Ask HN: What apps are you building? | Hacker News Reader

Ask HN: What apps are you building?

14 pointstotaldude8722 comments

I’m curious what people here are working on lately.

What are you building right now?

Apps, tools, experiments, weird side projects, anything. Would love to see what folks are making.

I'm building a writing app for perfectionists: Reproof (https://reproof.app/)

I've been a writer for over a decade and a half. I'll often rewrite intros and other sections a half-dozen times, or cut quotes and bits that don't quite fit, only later to wonder if an earlier take was better.

I built Reproof to solve this. Every paragraph is versioned, so you can rewrite paragraphs and switch between the takes to see which sounds better. There's a clipping pane on the bottom, to cut things and save them just in case you find a spot to include them later. And there are a bunch of writer-focused features: Write and copy text in either rich text or Markdown, open two documents side-by-side and find/replace between both, selective find/replace to edit only some of the results, command palette to search across everything, daily versioned backups, and more. And lots more to come.

Nearly every other writing app is a digital piece of paper with linear paragraphs. Reproof instead lets you explore the best way to write what you're trying to say.

For my Indian folks, I have just yesterday launched 100% free railway API. Truly free, no strings attached.

The rate-limits are good enough that you can build automations on top. It also comes with MCP server.

https://traintrack.stupidlabs.lol/

The API is open to all, not just in India. Feel free to use.

I have developed an application to manage cards or documents on my mobile phone, which can quickly add authorization watermarks to cards or documents.

And a tool to combine some windows on the computer has also been developed, which can quickly open multiple specified application windows according to the set layout through shortcut keys.

There is also an application that meets my own bookkeeping habits.

If you are interested, you can go to https://bear.best/en/products/ for a look. ^_^

I'm working on xword-pipeline: https://github.com/ekorbia/xword-pipeline

It's a pipeline for generating dense crossword puzzles with a Rust grid fill engine and optional Claude based clue writing and QA processes.

I use it to generate the crossword puzzles on https://wordfuzz.com/. The quality is already good for smaller (5x5 and 9x9) puzzles. I'm working on improvements for larger 15x15 NYT style puzzles.

I'm also working on Ekorbia: https://github.com/ekorbia/ekorbia-desktop. It's a lightweight, MIT licensed, Rust/Tauri desktop app for private local LLMs with a prompt library, chat overlay, ephemeral chat, model comparisons, and folder/RSS/URL watches.

The builds are unsigned but you can build it yourself to avoid the warnings. It has a bundled engine on macOS and requires an OpenAI-compatible server on Windows/Linux. Any feedback would be appreciated.

Nice. I experimented with automated cruciverbalism in the pre-LLM era, and it was a pretty good challenge especially for strict NYT-style crosswords, which maintain aesthetically pleasing symmetry in the puzzle layout.

Looks like we actually exchanged a bit of conversation on this a while back:

https://news.ycombinator.com/item?id=45097346

I think you've done a good job improving on the clue's specificity. As I mentioned in that thread, part of the deep satisfaction of solving a crossword puzzle is the specificity of the answer. It’s far more gratifying to fill in something like “shortwave” than “radio,” or “gallium” instead of just “metal.”

I attempted (over a decade ago at this point) to manage word types using frequency corpuses to help ensure a healthy balance of specific vs filler answers with varying degrees of success...

Small bit of feedback:

On the 9x9 puzzle for Sunday 2026-07-19, one of the three-letter clues was “Cook of Apple fame.” I don’t think this is much of a spoiler, but the answer in the puzzle was WOZ, referring to Steve Wozniak. However I’ve never heard anyone call him a cook. It's made even more confusing because there is a Cook at Apple, aka Tim Cook who took over as CEO after Steve Jobs.

Yes, I tried a while back to use LLMs for both the grid fill and the clue writing but was not able to generate dense puzzles. This pipeline uses a Rust fill engine that fills hundreds of candidate grids using a scored word list.

Thanks for the feedback! I will recheck the clues for that puzzle.

More of a service than an app, my wife and I have been building a paid and private search engine, ad-free, focused on personal search customization. It's called Uruky and it's at https://uruky.com

There's no personal information necessary whatsoever (when you signup, you're assigned a randomly-generated account number, which is what's used to login). You can get 2h of a free trial _if_ you pass a local and private proof-of-work captcha. Then you top-up your account with a payment, and that's it (you can even use crypto via our ProxyStore partnership [1]). No subscription, no data from you is stored in your database.

This month we reached 250 monthly active accounts, _nearing_ 300, but _hopefully_ that'll happen next month. It's much harder without a subscription and social media ads, but we wouldn't want it any other way.

Oh, you also get the source code after 12 months (BUSL -> AGPLv3 in 2 years).

[1]: https://digitalgoods.proxysto.re/en/brand/uruky

I’m working on a 100% faithful adaptation of both QBasic and QuickBasic 4.5 that runs entirely in the browser running on a virtual CPU and hardware abstraction layer. It’s a love letter to everyone who learned to program on Microsoft’s BASIC interpreters in the ’80s and early ’90s. The whole project is fully open source.

The best compliment I’ve received so far is from friends who grew up in the same era I did: when I fullscreen the browser, a few of them assumed it was a virtual machine running the real thing.

I’ve tried hard to capture the spirit of what made QBasic great: built-in IDE help, an interactive, line-by-line interpretive environment, no compilation step, and a fast feedback loop. So far, every program you write in the simulator can be taken to an old 386 and will run exactly the same.

It started out as a bit of a mad scientist experiment, but I’ve already put close to a hundred hours into it.

Silly video demo (take a PEEK - see what I did there?)

https://mordenstar.com/share/qbasic-core-demos

I am also doing something similar here [1]. But I decided to NOT use BASIC as the language. Instead I implemented a new language with more modern features like foreach loops, closures and a less verbose syntax etc. But the focus is still on getting the same IDE experience as QBasic IDE as well as the graphics/sound capabilities as the good old QBasic. Another priority was the availability of built in documentation help with example, which was also a great thing about QBasic.

Not being able to run in the browser is a purposeful choice I made. I want the users to distance themselves from the browser (which I think is an abstraction that is best avoided in the context).

You can take a peek here [2] where you can see a video demo of the IDE loaded with the program for a partial clone of the paratrooper game.

[1] https://hackage.haskell.org/package/spade [2] https://vimeo.com/835347764

Nice.

Mine is definitely more about achieving as close to perfect parity as possible with Microsoft QBASIC (a dog-eared copy of the Microsoft QuickBASIC Compiler book circa 1985 is sitting on my desk right now), but it also dives pretty deeply into the technical decisions behind some of QBasic’s quirks and how it worked with MS‑DOS at the time.

So it’s just as much an educational tool for understanding how BASIC pulled off certain effects. And with the hardware abstraction layer, it also mimics period‑appropriate hardware (386SX, 486DX, etc.).

I took a look at the video. The only thing is that I had a hard time making out what was going on. I could clearly see the green cannon at the bottom, but at the top it just kind of turned into a smeary, artifact-y mess. I don’t know if that was a result of vimeo's compression or what, but I'd consider re‑uploading it at a higher quality.

Working on Personal Tutor, an open-source skill that gives your coding agent a teaching toolkit for building structured, interactive courses that persist locally across sessions. Courses can include lessons, diagrams, quizzes, simulations, runnable coding exercises, glossaries, flashcards, and more.

This project originated out of two complaints that I have with trying to learn with AI: first, it becomes increasingly difficult to revisit previous ideas or concepts as sessions grow longer and second, richer learning experiences are often flattened into a wall of text.

Personal Tutor keeps course, progress, quiz results, coding attempts, etc. together locally so that the agent can see this history when building upon a course. It also ships a library of teaching components, SDK, CLI, and local UI so that agents can spend more tokens on teaching quality rather than component generation.

Would love to hear any feedback!

https://github.com/briannajzhang/personal-tutor

I I am working on:

Guaranteed weight loss (for overweight) and weight gain for (underweight) people, you'll see clear gain or loss within 2-5 weeks. If you are in a calorie surplus, your weight goes up. If you are in a calorie deficit, your weight goes down. MacroCodex uses that relationship to estimate your true maintenance calories over time: https://macrocodex.app/ This can be used to gain or lose weight. You simply need to eat above your maintenance calorie line to gain weight and below it to lose weight. No ads, no subscriptions, no payments, 16k users already.

If you're interested in how it works: https://macrocodex.app/knowledge/rethink/adaptive-tdee/

I'm building Sufleur: a package manager for LLM prompts. You publish Mustache templates as immutable semver versions, and a CLI generates typed TypeScript/Python from them — typed on both the input and output side. The part that's been the most fun to build is inferring input types from the template itself:

  Hi {{user.name}}{{@type string}}

becomes

  { user: { name: string } }

as an input type in the generated code, so prompt changes fail your build instead of your production.

I started it ~a year ago and it died like side projects do. Months later, building something completely different, I caught myself wishing for exactly the tool I'd abandoned, and since then it's completely vacuumed up all my free time.

Repo: https://github.com/sufleur/cli

Working on a rewrite of my free app, Post Haste. The idea is that you setup a template folder structure and configure project files and such as you like, then when you want to create a new project you enter some parameters like project name and ID and it copies the structure across.

There’s more to it than that of course, and you can use variables, folder breaks, etc, to fully customize how it sets up the project.

It’s great for ensuring consistency in project structures, which is especially useful in a larger company with a lot of employees. It was originally created for video editors but it’s agnostic and can be used for any type of project.

Existing app is here: https://www.digitalrebellion.com/posthaste

https://github.com/prettydiff/aphorio

* Dashboard for docker and web servers

* The web servers serve WebSockets and http from the same ports

* The web servers provide simple proxies and can even proxy TLS connections over non-TLS intermediaries

* Provides resource graphs for each docker container and web servers provide simple

* Lists all machine processes, services, user accounts, ports by tcp or udp, hardware information, and more

* Provides tools for testing http and WebSocket connections

* Provides remote shells allowing the user to choose from all installed shells on the machine

* supports both Linux and Windows

* Is just written in TypeScript and designed for high performance

I built a mini frontend framework with components, state management and backend data fetching.

It is designed to have a minimal learning curve, and has faster performance than React due to the use of web components.

I've been working on https://dynobox.xyz which is a local test runner for agents skills.

I was working on an agentic payments (MPP) powered service and had a hard time getting consistent behavior from my skill.md i was hoping to distribute. so like usually, one project let to another...

If anyone wants to try it out and has feedback I'd love to hear!

We are building an AI Agent Designer web app-Craftsman Agent which can turn prompts into ready to use 3D/2D design, such as a Tesla car wrap, a Perler Beads Pattern, etc. You can use "Generate a blue and white yacht", "Generate a Argentina Football Team Theme Car wrap or Perler Beads Pattern" to generate lego 3D blueprint, step by step assembly charts, etc.

I forgot to leave the Craftsman Agent site link, and just append it here: https://craftsman-agent.aiagenta2z.com/app.

Now it supports various app to turn ideas(prompt/images) to design blueprint and finished products: 3D Generator, Lego Build, Minecraft Voxel Builder, 2D Perler Beads Pindou Builder. Would like to get your feedback!

I have created a whitelist only email service at Supertopsecret.com. Only addresses the user provides can get into the inbox. All else is blocked. Landing page is a spy theme and would be interested if people think it's too sarcastic/off putting. Thank you. Detailed comments can go to hq@supertopsecret.com (which I set up to be non-whitelist only).

Im trying to finish an idea ive had for years. Meal Planning but using the computer & constraints to help people/families truly reduce decision fatigue and "mental load".

In an ideal world it would be good enough to put meal planning on autopilot.

Getting pretty close to public beta if anyone is interested.

I work on FluidCAD on my free time. I published v0.0.40 last weekend with some big updates.

https://github.com/Fluid-CAD/FluidCAD

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