Show HN: OpenTimes – Free travel times between U.S. Census geographies https://ift.tt/Tk1BSjR

Show HN: OpenTimes – Free travel times between U.S. Census geographies Hi HN! Today I'm launching OpenTimes, a free database of roughly 150 billion pre-computed, point-to-point travel times between United States Census geographies. In addition to letting you visualize travel isochrones on the homepage, OpenTimes also lets you download massive amounts of travel time data for free and with no limits. The primary goal here is to enable research and fill a gap I noticed in the open-source spatial ecosystem. Researchers (social scientists, economists, etc.) use large travel time matrices to quantify things like access to healthcare, but they often end up paying Google or Esri for the necessary data. By pre-calculating times between commonly-used research geographies (i.e. Census) and then making those times easily accessible via SQL, I hope to make large-scale accessibility research cheaper and simpler. Some technical bits that may be of interest to HN folks: - The entire OpenTimes backend is just static Parquet files on R2. There's no RDBMS or running service. The whole thing costs about $10/month to host and is free to serve. - All travel times were calculated by pre-building the inputs (OSM, OSRM networks) and then distributing the compute over hundreds of GitHub Actions jobs. - The query/SQL layer uses a setup I haven't seen before: a single DuckDB database file with views that point to static Parquet files via HTTP. Finally, the driving times are optimistic since they don't (yet) account for traffic. This is something I hope to work on in the near future. Enjoy! https://opentimes.org March 18, 2025 at 02:10AM

Show HN: A static scanner for LLM app code https://ift.tt/tLQuNJo

Show HN: A static scanner for LLM app code https://ift.tt/fBEAJLG March 17, 2025 at 11:19PM

Show HN: Cppmatch – Rust-Like Pattern Matching and Error Handling for C++ https://ift.tt/Ij2qmMV

Show HN: Cppmatch – Rust-Like Pattern Matching and Error Handling for C++ I've created cppmatch, a lightweight, header-only C++ library that brings Rust-inspired pattern matching and error handling to C++. It tries to imitate the functionality of the questionmark (?) operator in C++ by using a macro that uses the gcc extension https://ift.tt/4KglVTR This allows to create exceptionless code with non-intrusive error-as-value that unlike Exceptions, makes it clear which kinds of error a function can generate and forces you to handle (or ignore) them. The ? operator translates to *expect* To handle the errors I introduce *match* which allows to easily visit the contents of the result or any std::variant (you can use it to imitate rust enums) You can view an example of this project used in a "real way" in compiler-explorer: Simplified error types to just be a string: https://ift.tt/p2AcZEC Multiple structs as error types: https://ift.tt/NlGfV9p Feel free to give feedback or contribute to the project! https://ift.tt/8XDB7ox March 16, 2025 at 10:37PM

Show HN: Cross-platform native UI library for all OS https://ift.tt/DbX0dfV

Show HN: Cross-platform native UI library for all OS https://ift.tt/JfzrLxt March 16, 2025 at 11:19PM

Show HN: Nash, I made a standalone note with single HTML file https://ift.tt/gOQkZGn

Show HN: Nash, I made a standalone note with single HTML file Hello HN, I hope it will posted as well. I made a note in single html file. This does not require a separate membership or installation of the software, and if you download and modify an empty file, you can modify and read it at any time, regardless of online or offline. It can be shared through messengers such as Telegram, so it is also suitable to share contents with long articles and images. It is also possible to host and blog because it is static html file content. https://ift.tt/dQjla9n March 14, 2025 at 07:21AM

Show HN: Kill SaaS with Open Source https://ift.tt/qETm5w7

Show HN: Kill SaaS with Open Source KillSaaS is my answer to subscription software in the AI era. I'm building this because I believe small teams can use modern AI tools to create free alternatives to giants like Figma and DocuSign in weeks, not years. We're creating a platform where developers vote on which SaaS to replace, then build it together as open source. wdyt? https://ift.tt/E7L5KoC March 16, 2025 at 02:50AM

Show HN: Basic Memory – Build a knowledge graph from Claude conversations https://ift.tt/aZD1r7v

Show HN: Basic Memory – Build a knowledge graph from Claude conversations Basic Memory is an open-source tool that enables Claude to build and navigate a persistent knowledge graph based on your conversations. It solves the problem of lost context in AI interactions by storing knowledge in standard Markdown files on your computer. I built this because I found myself constantly repeating information to LLMs and wanted a system where my knowledge grew naturally through conversations while maintaining complete control over my data. Demo video: https://ift.tt/Yey7Shb Key features: - Continue conversations exactly where you left off without repetition - All knowledge stays in local Markdown files you can edit anytime - Works with Claude Desktop via the Model Context Protocol - Seamless integration with Obsidian for visualization and editing - Fully open source (AGPL) The system works by creating structure from simple markdown patterns: - Observations with categories: `- [category] fact #tag` - Relations between documents: `- relation_type [[WikiLink]]` or plain `[[Wikilinks]]` - These patterns emerge naturally during conversations When you chat with Claude, you can simply say "Let's continue our conversation about X" and it will build context from your knowledge base, without needing to upload files every time. GitHub: https://ift.tt/u0e5yjL Docs: https://ift.tt/Ikt6KzD Website: https://ift.tt/ldejx9T Requires Claude Desktop or other MCP host and Python 3.12+ I'd love feedback from the HN community, particularly from those interested in knowledge management or AI applications. https://ift.tt/u0e5yjL March 15, 2025 at 11:49PM