The best Hacker News stories from Show from the past day
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Show HN: String Flux – Simplify everyday string transformations for developers
I built <a href="https://stringflux.io/" rel="nofollow">https://stringflux.io/</a> to make everyday string transformations a little less painful. It’s similar to CyberChef in the sense that it supports multiple string operations, but with a cleaner, more focused UI and smart suggestions based on your input.<p>You can also chain transformations — for example: decode base64 string which was base64 encoded from minified json → then json format (pretty-print) it — all in one flow. This is helpful when dealing with complex or nested strings, like encoded API responses or log data, where you need to apply multiple steps to make the content readable.<p>The idea came from the frustration of jumping between different tools just to handle common string tasks.<p>There’s a short GIF demo in the GitHub README: <a href="https://github.com/stringflux/stringflux">https://github.com/stringflux/stringflux</a><p>Would love to hear your thoughts and feedback!
Show HN: Container Use for Agents
Show HN: Lambduck, a Functional Programming Brainfuck
What if Brainfuck was less like C and more like Scheme?<p>The interpreter implemetation is pretty bad. It's not very fast, it's not very good, and it's probably not very correct. But maybe there's some vaguely interesting programs you could write with it!<p>For example, the Y combinator:<p><pre><code> λf. (λx. f (x x)) (λx. f (x x))
</code></pre>
is written as:<p><pre><code> \` \`1 `0 0 \`1 `0 0</code></pre>
Show HN: AI game animation sprite generator
I tried to build AI game animation generator last year ( <a href="https://news.ycombinator.com/item?id=40395221">https://news.ycombinator.com/item?id=40395221</a>), a lot of people were interested, but it failed, mainly because the technology was not good enough.<p>1 year passed, there were a lot of developments in video/image generation. I tried it again, I think it works super well now. Actually beyond my expectation.<p>You can generate all kinds of game character animation sprites with only 1 image.<p>1, upload your image of your character
2, choose the action you want
3, generate!<p>Support basic actions like Run, Jump, Punch and complicated ones like: Shoryuken, Spinning kick, etc.<p>High quality sprite sheet will be directly generated to use in Unity and any game engine.<p>If you are an indie game developer, you don't need to high an artist or animator to develop you game.<p>For studios, it's 10x cost saving and 10x efficiency as no more creating animations for 100 NPCs 100 times.<p>Please check it out, looking forward to your feedback!
Show HN: iOS Screen Time from a REST API
We're Oliver and Royce and we're the founders of Clearspace. We build tools to help people reduce their screen time (here’s us two years ago: <a href="https://news.ycombinator.com/item?id=35888644">https://news.ycombinator.com/item?id=35888644</a>)<p>We get all kinds of requests from users for ways they'd like to use their screen time data.<p>- “Auto-donate $x to charity every time I exceed a limit or try to bypass it”<p>- “My 75 Hard group has a screen time requirement, can we set up group visibility?”<p>- “Let my personal agent know if it’s a good time to tackle things on my todo list”<p>- “Auto-report large deviations in my screen time to my therapist “<p>We aren't able to build for all of them, so we're releasing this API.<p>This is the first time iOS Screen Time is accessible on the web. Apple doesn’t expose it, but since we measure it ourselves, we can - via UI or API. We're launching this API so developers can build all these tools and more. Our goal is to enable more solutions to what we believe is the biggest problem in the world - the misalignment of human attention and intention in the digital world.<p>Here's a quick demo of setting up and using the API: <a href="https://drive.google.com/file/d/1QahETj3xaaIsn0JiNbuqvTaSLdxo-eTu/view?usp=sharing" rel="nofollow">https://drive.google.com/file/d/1QahETj3xaaIsn0JiNbuqvTaSLdx...</a>
Show HN: iOS Screen Time from a REST API
We're Oliver and Royce and we're the founders of Clearspace. We build tools to help people reduce their screen time (here’s us two years ago: <a href="https://news.ycombinator.com/item?id=35888644">https://news.ycombinator.com/item?id=35888644</a>)<p>We get all kinds of requests from users for ways they'd like to use their screen time data.<p>- “Auto-donate $x to charity every time I exceed a limit or try to bypass it”<p>- “My 75 Hard group has a screen time requirement, can we set up group visibility?”<p>- “Let my personal agent know if it’s a good time to tackle things on my todo list”<p>- “Auto-report large deviations in my screen time to my therapist “<p>We aren't able to build for all of them, so we're releasing this API.<p>This is the first time iOS Screen Time is accessible on the web. Apple doesn’t expose it, but since we measure it ourselves, we can - via UI or API. We're launching this API so developers can build all these tools and more. Our goal is to enable more solutions to what we believe is the biggest problem in the world - the misalignment of human attention and intention in the digital world.<p>Here's a quick demo of setting up and using the API: <a href="https://drive.google.com/file/d/1QahETj3xaaIsn0JiNbuqvTaSLdxo-eTu/view?usp=sharing" rel="nofollow">https://drive.google.com/file/d/1QahETj3xaaIsn0JiNbuqvTaSLdx...</a>
Show HN: Ask-human-mcp – zero-config human-in-loop hatch to stop hallucinations
While building my startup i kept running into the issue where ai agents in cursor create endpoints or code that shouldn't exist, hallucinates strings, or just don't understand the code.<p>ask-human-mcp pauses your agent whenever it’s stuck, logs a question into ask_human.md in your root directory with answer: PENDING, and then resumes as soon as you fill in the correct answer.<p>the pain:<p>your agent screams out an endpoint that never existed
it makes confident assumptions and you spend hours debugging false leads<p>the fix:<p>ask-human-mcp gives your agent an escape hatch. when it’s unsure, it calls ask_human(), writes a question into ask_human.md, and waits. you swap answer: PENDING for the real answer and it keeps going.<p>some features:<p>- zero config: pip install ask-human-mcp + one line in .cursor/mcp.json → boom, you’re live
- cross-platform: works on macOS, Linux, and Windows—no extra servers or webhooks.
- markdown Q\&A: agent calls await ask_human(), question lands in ask_human.md with answer: PENDING. you write the answer, agent picks back up
- file locking & rotation: prevents corrupt files, limits pending questions, auto-rotates when ask_human.md hits ~50 MB<p>the quickstart<p>pip install ask-human-mcp
ask-human-mcp --help<p>add to .cursor/mcp.json and restart:
{
"mcpServers": {
"ask-human": { "command": "ask-human-mcp" }
}
}<p>now any call like:<p>answer = await ask_human(
"which auth endpoint do we use?",
"building login form in auth.js"
)<p>creates:<p>### Q8c4f1e2a
ts: 2025-01-15 14:30
q: which auth endpoint do we use?
ctx: building login form in auth.js
answer: PENDING<p>just replace answer: PENDING with the real endpoint (e.g., `POST /api/v2/auth/login`) and your agent continues.<p>link:<p>github -> <a href="https://github.com/Masony817/ask-human-mcp">https://github.com/Masony817/ask-human-mcp</a><p>feedback:<p>I'm Mason a 19yo solo-founder at Kallro. Happy to hear any bugs, feature requests, or weird edge cases you uncover - drop a comment or open an issue!
buy me a coffee -> coff.ee/masonyarbrough
Show HN: Ask-human-mcp – zero-config human-in-loop hatch to stop hallucinations
While building my startup i kept running into the issue where ai agents in cursor create endpoints or code that shouldn't exist, hallucinates strings, or just don't understand the code.<p>ask-human-mcp pauses your agent whenever it’s stuck, logs a question into ask_human.md in your root directory with answer: PENDING, and then resumes as soon as you fill in the correct answer.<p>the pain:<p>your agent screams out an endpoint that never existed
it makes confident assumptions and you spend hours debugging false leads<p>the fix:<p>ask-human-mcp gives your agent an escape hatch. when it’s unsure, it calls ask_human(), writes a question into ask_human.md, and waits. you swap answer: PENDING for the real answer and it keeps going.<p>some features:<p>- zero config: pip install ask-human-mcp + one line in .cursor/mcp.json → boom, you’re live
- cross-platform: works on macOS, Linux, and Windows—no extra servers or webhooks.
- markdown Q\&A: agent calls await ask_human(), question lands in ask_human.md with answer: PENDING. you write the answer, agent picks back up
- file locking & rotation: prevents corrupt files, limits pending questions, auto-rotates when ask_human.md hits ~50 MB<p>the quickstart<p>pip install ask-human-mcp
ask-human-mcp --help<p>add to .cursor/mcp.json and restart:
{
"mcpServers": {
"ask-human": { "command": "ask-human-mcp" }
}
}<p>now any call like:<p>answer = await ask_human(
"which auth endpoint do we use?",
"building login form in auth.js"
)<p>creates:<p>### Q8c4f1e2a
ts: 2025-01-15 14:30
q: which auth endpoint do we use?
ctx: building login form in auth.js
answer: PENDING<p>just replace answer: PENDING with the real endpoint (e.g., `POST /api/v2/auth/login`) and your agent continues.<p>link:<p>github -> <a href="https://github.com/Masony817/ask-human-mcp">https://github.com/Masony817/ask-human-mcp</a><p>feedback:<p>I'm Mason a 19yo solo-founder at Kallro. Happy to hear any bugs, feature requests, or weird edge cases you uncover - drop a comment or open an issue!
buy me a coffee -> coff.ee/masonyarbrough
Show HN: Claude Composer
Central feature is a something like "yolo mode" but with fine grained controls over how yolo you're feeling. Also makes it easy to use "presets" of tools and permissions.<p>Let me know if you have any questions and feel free to contact me on X at <a href="https://x.com/possibilities" rel="nofollow">https://x.com/possibilities</a>
Show HN: Claude Composer
Central feature is a something like "yolo mode" but with fine grained controls over how yolo you're feeling. Also makes it easy to use "presets" of tools and permissions.<p>Let me know if you have any questions and feel free to contact me on X at <a href="https://x.com/possibilities" rel="nofollow">https://x.com/possibilities</a>
Show HN: I made a 3D SVG Renderer that projects textures without rasterization
Show HN: I made a 3D SVG Renderer that projects textures without rasterization
Show HN: ClickStack – Open-source Datadog alternative by ClickHouse and HyperDX
Hey HN! Mike & Warren here from HyperDX (now part of ClickHouse)! We’ve been building ClickStack, an open source observability stack that helps you collect, centralize, search/viz/alert on your telemetry (logs, metrics, traces) in just a few minutes - all powered by ClickHouse (Apache2) for storage, HyperDX (MIT) for visualization and OpenTelemetry (Apache2) for ingestion.<p>You can check out the quick start for spinning things up in the repo here: <a href="https://github.com/hyperdxio/hyperdx">https://github.com/hyperdxio/hyperdx</a><p>ClickStack makes it really easy to instrument your application so you can go from bug reports of “my checkout didn’t go through” to a session replay of the user, backend API calls, to DB queries and infrastructure metrics related to that specific request in a single view.<p>For those that might be migrating from Very Expensive Observability Vendor (TM) to something open source, more performant, and doesn’t require extensive culling of retention limits and sampling rates - ClickStack gives a batteries-included way of starting that migration journey.<p>For those that aren’t familiar with ClickHouse, it’s a high performance database that has already been used by companies such as Anthropic, Cloudflare, and DoorDash to power their core observability at scale due to its flexibility, ease of use, and cost effectiveness. However, this required teams to dedicate engineers to building a custom observability stack, where it’s difficult to not only get their telemetry data easily into ClickHouse but also struggling without a native UI experience.<p>That’s why we’re building ClickStack - we wanted to bundle an easy way to get started ingesting your telemetry data whether it’s logs & traces from Node.js or Ruby to metrics from Kubernetes or your bare metal infrastructure. Just as important we wanted our users to enjoy a visualization experience that allowed users to quickly search using a familiar lucene-like search syntax (similar to what you’d use in Google!). We recognise though, that a SQL mode is needed for the most complex of queries. We've also added high cardinality outlier analysis by charting the delta between outlier and inlier events - which we've found really helpful in narrowing down causes of regressions/anomalies in our traces as well as log patterns to condense down clusters of similar logs.<p>We’re really excited about the roadmap ahead in terms of improving ClickStack as a product and the ClickHouse core database to improve observability. Would love to hear everyone’s feedback and what they think!<p>Spinning up a container is pretty simple: `docker run -p 8080:8080 -p 4317:4317 -p 4318:4318 docker.hyperdx.io/hyperdx/hyperdx-all-in-one`
In browser live demo (no sign ups or anything silly, it runs fully in your browser!): <a href="https://play.hyperdx.io/" rel="nofollow">https://play.hyperdx.io/</a> Landing Page: <a href="https://clickhouse.com/o11y" rel="nofollow">https://clickhouse.com/o11y</a> Github Repo: <a href="https://github.com/hyperdxio/hyperdx">https://github.com/hyperdxio/hyperdx</a>
Discord community: <a href="https://hyperdx.io/discord" rel="nofollow">https://hyperdx.io/discord</a>
Docs: <a href="https://clickhouse.com/docs/use-cases/observability/clickstack/getting-started" rel="nofollow">https://clickhouse.com/docs/use-cases/observability/clicksta...</a>
Show HN: ClickStack – Open-source Datadog alternative by ClickHouse and HyperDX
Hey HN! Mike & Warren here from HyperDX (now part of ClickHouse)! We’ve been building ClickStack, an open source observability stack that helps you collect, centralize, search/viz/alert on your telemetry (logs, metrics, traces) in just a few minutes - all powered by ClickHouse (Apache2) for storage, HyperDX (MIT) for visualization and OpenTelemetry (Apache2) for ingestion.<p>You can check out the quick start for spinning things up in the repo here: <a href="https://github.com/hyperdxio/hyperdx">https://github.com/hyperdxio/hyperdx</a><p>ClickStack makes it really easy to instrument your application so you can go from bug reports of “my checkout didn’t go through” to a session replay of the user, backend API calls, to DB queries and infrastructure metrics related to that specific request in a single view.<p>For those that might be migrating from Very Expensive Observability Vendor (TM) to something open source, more performant, and doesn’t require extensive culling of retention limits and sampling rates - ClickStack gives a batteries-included way of starting that migration journey.<p>For those that aren’t familiar with ClickHouse, it’s a high performance database that has already been used by companies such as Anthropic, Cloudflare, and DoorDash to power their core observability at scale due to its flexibility, ease of use, and cost effectiveness. However, this required teams to dedicate engineers to building a custom observability stack, where it’s difficult to not only get their telemetry data easily into ClickHouse but also struggling without a native UI experience.<p>That’s why we’re building ClickStack - we wanted to bundle an easy way to get started ingesting your telemetry data whether it’s logs & traces from Node.js or Ruby to metrics from Kubernetes or your bare metal infrastructure. Just as important we wanted our users to enjoy a visualization experience that allowed users to quickly search using a familiar lucene-like search syntax (similar to what you’d use in Google!). We recognise though, that a SQL mode is needed for the most complex of queries. We've also added high cardinality outlier analysis by charting the delta between outlier and inlier events - which we've found really helpful in narrowing down causes of regressions/anomalies in our traces as well as log patterns to condense down clusters of similar logs.<p>We’re really excited about the roadmap ahead in terms of improving ClickStack as a product and the ClickHouse core database to improve observability. Would love to hear everyone’s feedback and what they think!<p>Spinning up a container is pretty simple: `docker run -p 8080:8080 -p 4317:4317 -p 4318:4318 docker.hyperdx.io/hyperdx/hyperdx-all-in-one`
In browser live demo (no sign ups or anything silly, it runs fully in your browser!): <a href="https://play.hyperdx.io/" rel="nofollow">https://play.hyperdx.io/</a> Landing Page: <a href="https://clickhouse.com/o11y" rel="nofollow">https://clickhouse.com/o11y</a> Github Repo: <a href="https://github.com/hyperdxio/hyperdx">https://github.com/hyperdxio/hyperdx</a>
Discord community: <a href="https://hyperdx.io/discord" rel="nofollow">https://hyperdx.io/discord</a>
Docs: <a href="https://clickhouse.com/docs/use-cases/observability/clickstack/getting-started" rel="nofollow">https://clickhouse.com/docs/use-cases/observability/clicksta...</a>
Show HN: Air Lab – A portable and open air quality measuring device
Hi HN!<p>I’ve been working on an air quality measuring device called Air Lab for the past three years. It measures CO2, temperature, relative humidity, air pollutants (VOC, NOx), and atmospheric pressure. You can log and analyze the data directly on the device — no smartphone or laptop needed.<p>To better show what the device can do and how it feels like, I spent the past week developing a web-based simulator using Emscripten. It runs the stock firmware with most features available except for networking. Check it out and let me know what you think!<p>The firmware will be open-source and available once the first batch of devices ships. We’re currently finishing up our crowdfunding campaign on CrowdSupply. If you want to get one, now is the time to support the project: <a href="https://www.crowdsupply.com/networked-artifacts/air-lab" rel="nofollow">https://www.crowdsupply.com/networked-artifacts/air-lab</a><p>We started building the Air Lab because most air quality measuring devices we found were locked-down or hard to tinker with. Air quality is a growing concern, and we’re hoping a more open, playful approach can help make the topic more accessible. It is important to us that there is a low bar for customizing and extending the Air Lab. Until we ship, we plan to create rich documentation and further tools, like the simulator, to make this as easy as possible.<p>The technical: The device is powered by the popular ESP32S3 microcontroller, equipped with a precise CO2, temperature, and relative humidity sensor (SCD41) as well as a VOC/NOx (SGP41) and atmospheric pressure sensor (LPS22). The support circuitry provides built-in battery charging, a real-time clock, an RGB LED, buzzer, an accelerometer, and capacitive touch, which makes Air Lab a powerful stand-alone device. The firmware itself is written on top of esp-idf and uses LVGL for rendering the UI.<p>If you seek more high-level info, here are also some videos covering the project:
- <a href="https://www.youtube.com/watch?v=oBltdMLjUyg" rel="nofollow">https://www.youtube.com/watch?v=oBltdMLjUyg</a> (Introduction)
- <a href="https://www.youtube.com/watch?v=_tzjVYPm_MU" rel="nofollow">https://www.youtube.com/watch?v=_tzjVYPm_MU</a> (Product Update)<p>Would love your feedback — on the device, hardware choices, potential use cases, or anything else worth improving. If you want to get notified on project updates, subscribe on Crowd Supply.<p>Happy to answer any questions!
Show HN: Gradle plugin for faster Java compiles
Hey HN,<p>We've written a pretty cool Gradle plugin I wanted to share.<p>It turns out if you native-image the Java and Kotlin compilers, you can experience a serious gain, especially for "smaller" projects (under 10,000 classes).<p>By compiling the compiler with native image, JIT warmup normally experienced by Gradle/Maven et al is skipped. Startup time is extremely fast, since native image seals the heap into the binary itself. The native version of javac produces identical outputs from inputs. It's the same exact code, just AOT-compiled, translated to machine code, and pre-optimized by GraalVM.<p>Of course, native image isn't optimal in all cases. Warm JIT still outperforms NI, but I think most projects <i>never hit</i> fully warmed JIT through Gradle or Maven, because the VM running the compiler so rarely survives for long enough.<p>Elide (the tool used by this plugin) also supports fetching Maven dependencies. When active, it prepares a local m2 root where Gradle can find your dependencies already on-disk when it needs them. Preliminary benchmarking shows a 100x+ gain since lockfiles prevent needless re-resolution and native-imaging the resolver results in a similar gain to the compiler.<p>We (the authors) are very much open to feedback in improving this Gradle plugin or the underlying toolchain. Please, let us know what you think!
Show HN: App.build, an open-source AI agent that builds full-stack apps
Show HN: PinSend – Share text between devices using a PIN(P2P, no login)
Hi HN,<p>I built [PinSend](<a href="https://pinsend.app" rel="nofollow">https://pinsend.app</a>) — a free web app for instantly sharing text between devices, using a simple 6-character PIN.<p>- No login, no account, no install.
- Peer-to-peer WebRTC transfer (no server relay, no cloud).
- Cross-platform: works on any modern browser.<p>I built PinSend for myself while developing web apps—I was always copying ngrok links and sending error logs between my laptop and mobile devices. I wanted a frictionless, instant way to move links and text between anything.<p>*Demo:*
1. Open <a href="https://pinsend.app" rel="nofollow">https://pinsend.app</a> on your phone & laptop
2. Paste or type some text and hit "Send", enter the PIN on the other device
3. Instant sync!
4. No more emailing or Whatsapping notes to yourself<p>Would love feedback!
Show HN: Hacker News historic upvote and score data
Hi yall!<p>I've been using hacker news for a while but one of the things I started wanting recently was the ability to have alerts for any stories I post.<p>The thing that pushed me over the edge was Hackclub's shipwrecked <a href="https://shipwrecked.hackclub.com/" rel="nofollow">https://shipwrecked.hackclub.com/</a> (hackathon in the boston bay for anyone that can make 4 projects over the summer and get at least one of them to go viral). One of the options for "going viral" was to get to the front page of hacker news but I was constantly scared that I would miss it getting on there lol so I whipped up a quick slackbot to send alerts to a channel. It was dead simple but it did work.<p>Once I had the bot I realized I could do wayyyy more with the data I was collecting so I decided to add some historical data initially thinking I would generate graphs and then embed them in the message but decided to quickly try using Bun.serve to host a quick dashboard mainly since I wanted to see how the developer experience was.
Spoiler it is amazing. I've gotten really inspired by web components and the idea of only using universally supported `html`, `css`, and `js`. Bun results in an amazingly nice developer experience where you can just import the `index.html` and assign it to your root route and be done. Sorry for shilling about bun but it truly was one of my favorite parts of building this besides drizzle.<p>The dashboard has a graph of the points earned and position on the leaderboard over time (updated every 5 minutes) and then the expected stats like peak points, peak position, author, and comment count.<p>Also btw all the code is open source ofc on both my tangled repo (<a href="https://tangled.sh/@dunkirk.sh/hn-alerts" rel="nofollow">https://tangled.sh/@dunkirk.sh/hn-alerts</a>) as well as a github repo (<a href="https://github.com/taciturnaxolotl/hn-alerts">https://github.com/taciturnaxolotl/hn-alerts</a>) and you can try the hosted version at <a href="https://hn.dunkirk.sh" rel="nofollow">https://hn.dunkirk.sh</a>
I'm planning to add the ability to just install the slackbot to any workspace and have workspace specific leaderboards but that will require a bit of refactoring and probably abandoning the slack-edge package.<p>Also you can view specific item's data by simply replacing news.yc.com with hn.dunkirk.sh like: <a href="https://hn.dunkirk.sh/item?id=44115853" rel="nofollow">https://hn.dunkirk.sh/item?id=44115853</a>
Show HN: GPT image editing, but for 3D models
Hey HN!<p>I’m Zach one of the co-founders of Adam (<a href="https://www.adamcad.com">https://www.adamcad.com</a>). We're building AI-powered tools for CAD and 3D modeling [1].<p>We’ve recently been exploring a new way to bring GPT-style image editing directly into 3D model generation and are excited to showcase this in our web-app today. We’re calling it creative mode and are intrigued by the fun use cases this could create by making 3D generation more conversational!<p>For example you can put a prompt in such as “an elephant” then follow it up by “have it ride a skateboard” and it preserves the context, identity and maintains consistency with the previous model. We believe this lends itself better to an iterative design process when prototyping creative 3D assets or models for printing.<p>We’re offering everyone 10 free generations to start (ramping up soon!). Here’s a short video explaining how it works: <a href="https://www.loom.com/share/cf9ab91375374a4f93d6cc89619a043b" rel="nofollow">https://www.loom.com/share/cf9ab91375374a4f93d6cc89619a043b</a><p>We’d also love you to try our parametric mode (free!) which uses LLMs to create a conversational interface for solid modeling as touched on in a recent HN thread [2]. We are leveraging the code generation capabilities of these models to generate OpenSCAD code (an open-source script based CAD) and are surfacing the variables as sliders the user can toggle to adjust their design. We hope this can give a glimpse into what it could be like to “vibe-CAD”. We will soon be releasing our results on Will Patrick's Text to CAD eval [3] and adding B-rep compatible export!<p>We’d love to hear what you think and where we should take this next :)<p>[1]<a href="https://x.com/zachdive/status/1882858765613228287" rel="nofollow">https://x.com/zachdive/status/1882858765613228287</a><p>[2]<a href="https://news.ycombinator.com/item?id=43774990">https://news.ycombinator.com/item?id=43774990</a><p>[3]<a href="https://willpatrick.xyz/technology/2025/04/23/teaching-llms-how-to-solid-model.html" rel="nofollow">https://willpatrick.xyz/technology/2025/04/23/teaching-llms-...</a>