Hacker News: carllerche

Principles for Fast Tokio Applications

carllerche — Mon, 14 Sep 2026 15:27:56 +0000

Article URL: https://dial9-rs.github.io/blog/principles-for-fast-tokio-applications/

Comments URL: https://news.ycombinator.com/item?id=49698607

Points: 120

# Comments: 19

New comment by carllerche in "HTML over WebSockets: real-time SPAs with barely any JavaScript"

carllerche — Wed, 12 Aug 2026 19:28:22 +0000

Topcoat (Rust) is aiming taking this approach as well: https://github.com/tokio-rs/topcoat. The project is still in the early days. It won't require WebSockets, but WebSockets will be an option.

New comment by carllerche in "Topcoat: A framework for building full-stack reactive web apps with Rust"

carllerche — Wed, 22 Jul 2026 16:14:15 +0000

I know the repo was posted here a few days ago (https://news.ycombinator.com/item?id=48952067). The intent was to open the repo at the same time as the blog post, but we ran out of private repo CI credits, so opened it up early and it got posted.

We still wrote the blog post. It provides a bit more context. Feel free to ask questions here.

Topcoat: A framework for building full-stack reactive web apps with Rust

carllerche — Wed, 22 Jul 2026 16:12:32 +0000

Article URL: https://tokio.rs/blog/2026-07-22-announcing-topcoat

Comments URL: https://news.ycombinator.com/item?id=49009053

Points: 8

# Comments: 2

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 05:26:08 +0000

All on the roadmap :) topcoat-ui is already usable with Shadcn components (recent Pr: https://github.com/tokio-rs/topcoat/pull/118) we are still working on pulling in more components.

Re: OpenAPi you want to consume or provide an OpenAPI endpoint? I’m assuming you want to provide one. This is probably on the medium term roadmap after other stuff like UI, tighter ORM integration, email, etc…

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 04:44:12 +0000

> Will have to see if Toasty solves it and whether it lets one query for arbitrary structs and add fields to structs from query results (e.g., in the README example for Toasty, explicitly joining on TODOs and mapping them to a simple field on the User objects as opposed to using ORM `has_many`)

I'm not 100% following. Feel free to ping me in discord (https://discord.gg/tokio) or open an issue on Toasty and we can dig into it. Toasty is also pretty new, but maturing fast.

The other points are valid. There are challenges with extracting params and a type system. This is how topcoat does it: https://docs.rs/topcoat/latest/topcoat/router/attr.path_para...

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 04:26:11 +0000

Topcoat is entirely server rendered. Reactivity is added using attributes and other signals to a JS “runtime” shipped with topcoat. It is a similar idea to htmx/datastar/hotwire where as Leptos uses wasm to run rust in the browser as well as the server, more like nextjs or solidjs

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 04:23:40 +0000

Depends on what you mean by that. Tokio the runtime is lean, and stable. Tokio the org is a collective of devs working on creating and maintaining a full ecosystem for building client and server apps with rust.

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 02:56:53 +0000

The ORM is here: https://github.com/tokio-rs/toasty/. Tighter integration between the two is on the near-term roadmap.

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 02:31:47 +0000

Both Loco and Topcoat aims to be "batteries included" but that means very different things to each project. Topcoat aims to make it easy to build reactive apps without writing any browser JS (or Rust). It uses a similar strategy to Hotwire, HTMX, Datastar, ... It also will default to using the Toasty ORM (though topcoat is modular so you a swap it out). Topcoat is very young and there is a lot more to build.

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 00:52:31 +0000

Don't remind me... I'm old. (I was involved w/ Ruby on Rails in the early days)

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 00:51:55 +0000

I don't take offense from differences in design opinion. The goal of topcoat is to be opinionated and not make everyone happy. And JS libs are a heavy inspiration. They do a lot right and have years of experience in the browser-app space. If you don't like it, Axum aims to be the lower-level HTTP router that anyone can build their own abstractions on top of.

That said, if you are up to it, I would ask that you try using it and provide your thoughts after using it as an issue. Feedback is appreciated.

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 00:26:11 +0000

It's built: github.com/tokio-rs/toasty/, just not tightly integrated yet. That is on the roadmap.

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Sat, 18 Jul 2026 00:03:39 +0000

Yes, that is the goal. Those frameworks have a bit (more than a decade) head start though :) there is a lot to build.

There already is an ORM (https://github.com/tokio-rs/toasty/). You can see a sketch of the roadmap here: https://github.com/tokio-rs/topcoat/issues/104

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Fri, 17 Jul 2026 23:51:02 +0000

Roadmap: https://github.com/tokio-rs/topcoat/issues/104 ORM: github.com/tokio-rs/toasty

It is early, a lot is coming, but you can already build good stuff now.

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Fri, 17 Jul 2026 23:37:42 +0000

Migrations: Done with Toasty (https://github.com/tokio-rs/toasty/) which I intended to be integrated tightly with topcoat. You can see a rough roadmap here, which will be posted: https://github.com/tokio-rs/topcoat/issues/104

Better to ship early and hear what people want though :)

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Fri, 17 Jul 2026 23:15:23 +0000

I think it is highly likely topcoat / toasty will get split out. It is just work, especially since tokio-rs has more CI usage available than the default GitHub org.

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Fri, 17 Jul 2026 22:56:23 +0000

This will (very soon) integrate tighter with the Toasty ORM http://github.com/tokio-rs/toasty/. E.g. tight form -> record flow. We are shipping now though to get usage.

What pain points do you have in the Rust web framework ecosystem? Happy to hear.

New comment by carllerche in "Topcoat: The full full-stack framework for Rust"

carllerche — Fri, 17 Jul 2026 22:54:27 +0000

I didn't expect to see this here yet. We opened up the repo because we ran out of private CI usage. A blog post is coming next week :). Happy to answer questions here though.

One thing to keep in mind, the main reason for Topcoat to exist is that many organizations are already using Rust for infrastructure-level or performance sensitive reasons and often just want to build a web app using the programming language they already use.

New comment by carllerche in "My thoughts on the Bun Rust rewrite"

carllerche — Thu, 09 Jul 2026 14:34:33 +0000

Sounds like Andrew is using the same argument as Bjarne Stroustrup: if you use it right, you don't write bugs. It hasn't really worked out for C++.