Spring WebClient vs. RestTemplate: Which One Should You Use in 2025?

If you’ve been in the Spring ecosystem for more than a few years, RestTemplate is like an old friend. It’s familiar, it’s synchronous, and let’s be honest—it just works. But if you are starting a new Spring Boot 3.x project in 2025, reaching for that old friend might be the first technical debt you introduce to your codebase.

The debate of Spring WebClient vs RestTemplate isn’t just about syntax preference anymore; it’s about architectural longevity. With the release of Spring Framework 6 and Spring Boot 3, the landscape has shifted significantly. We now have three contenders: the legacy RestTemplate, the reactive powerhouse WebClient, and the new kid on the block, RestClient.

As a lead developer who has migrated dozens of microservices from blocking servlet stacks to reactive streams (and sometimes back again), I want to break down exactly what you should use today, why RestTemplate is technically in maintenance mode, and how to future-proof your API integrations.

The Legacy: Is RestTemplate Dead?

Let’s address the elephant in the room: Is RestTemplate deprecated?

Technically, no. The @Deprecated annotation hasn’t been slapped on it yet. However, the Spring documentation has been explicit for years: RestTemplate is in maintenance mode. This means no new features. If a new HTTP standard emerges or a major performance optimization is discovered, RestTemplate won’t get it. It will only receive minor bug fixes.

Why? Because it is blocking.

RestTemplate follows the “one thread per request” model. When your application makes an external API call, the thread handling that request sits there, doing absolutely nothing, waiting for the response. In 2015, this was fine. In 2025, where we run cloud-native microservices on expensive compute resources, blocking threads is burning money.

When to still use it:

• You are maintaining a legacy application that hasn’t upgraded to Spring Boot 3.
• You have a massive existing codebase of RestTemplate interceptors and error handlers that would take weeks to rewrite.
• Your application makes very infrequent, low-volume external calls where performance is irrelevant.

The Powerhouse: Spring WebClient

Introduced in Spring 5, WebClient was the answer to the blocking problem. It is part of the spring-webflux module and supports fully non-blocking, reactive streams.

When you compare Spring WebClient vs RestTemplate, the performance difference under load is staggering. WebClient uses an event-loop model (similar to Node.js). A small number of threads can handle thousands of concurrent requests because they don’t block. They fire the request and move on, processing the response only when it comes back.

Here is what a standard GET request looks like in WebClient:

WebClient client = WebClient.create("https://api.example.com");

// Asynchronous / Non-blocking
Mono<User> userMono = client.get()
    .uri("/users/{id}", 123)
    .retrieve()
    .bodyToMono(User.class);

// Nothing happens until you subscribe!
userMono.subscribe(user -> System.out.println("Got user: " + user.getName()));

The Learning Curve Issue The problem with WebClient isn’t performance; it’s complexity. If your team isn’t used to Reactive Programming (Monos, Fluxes, flatMap, subscribe), forcing them to migrate RestTemplate to WebClient can kill velocity. Debugging reactive stack traces is arguably one of the most painful experiences in Java development.

However, if you need high throughput—like an API Gateway or a service that aggregates data from 5 different upstream services—WebClient is non-negotiable.

The New Standard: Spring 6 RestClient

This is where 2025 gets interesting. The Spring team realized a gap existed. Developers wanted the clean, fluent syntax of WebClient but didn’t want the complexity of reactive streams. They just wanted a modern, synchronous client to replace RestTemplate.

Enter RestClient.

Introduced in Spring Boot 3.2, RestClient is the official RestTemplate deprecated replacement. It offers the exact same fluent API as WebClient but runs on the Servlet stack (blocking IO) by default.

Why is this a big deal? It means you can write modern code today that looks like this:

RestClient client = RestClient.create("https://api.example.com");

User user = client.get()
    .uri("/users/{id}", 123)
    .retrieve()
    .body(User.class);

Comparison: Performance and Use Cases

Let’s look at the facts.

The Verdict: What Should I Use in 2025?

Here is my rule of thumb for all new backend services:

1. Default Choice: Use Spring RestClient. It is the modern standard for 90% of microservices. It is easy to read, easy to test, and removes the verbosity of RestTemplate while keeping the simplicity of synchronous code.
2. High Performance Choice: Use Spring WebClient only if you are already on the Spring WebFlux stack or if you have specific high-concurrency requirements (e.g., handling 10k+ requests/second with minimal resources).
3. Legacy Choice: Stick with RestTemplate only if you are patching an old app. Do not write new RestTemplate code today.

Moving from cURL to Java

One of the biggest friction points when adopting these new clients is remembering the syntax. We all start testing APIs with cURL in the terminal. Translating a complex cURL command with Auth headers and a JSON body into a fluent WebClient or RestClient chain can be annoying.

You usually end up Googling “how to set bearer token in spring restclient” for the 50th time.

To solve this, I actually use a tool that automates it. You just paste your raw cURL command, and it generates the exact Java code for WebClient, RestClient, or even OkHttp. It handles the messy escaping of JSON strings and header mapping for you.

If you are migrating old code or starting a fresh integration, it saves a ton of time: 👉 Try the cURL to Java Converter here

Final Thoughts

The Java ecosystem moves fast. While it’s tempting to stick to what we know, the shift away from RestTemplate is necessary. The API was designed for a different era of the web. Whether you choose the reactive power of WebClient or the modern simplicity of RestClient, moving to a fluent API will make your code more readable and maintainable.

Stop writing new HttpEntity<> wrappers. Upgrade your client stack, and your future self (debugging production at 3 AM) will thank you.

FAQ: Spring HTTP Clients | Spring WebClient vs RestTemplate

Q: Can I use WebClient in a standard blocking Spring MVC app? A: Yes, you can. You just need to include the spring-boot-starter-webflux dependency. However, you will likely end up calling .block() on every request, which negates the performance benefits but gives you the nice syntax. In this case, RestClient is usually a better fit as it doesn’t require the extra dependency.

Q: Is RestTemplate going to be removed in Spring Boot 4? A: There is no official announcement, but “maintenance mode” is the waiting room for removal. It is unlikely to be removed soon because of how widely it is used, but don’t bet your new project’s 5-year lifespan on it.

Q: How do I handle timeouts in the new RestClient? A: Since RestClient uses an underlying HTTP library (like Apache HttpClient or Jetty), you configure timeouts on the ClientHttpRequestFactory that you pass to the builder. It’s slightly more configuration than WebClient, but very robust.

Q: Which one is better for memory usage? A: WebClient generally has a smaller memory footprint under high load because it doesn’t require a dedicated thread stack (which can be 1MB each) for every waiting request. For low-traffic apps, the difference is negligible.

Q: Can I generate code for these clients automatically? A: Absolutely. Using a cURL to Java converter is the fastest way to get syntactically correct snippets for any of these clients without memorizing the API.