[echelon]

Rust is simply amazing to do web backend development in. It's the biggest secret in the world right now. It's why people are writing so many different web frameworks and utilities - it's popular, practical, and growing fast.

Writing Rust for web (Actix, Axum) is no different than writing Go, Jetty, Flask, etc. in terms of developer productivity. It's super easy to write server code in Rust.

Unlike writing Python HTTP backends, the Rust code is so much more defect free.

I've absorbed 10,000+ qps on a couple of cheap tiny VPS instances. My server bill is practically non-existent and I'm serving up crazy volumes without effort.

[kstrauser]

I’ve written Python APIs since about 2001 or so. A few weeks ago I used Actix to write a small API server. If you squint and don’t see the braces, it looks an awful lot like a Flask app.

I had fun writing it, learned some new stuff along the way, and ended up with an API that could serve 80K RPS (according to the venerable ab command) on my laptop with almost no optimization effort. I will absolutely reach for Rust+Actix again for my next project.

(And I found, fixed, and PR’d a bug in a popular rate limiter, so I got to play in the broader Rust ecosystem along the way. It was a fun project!)

[boredumb]

I've been experimenting with using Tide, sqlx and askama and after getting comfortable, it's even more ergonomic for me than using golang and it's template/sql librarys. Having compile time checks on SQL and templates in and of itself is a reason to migrate. I think people have a lot of issues with the life time scoping but for most applications it simply isn't something you are explicitly dealing with every day in the way that rust is often displayed/feared (and once you fully wrap your head around what it's doing it's as simple as most other language aspects).

[JamesSwift]

> Writing Rust for web (Actix, Axum) is no different than writing Go, Jetty, Flask, etc. in terms of developer productivity. It's super easy to write server code in Rust.

I would definitely disagree with this after building a micro service (url shortener) in rust. Rust requires you to rethink your design in unique ways, so that you generally cant do things in the 'dumbest way possible' as your v1. I found myself really having to rework my design-brain to fit rusts model to please the compiler.

Maybe once that relearning has occurred you can move faster, but it definitely took a lot longer to write an extremely simple service than I would have liked. And scaling that to a full api application would likely be even slower.

Caveat that this was years ago right when actix 2 was coming out I believe, so the framework was in a high amount of flux in addition to needing to get my head around rust itself.

[collinvandyck76]

> Maybe once that relearning has occurred you can move faster

This has been my experience. I have about a year of rust experience under my belt, working with an existing codebase (~50K loc). I started writing the toy/throwaway programs i normally write, now in rust instead of go halfway through this stretch. Hard to say when it clicked, maybe about 7-8 months through this experience, so that i didn't struggle with the structure of the program and the fights with the borrow checker, but it did to the point where i don't really have to think about it much anymore.

[guitarbill]

I have a similar experience. Was drawn to Rust not because of performance or safety (although it's a big bonus), but because of the tooling and type system. Eventually, it does get easier. I do think that's a poor argument, kind of like a TV show that gets better in season 2. But I can't discount that it's been much nicer to maintain these tools compared to Python. Dependency version updates are much less scary due to actual type checking.

[adamrezich]

Disclaimer: I haven't ever written any serious Rust code, and the last time I even tried to use the language was years ago now.

What is it about Rust that makes it so appealing to people to use for web backend development? From what I can tell, one of the selling points of Rust is its borrow checker/lifetime management system. But if you're making a web backend, then you really only need to care about two lifetimes: the lifetime of the program, and the lifetime of a given request/response. If you want to write a web backend in C, then it's not too difficult to set up a simple system that makes a temporary memory arena for each request/response, and, once the response is sent, marks this memory for reuse (and probably zeroes it, for maximum security), instead of freeing it.

Again, I don't really have any experience with Rust whatsoever, but how does the borrow checker/lifetime system help you with this? It seems to me (as a naïve, outside observer) that these language features would get in the way more than they would help.

[echelon]

> What is it about Rust that makes it so appealing to people to use for web backend development? From what I can tell, one of the selling points of Rust is its borrow checker/lifetime management system.

> Again, I don't really have any experience with Rust whatsoever, but how does the borrow checker/lifetime system help you with this? It seems to me (as a naïve, outside observer) that these language features would get in the way more than they would help.

You're absolutely right that the borrow checker would get in the way. But it's mostly irrelevant in Rust web development. Backend request flow code almost never shares references or changes ownership, so you don't need to think about ownership much in Rust webdev. And since most of the time Rust can infer the lifetimes of variables, you can almost entirely ignore the system and not even annotate lifetimes in your types.

So what you are left with is a language with an incredible type system, extremely modern semantics and ergonomics, zero cost functional abstractions that have no overhead, trait-based OO instead of classes, sum types (Rust enums) and fantastic syntax around matching [1], option and result types (themselves sum types) with fantastic ergonomics, syntax and error handling designed to result in fewer defects in your code, incredible package manager, incredible build system, single binary build targets, the best compiler error messages and lints in the world currently, cross compilation for a wide variety of systems, bare metal performance with no garbage collection.

It's a phenomenal language and offers so much.

And it's insane that you get bare metal / C performance in web code without even having to think about it.

Rust never set out to be a backend web development language, but because the borrow checker disappears when doing web development, you get so many free things from the language that you don't have to pay for. This post [2] explains it pretty well.

[1] One of the best things about the language

[2] https://news.ycombinator.com/item?id=41973845

[adamrezich]

> but because the borrow checker disappears when doing web development, you get so many free things from the language that you don't have to pay for.

Don't you end up paying for it with compile times? Because the borrow checker has to check all your lifetime annotations and do a bunch of work, just to come to the conclusion that your simple two-lifetime (or whatever) setup is in fact valid?

[steveklabnik]

The borrow checker isn't what makes Rust compile slowly. It's largely code generation. Borrow checker stuff appears near-instantly in your editor.

[adamrezich]

Gotcha—thanks for letting me know!

[unrealhoang]

lifetime checking is only done locally (inside function definition), not globally so it's relatively fast.

[nesarkvechnep]

It will probably never replace Elixir as my favourite web technology. For writing daemons though, it's already my favourite.

[manfre]

> I've absorbed 10,000+ qps on a couple of cheap tiny VPS instances.

This metric doesn't convey any meaningful information. Performance metrics need context of the type of work completed and server resources used.

[kelnos]

> Writing Rust for web (Actix, Axum) is no different than writing Go, Jetty, Flask, etc. in terms of developer productivity.

Oh jeez, hard disagree. I absolutely love Rust, but spinning up something in Flask is so so so much easier than in Rust (warp and axum are where I have experience). Certainly some of this is just a part of the learning curve of figuring out a Rust crate you haven't used before. But still, I don't think it's credible that Rust web development is just as productive as the others you mention.