The best Hacker News stories from Show from the past week
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Show HN: Bolt – A super-fast, statically-typed scripting language written in C
I've built many interpreters over the years, and Bolt represents my attempt at building the scripting language I always wanted. This is the first public release, 0.1.0!<p>I've felt like most embedded languages have been moving towards safety and typing over years, with things like Python type hints, the explosive popularity of typescript, and even typing in Luau, which powers one of the largest scripted evironments in the world.<p>Bolt attempts to harness this directly in the lagnauge rather than as a preprocessing step, and reap benefits in terms of both safety and performance.<p>I intend to be publishing toys and examples of applications embedding Bolt over the coming few weeks, but be sure to check out the examples and the programming guide in the repo if you're interested!
Show HN: Engineering.fyi – Search across tech engineering blogs in one place
I built a search engine for engineering blogs because I was tired of manually checking individual company blogs to find real-world production examples.<p>The problem: When learning a new technology, the best insights often come from how companies like Google, Meta, or Stripe actually implement it in production. But these gems are scattered across dozens of separate engineering blogs with no way to search across them.<p>What I built: Engineering.fyi indexes engineering blogs from ~15 companies (Google, Meta, OpenAI, Anthropic, Stripe, Uber, etc.) and makes them searchable in one place. You can filter by topic, difficulty level, and whether articles include code samples.<p>Technical details:
- Built with Next.js, SQLite, DrizzleORM
- Custom scrapers for each blog (they're all frustratingly different)
- Basic tagging system using content matching (still improving this)<p>Current status: Core search is working. Adding new blogs weekly as I index them.<p>Next features (based on early feedback):
- AI summaries for quick article previews
- Weekly digest of trending engineering insights
- Save/bookmark articles (considering whether to add accounts)<p>Interesting challenges:
- Each blog requires custom parsing logic (no standard format)
- Building an accurate tagging system is harder than expected – started with exact matching but exploring better approaches<p>I'd love feedback on:
- Which company engineering blogs you'd find most valuable to include
- Whether AI summaries would actually be useful or just noise
- How you currently discover engineering articles from these companies
Show HN: The current sky at your approximate location, as a CSS gradient
For HTML Day 2025 [1], I made a web service that displays the current sky at your approximate location as a CSS gradient. Colours are simulated on-demand using atmospheric absorption and scattering coefficients. Updates every minute, without the use of client-side JavaScript.<p>Source code and additional information is available on GitHub: <a href="https://github.com/dnlzro/horizon" rel="nofollow">https://github.com/dnlzro/horizon</a><p>[1] <a href="https://html.energy/html-day/2025/index.html" rel="nofollow">https://html.energy/html-day/2025/index.html</a>
Show HN: An open-source e-book reader for conversational reading with an LLM
Hi HN! I've been working on BookWith, an open-source e-book reader that integrates AI as your reading companion.<p>The problem: Traditional e-readers are passive. When you encounter something unclear, you have to context-switch to search for it. Your highlights and notes remain isolated, and you can't easily connect ideas across different books.<p>My solution: BookWith embeds an AI that maintains full context of what you're reading. It features:<p>- Context-aware AI chat: Ask questions about the current page/chapter and get instant answers<p>- AI podcast generation: Automatically converts book content into conversational podcasts using Google Cloud TTS<p>- Multi-layer memory system: Short-term (last 5 conversations), mid-term (summarized every 20), and long-term (vector search) memory that maintains continuity across reading sessions<p>- Smart annotations: 5-color highlighting system that AI can reference and analyze<p>Technical stack: Built as a fork of Flow (epub reader), with added LLM integration and vector database for semantic search. Supports multiple LLMs and languages (EN/JA/ZH).
Show HN: Kitten TTS – 25MB CPU-Only, Open-Source TTS Model
Kitten TTS is an open-source series of tiny and expressive text-to-speech models for on-device applications. We are excited to launch a preview of our smallest model, which is less than 25 MB. This model has 15M parameters.<p>This release supports English text-to-speech applications in eight voices: four male and four female. The model is quantized to int8 + fp16, and it uses onnx for runtime. The model is designed to run literally anywhere eg. raspberry pi, low-end smartphones, wearables, browsers etc. No GPU required!<p>We're releasing this to give early users a sense of the latency and voices that will be available in our next release (hopefully next week). We'd love your feedback! Just FYI, this model is an early checkpoint trained on less than 10% of our total data.<p>We started working on this because existing expressive OSS models require big GPUs to run them on-device and the cloud alternatives are too expensive for high frequency use. We think there's a need for frontier open-source models that are tiny enough to run on edge devices!
Show HN: Whittle – A shrinking word game
Whittle is a small word game I've been working on. Each phrase must be whittled down by one letter (or space) each turn. The remaining phrase must still consist of valid words. That's it! There's a daily puzzle, as well as an archive of old puzzles.<p>The idea for the game came to me in a dream (really) and I built the puzzle generator with my partner, who's also a software engineer. It's a labor of love! Any feedback or suggestions are welcome. Thanks for playing!
Show HN: I've been building an ERP for manufacturing for the last 3 years
Show HN: I spent 6 years building a ridiculous wooden pixel display
I built the world's most impractical 1000-pixel display and anyone in the world can draw on it. It draws a single pixel at a time and takes 30-60 minutes to complete a single image. Anyone can participate in the project by voting for the next image to be drawn, and submitting images.<p><a href="https://kilopx.com/" rel="nofollow">https://kilopx.com/</a>
Show HN: WebGPU enables local LLM in the browser – demo site with AI chat
Browser LLM demo working on JavaScript and WebGPU.
WebGPU is already supported in Chrome, Safari, Firefox, iOS (v26) and Android.<p>Demo, similar to ChatGPT <a href="https://andreinwald.github.io/browser-llm/" rel="nofollow">https://andreinwald.github.io/browser-llm/</a><p>Code <a href="https://github.com/andreinwald/browser-llm">https://github.com/andreinwald/browser-llm</a><p>- No need to use your OPENAI_API_KEY - its local model that runs on your device<p>- No network requests to any API<p>- No need to install any program<p>- No need to download files on your device (model is cached in browser)<p>- Site will ask before downloading large files (llm model) to browser cache<p>- Hosted on Github Pages from this repo - secure, because you see what you are running
Show HN: WebGPU enables local LLM in the browser – demo site with AI chat
Browser LLM demo working on JavaScript and WebGPU.
WebGPU is already supported in Chrome, Safari, Firefox, iOS (v26) and Android.<p>Demo, similar to ChatGPT <a href="https://andreinwald.github.io/browser-llm/" rel="nofollow">https://andreinwald.github.io/browser-llm/</a><p>Code <a href="https://github.com/andreinwald/browser-llm">https://github.com/andreinwald/browser-llm</a><p>- No need to use your OPENAI_API_KEY - its local model that runs on your device<p>- No network requests to any API<p>- No need to install any program<p>- No need to download files on your device (model is cached in browser)<p>- Site will ask before downloading large files (llm model) to browser cache<p>- Hosted on Github Pages from this repo - secure, because you see what you are running
Show HN: Draw a fish and watch it swim with the others
Made this website as an exercise in vibe-coding and GCP. It was posted about a few times around the internet, on sites like [Morning Brew](<a href="https://www.morningbrew.com/issues/business-buzzkill" rel="nofollow">https://www.morningbrew.com/issues/business-buzzkill</a>), [MetaFilter](<a href="https://www.metafilter.com/209703/Draw-A-Fish" rel="nofollow">https://www.metafilter.com/209703/Draw-A-Fish</a>), boingboing.net, etc. I think it's cute!<p>I built a basic CNN trained against penises and swastikas, and then anything that doesn't hit the 63% confidence score gets sent to a mod queue, a [vibe-coded fish-tinder](<a href="https://bsky.app/profile/bigass.bsky.social/post/3luvikxn3f22n" rel="nofollow">https://bsky.app/profile/bigass.bsky.social/post/3luvikxn3f2...</a>).<p>Was a fun exercise, spent about a month on it. Frontend is HTML5 hosted on github pages, backend is Node.JS on GCP.
Show HN: Draw a fish and watch it swim with the others
Made this website as an exercise in vibe-coding and GCP. It was posted about a few times around the internet, on sites like [Morning Brew](<a href="https://www.morningbrew.com/issues/business-buzzkill" rel="nofollow">https://www.morningbrew.com/issues/business-buzzkill</a>), [MetaFilter](<a href="https://www.metafilter.com/209703/Draw-A-Fish" rel="nofollow">https://www.metafilter.com/209703/Draw-A-Fish</a>), boingboing.net, etc. I think it's cute!<p>I built a basic CNN trained against penises and swastikas, and then anything that doesn't hit the 63% confidence score gets sent to a mod queue, a [vibe-coded fish-tinder](<a href="https://bsky.app/profile/bigass.bsky.social/post/3luvikxn3f22n" rel="nofollow">https://bsky.app/profile/bigass.bsky.social/post/3luvikxn3f2...</a>).<p>Was a fun exercise, spent about a month on it. Frontend is HTML5 hosted on github pages, backend is Node.JS on GCP.
Show HN: Draw a fish and watch it swim with the others
Made this website as an exercise in vibe-coding and GCP. It was posted about a few times around the internet, on sites like [Morning Brew](<a href="https://www.morningbrew.com/issues/business-buzzkill" rel="nofollow">https://www.morningbrew.com/issues/business-buzzkill</a>), [MetaFilter](<a href="https://www.metafilter.com/209703/Draw-A-Fish" rel="nofollow">https://www.metafilter.com/209703/Draw-A-Fish</a>), boingboing.net, etc. I think it's cute!<p>I built a basic CNN trained against penises and swastikas, and then anything that doesn't hit the 63% confidence score gets sent to a mod queue, a [vibe-coded fish-tinder](<a href="https://bsky.app/profile/bigass.bsky.social/post/3luvikxn3f22n" rel="nofollow">https://bsky.app/profile/bigass.bsky.social/post/3luvikxn3f2...</a>).<p>Was a fun exercise, spent about a month on it. Frontend is HTML5 hosted on github pages, backend is Node.JS on GCP.
Show HN: I made a website that makes you cry
Show HN: I made a website that makes you cry
Show HN: AgentMail – Email infra for AI agents
Hey HN, we're Haakam, Michael, and Adi. We're building AgentMail (<a href="https://agentmail.to/">https://agentmail.to/</a>), an API to give AI agents their own email inboxes. We’re not talking about AI for your email, this is email for your AI.<p>We started building email agents because they can converse with users in their inboxes, automate email-based workflows, and authenticate with third-party applications. Given these unique capabilities, we think email will be a core interface for agents.<p>But we were building on top of Gmail, which was a struggle: poor API support, expensive subscriptions, rate limits, sending limits, GCP Pub/Sub, OAuth, crappy keyword search, and an overall terrible developer experience.<p>Gmail and other providers didn’t work for us. So we decided to bite the bullet and build our own.<p>AgentMail is like Gmail, but API-first, with programmatic inbox creation, events over webhooks and websockets, simple API key auth, organization-wide semantic search, structured data extraction, and usage-based pricing that scales with emails sent/received.<p>Here’s a demo of building an email agent: <a href="https://youtu.be/1V7BISeFUTM" rel="nofollow">https://youtu.be/1V7BISeFUTM</a>, and here’s a demo of a voice agent with its own email inbox: <a href="https://youtu.be/eG2fCsRK4RY" rel="nofollow">https://youtu.be/eG2fCsRK4RY</a><p>So far AgentMail has been deployed to use cases such as apps with dedicated inboxes for each user, voice agents that receive documents in real time, automated account provisioning and QA testing, cold outbound platforms with thousands of inboxes, automations for processing invoices, and agents that coordinate work with humans and other agents.<p>We would love to hear your thoughts and feedback. You can try our playground at <a href="https://chat.agentmail.to">https://chat.agentmail.to</a>
Show HN: Mcp-use – Connect any LLM to any MCP
Hey Pietro and Luigi here, we are the authors of mcp-use (<a href="https://github.com/mcp-use/mcp-use">https://github.com/mcp-use/mcp-use</a>).<p>When the first MCP servers came out we were very excited about the technology, but as soon as we wanted to get our hands dirty, we found out that MCP could be used only through Claude Desktop or Cursor. As engineers, we did not like that. MCP seemed like something you wanted to use to build products and applications yourself, not something to hide behind a closed source application.<p>So we approached the SDK but were pretty dissatisfied with the developer experience (double async loops, lots of boilerplate). We decided to write mcp-use to make our lives easier.<p>mcp-use lets you connect any LLM to any MCP server in just 6 lines of code. We provide a high level abstraction over the official MCP SDK that makes your life easier and supports all the functionalities of the protocol.<p>Demo video here: <a href="https://www.youtube.com/watch?v=nL_B6LZAsp4" rel="nofollow">https://www.youtube.com/watch?v=nL_B6LZAsp4</a>.<p>The key abstractions we provide are called MCPClient and MCPAgent.<p>MCPClient takes in a set of server configurations, automatically detects the transport type and creates a background task which handles the stream from/to the server.<p>MCPAgent is a combination of the MCPClient, an LLM, and a custom system prompt. It consumes the MCP client by transforming the tools, resources and prompts into model agnostic tools that can be called by the LLM.<p>The library also contains some cool utilities:<p>- secure sandboxed execution of MCP servers (we know the protocol doesn't shine for security)<p>- meta-tools that allow the agent to search over available servers and tools (to avoid context flooding) and connect dynamically to the server it needs (you could create the omnipotent agent with this).<p>Some cool things we did with this:
- write an agent that can use a browser and create/read linear tickets updated with latest information on the internet<p>- write an agent that has access to the metrics of our company to automatically create weekly reports.<p>- I connected an agent to an IKEA curtain I hacked an MCP on to adapt the lighting of my room from images of the lighting situation.<p>- recreated am open source claude code like CLI, with full MCP capability but with custom models and BYOK (<a href="https://github.com/mcp-use/mcp-use-cli">https://github.com/mcp-use/mcp-use-cli</a>).<p>We recently crossed 100,000 download and we are used by many organizations, including NASA!<p>We’d love to hear what you think of it, most importantly how we can improve it! We are happy to answer any questions and look forward to your comments.
Show HN: I built an AI that turns any book into a text adventure game
It's a web app that uses AI to turn any book into a playable text adventure. Your favorite book, but your choices, hence your story. You can even "remix" the genre like playing Dune as a noir detective story.<p>Note: Work in progress. Suggestions are welcome.
Show HN: I built an AI that turns any book into a text adventure game
It's a web app that uses AI to turn any book into a playable text adventure. Your favorite book, but your choices, hence your story. You can even "remix" the genre like playing Dune as a noir detective story.<p>Note: Work in progress. Suggestions are welcome.
Show HN: Companies use AI to take your calls. I built AI to make them for you
We're living in this weird asymmetry where companies use AI to talk to us, but we're still manually dialing them. Companies everywhere are adopting AI voice agents lately. Big retail, family dentist clinics, local pharmacy. This year, I've been in a few calls where it's super natural sounding AI, which has been pretty cool to experience. But then it got me thinking - why are we, the consumers, still the ones making calls if they're using robots for theirs?<p>So I built Piper: basically AI that makes phone calls for you. You tell it what you need (book appointment, check on an order, dispute some charge, whatever), and it handles the entire conversation while you do actual work. Right now it's a web app, Chrome extension is pending approval but soon you'll be able to click any phone number anywhere and just let Piper handle it.<p>Technical stuff that was harder than expected:<p>Latency - every millisecond counts in conversation, had to optimize around kv cache, got it down to ~1000ms to first word over PSTN for telephony, which feels pretty natural<p>Keeping the voice agents on track - built custom context engineering logic that constantly updates the agent's situational awareness, so it knows when it's been transferred, when it's on hold, etc<p>Done ~50 successful calls with early testers so far. Main failures are when they need complex verification or documents. Also had to take down our IVR navigation temporarily :/, found some edge cases that were causing unnecessary transfers but working on fixing that.<p>I really think we're heading toward this world where AI talks to AI for most routine things, and phone calls might be the first real example of this happening at scale!<p>you can check out the a voice demo on our website. <a href="https://pipervoice.com" rel="nofollow">https://pipervoice.com</a>