999date – Dating Like It's 1999 [Entertainment]
3 points, 4 comments
A minimalist dating site inspired by 1999 newsletter ads, focusing on simplicity and no algorithms.
- No algorithms or swiping
- No signup required
- Browse profiles in your city
- Submit your own profile to be found
- Retro, straightforward approach to dating
Discussion Link, Original Link
Okapi – a metrics engine based on open data formats [Developer Tools]
7 points, 2 comments
Okapi is an in-memory metrics engine leveraging open data formats and integrating with existing data lakes for flexible, vendor-neutral analytics.
- Uses open data formats to avoid vendor lock-in
- Integrates with OLAP tools like Snowflake, Databricks, and DuckDB
- Stores recent data in-memory for fast queries (sub-millisecond response)
- Rolls up metrics to reduce memory pressure
- Exports older data to object storage (Parquet format)
- Supports high write throughput (~280k samples/second)
- Enables disaggregated storage and compute for scalability
Discussion Link, Original Link
We beat Google DeepMind but got killed by Zhipu AI [Developer Tools]
5 points, 0 comments
An open-source AI framework that mimics human phone interactions, outperforming major labs but now competing against a closed-source giant.
- Outperformed Google DeepMind and Microsoft Research on the AndroidWorld benchmark
- Open-sourced to enable community collaboration
- Developing custom mobile RL gyms for further training
- Small team aiming to compete against large, closed-source labs
Discussion Link, Original Link
Uprintf a universal stb-style printf implementation for C (no OS) [Developer Tools]
13 points, 6 comments
A lightweight, portable printf implementation for embedded and kernel development with zero dependencies.
- Single-header, no dependencies, no dynamic allocation
- Full standard printf support (%d, %x, %f, etc.)
- Extensible with custom format handlers
- Configurable (disable floats, set locale, etc.)
- MIT Licensed
Hanaco Weather – A poetic weather SNS from the OS Yamato project [Entertainment]
17 points, 7 comments
Hanaco Weather is a minimalist, emotion-driven social network for sharing weather-related thoughts, built on the ephemeral OS Yamato platform.
- No likes or followers, focusing on gentle presence
- Part of OS Yamato, a poetic operating system embracing digital impermanence
- Features ephemeral diaries, photos, and chats with seasonal effects
- Includes Wind Messages (time-delayed letters) and a 3D globe for fleeting connections
- Designed for minimalism and digital poetry by a solo developer
Discussion Link, Original Link
Randomly switching between LMs at every step boosts SWE-bench score [Developer Tools]
5 points, 1 comments
Randomly switching between GPT-5 and Sonnet 4 at each step improves SWE-bench performance over using either model alone.
- Achieves 67.2% score on SWE-bench, outperforming GPT-5 (65.0%) and Sonnet 4 (64.8%) individually
- Unpredictable model switching enhances performance unexpectedly
- Detailed experiments and findings available in the blog post
Discussion Link, Original Link
A neat news website curated and generated by AI [Research]
3 points, 0 comments
AI-curated news website focused on neutral, informative content without emotional manipulation.
- Uses AI to curate and generate news content
- Aims to provide unbiased, factual information
- Avoids incendiary or emotionally manipulative content
- Designed to keep readers simply informed
Discussion Link, Original Link
Because I Kanban [Productivity]
5 points, 0 comments
A simple Kanban-style Trello clone built for learning purposes with real-time functionality.
- Simple Kanban board interface
- Easy login with direct access to the board
- Uses socket.io for real-time data transfer
- Free to use with open feedback welcome
Discussion Link, Original Link
I built an automatic tool for valuing stocks [Finance]
3 points, 0 comments
Socks2Stocks is an automated tool for valuing stocks using a discounted cash flow (DCF) calculator.
- Automatically estimates fair value by pulling financial data via API
- Projects free cash flow based on 10-year historical growth rates
- Allows users to input custom assumptions
- Simplified design focused on core DCF functionality
Discussion Link, Original Link
PineBill – make invoices in the browser (free, no ads, no account) [Business]
6 points, 1 comments
A free, browser-based invoicing tool with no ads, accounts, or tracking.
- Runs entirely in the browser
- Live preview of invoices
- Export/Download as PDF
- No ads, tracking, or forced signups
- ~3k monthly active users
Discussion Link, Original Link
Network-filter – domains-based whitelist for Docker containers [Developer Tools]
3 points, 0 comments
A Docker network filter that restricts container access to whitelisted domains using iptables rules.
- Uses
network_mode: 'service:x'to enforce domain-based whitelisting - Operates at the network namespace level to prevent bypasses
- No proxy required, directly drops non-whitelisted traffic
Discussion Link, Original Link
LinkedIn Cringe Filter – Categorise LinkedIn posts before you read them [Productivity]
5 points, 1 comments
A Chrome extension that categorizes LinkedIn posts into user-defined labels like "Cringe" or "Information" before reading.
- Pre-reads and tags LinkedIn posts automatically
- Customizable categories (e.g., "Cringe," "Self-Promotion")
- Seeks feedback on UI and categorization accuracy