Ask HN: What are you working on? (September 2026)

Spending almost all of my time working on DNTLS (https://dntls.net/). Yesterday I was able to create secure mTLS tunnels over IPv6 for direct P2P to my co-founder's desktop in SE Asia (I'm in the US). He was able to load a website I was hosting locally on my machine. I also tested coordinating through a relay to avoid publishing my public IP and sending all traffic through the relay to hide my IP entirely. We more or less recreated the "old" internet in a way except everything is mTLS and E2E encrypted.

Lots of things really:

1. Aetheris: geometry CAD kernel, https://github.com/yuechen-li-dev/Aetheris/.

Full code CAD capability with big coverage already and some functionalities that even OpenCascade/Parasolid/ACIS doesn't have, full sheet metal module, programmable part assembly, analytical fillets/chamfers, mathematical knots, auto-route for piping, built-in finite element analysis, etc. Had Astra make an improved version of the V8 demo that was going around on LinkedIn, so it can do general hard surface modeling pretty well too, turn all the Astra demo prowess into reusable capabilities/templates. The DSL is human writable too, so give it a try if you want. https://aetheris-editable-v8.yuechenli.workers.dev/

2. Concept language: https://github.com/yuechen-li-dev/Concept

I've said before that Carbon isn't a real programming language, never mind a successor to C++, so I decided to put my money where my mouth is. The idea of it is to be more TypeScript to C++'s JavaScript and to generalize C++20 concepts from template constraints to what C++26 is doing with contracts, and bring the equivalent of Rust's borrow checker to be opt-in by default instead of opt-out, fast compile time, in a syntax that C++ users are already familiar with (`const auto` instead of `let` for example) as well as templates and comptime. Language is done-ish, not self hosted yet, still compiles to C11, kernel and allocator libraries are finished, currently working on the scheduler right now.

3. Copeland TS, https://github.com/yuechen-li-dev/copeland

TypeScript for .NET without all the weirdness of Javascript, with full Nuget and NPM inter-op, Rust style exhaustive `match`, templates, etc. It's actually weird how much cleaned up TypeScript ended up looking like cleaned up C++. Compiles to JS, C#, WASM via Blazor WebAssembly, and SPIR-V via HLSL/DXC, and runs on V8 for JS and RyuJIT/NativeAOT for C#. The conclusion is that RyuJIT ended up being ~2x faster than V8 JS in hot loops but the cold startup time is higher, so replacing JS for UI really isn't worth it. Comes with full UI layout system, Vulkan renderer, and game/app runtime, but those are still pretty rough.

All those things I use once in a while, I put them on one place without ads or bs. Optimized for usability, not impressions or whatever.

https://sfw.tools

If there's a tool you'd like to see there, let me know and I'll add it.

This is very niche, only for people who do astrophotography or astronomers, mostly because of the required specialized file format.

I have slowly built out a set of tools for asteroid orbits and photometry (measuring how bright stars/asteroids are).

It is very rough still (Desktop only), and it only supports the FITs file standard.

https://www.astrometry.space/

Basically it is a full professional grade telescope processing pipeline in your browser. It does 2 queries to some custom databases to identify known asteroids and stars, but all image processing and calculations are done in the browser. This means the backend is pretty tiny. That said it is running on an old box in my closet, so queries may take a while if it gets hammered.

I built it since I have worked with quite a few astronomers over the past 4 years and I keep watching them do the same steps, purely built to make my friends lives easier. I wrote it all in rust and managed to compile it into wasm. With some help from fable as I am not a frontend guy at all, I built it into a small website.

Some of the code is public, the orbital mechanics code I wrote while I worked at Caltech. Which is being used on SphereX, NEO Surveyor, and the Roman telescopes to identify known asteroids. https://github.com/dahlend/kete

I'm working on CLI/TUI tool that stores all code collaboration (issues, PRs, etc) in git itself. It lets you publish repositories as static sites to S3 buckets and use them as remotes:

https://gitsocial.org/ https://github.com/gitsocial-org/gitsocial