Rust – my first impressions

Building High-Performance Web Services with Rust


Rust, a systems programming language developed by Mozilla, has gained considerable popularity for its focus on safety, performance, and concurrency. While Rust has found success in various domains, it’s also a compelling choice for web back-end development. In this blog post, we’ll explore how Rust can be used to build high-performance web services, specifically by fetching records from a PostgreSQL database and returning them as JSON.

Fetching Data from PostgreSQL

Rust’s ecosystem offers libraries like tokio-postgres that facilitate connecting to PostgreSQL databases. By leveraging asynchronous programming with tokio, we can efficiently fetch records. The example code demonstrates establishing a connection, executing a query, and converting the resulting rows into Rust structs.

Serializing to JSON

With the help of the serde and serde_json crates, we effortlessly serialize our fetched data into JSON format. Rust’s strong type system ensures data integrity and eliminates common serialization errors. In the provided example, the warp crate is used to build a basic web service route that invokes the data fetching function and returns the serialized JSON as a response.

Benefits of Rust for Web Back-End Development

  1. Safety: Rust’s ownership and borrowing model prevents common memory-related bugs at compile-time, reducing the risk of security vulnerabilities and crashes.
  2. Performance: Rust achieves performance comparable to C and C++, making it ideal for high-performance web services. Zero-cost abstractions and low-level control contribute to its efficiency.
  3. Concurrency: Rust’s design promotes safe concurrency through concepts like ownership, lifetimes, and async/await syntax. This allows developers to write scalable and efficient code for handling concurrent web requests.


Rust’s unique combination of safety, performance, and concurrency makes it a powerful language for web back-end development. By showcasing how to fetch records from a PostgreSQL database and return them as JSON in a web service, we’ve demonstrated Rust’s suitability for building high-performance web applications. Although Rust has a learning curve, investing time in mastering it can yield significant benefits in terms of security, performance, and developer productivity.

Some code Example

Here is an example of how to fetch a record from PostgreSQL and return it as JSON for a web service in Rust:

use std::{env, error::Error};

use actix_web::{get, web, App, HttpResponse, HttpServer};
use postgres::{Client, NoTlsMode};

struct User {
    id: i32,
    name: String,

async fn get_user(db: &Client, id: i32) -> Result<User, Box<dyn Error>> {
    let user = db
        .query("SELECT * FROM users WHERE id = $1", &[&id])


async fn users(id: web::Path<i32>, db: web::Data<Client>) -> HttpResponse {
    let user = get_user(&db, id.into_inner()).await?;


async fn main() -> Result<(), Box<dyn Error>> {
    let database_url = env::var("DATABASE_URL").expect("DATABASE_URL not set");

    let mut client = Client::new(database_url, NoTlsMode).unwrap();

    HttpServer::new(|| App::new().service(users))


This code will create a web service that can be used to fetch a user from PostgreSQL by their ID. The service will return the user as JSON.

To use the service, you can make a GET request to This will return the user with the ID 123.

Here is an example of the JSON that will be returned:

    "id": 123,
    "name": "John Doe"

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