JQuickCurl vs OkHttp vs RestTemplate vs OpenFeign: A Honest Comparison for Backend Engineers

#java #restapi #rest #api

Choosing an HTTP client is a "boring but expensive" decision: it touches every downstream integration you own. OkHttp, Spring's RestTemplate, OpenFeign, and now curl-driven JQuickCurl all work — the real question is who should write and maintain your request definitions. This post compares the four on the dimensions that actually matter in a backend codebase, then gives you a decision framework.

The Contenders in One Line Each

Client	Request definition style	Best for
OkHttp	Hand-written `Request.Builder` code	Low-level control, streaming, custom protocols, performance-critical paths
RestTemplate	Hand-written URIs + `HttpEntity`/`HttpHeaders`	Classic Spring MVC codebases (deprecated in spirit by Spring in favor of WebClient)
OpenFeign	Annotated Java interfaces (`@GetMapping`, etc.)	Spring Cloud microservices with server-side (or declarative) contracts
JQuickCurl	Raw curl strings parsed by ANTLR4, plus variables & XML	Teams that live in Postman/browser curl and want zero hand-written request construction

What the Code Looks Like Side by Side

OkHttp — everything explicit, everything manual:

HttpUrl url = HttpUrl.get("https://jsonplaceholder.typicode.com/posts")
        .newBuilder()
        .addQueryParameter("userId", "1")
        .build();

RequestBody body = RequestBody.create(
        "{\"title\":\"ok\",\"body\":\"bar\",\"userId\":1}",
        MediaType.get("application/json; charset=utf-8"));

Request request = new Request.Builder()
        .url(url)
        .addHeader("Accept", "application/json")
        .post(body)
        .build();

try (Response response = new OkHttpClient().newCall(request).execute()) {
    System.out.println(response.body() != null ? response.body().string() : "");
}

RestTemplate — annotations gone, strings everywhere:

RestTemplate rest = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<String> entity = new HttpEntity<>("{\"title\":\"ok\",\"userId\":1}", headers);

ResponseEntity<Map> resp = rest.exchange(
        "https://jsonplaceholder.typicode.com/posts?userId={id}",
        HttpMethod.POST, entity, Map.class, 1);
System.out.println(resp.getBody());

OpenFeign — contract-driven, but only if the contract exists:

@FeignClient(name = "posts", url = "https://jsonplaceholder.typicode.com")
public interface PostClient {
    @PostMapping(value = "/posts", consumes = "application/json")
    Map<String, Object> create(@RequestBody Map<String, Object> payload);
}

JQuickCurl — the tested curl snippet is the code:

public interface PostApi {
    @JCurlCommand("curl -X POST https://jsonplaceholder.typicode.com/posts "
            + "-H 'Content-Type: application/json' "
            + "-d '{\"title\":\"ok\",\"body\":\"bar\",\"userId\":1}'")
    String create(JQuickCurlReq request);
}

The differences become obvious: OkHttp/RestTemplate force you to re-describe the request in builder API; OpenFeign introduces a parallel annotation vocabulary; JQuickCurl reuses the universal curl vocabulary you already test with.

Comparison Table: What Actually Differs

Criterion	OkHttp	RestTemplate	OpenFeign	JQuickCurl
Reuse Postman/browser curl	Manual rewrite	Manual rewrite	Manual rewrite	Paste directly
Dynamic requests (headers/body per call)	Code branches	Code branches	SpEL / interceptors	Variables `${...}` + XML `<if>`
Cross-team sharing of request format	None	None	Contract stubs	Same curl string
Proxy / dynamic invocation	N/A	N/A	Yes	Yes (`createProxy`)
Timeouts/retry/pool out of the box	Builder	Some	Via config	Global `JQuickCurlConfig`
Multipart upload / download	Manual	Manual	Manual	`-F` / `--output` in curl
Spring Cloud integration	No	Native template	Native	Bean wiring (manual, simple)
Dependency weight	Small	Spring Web	Spring Cloud stack	OkHttp + ANTLR runtime
Learning curve for new devs	Medium	Low	Low–Medium	Low if they know curl

When to Pick JQuickCurl (Honest Scenarios)

Choose JQuickCurl when:

You or your QA team already maintain curl collections in Postman and want them as executable Java code.
Third-party OpenAPI docs ship curl samples and you must integrate many endpoints quickly (see Post 18).
You need dynamic requests that depend on runtime state (auth tokens, environment hosts, feature flags) without writing factory methods per endpoint.
You want API definitions externalized in XML, decoupled from business code.

Still choose the alternatives when:

You are deep inside the Spring Cloud ecosystem and already own Feign clients — the load-balancer/service-discovery integration is a solved problem there.
You need WebFlux/reactive non-blocking I/O — JQuickCurl's model is synchronous OkHttp calls (though OkHttp itself is async-capable under the hood).
You only have a handful of endpoints and the team knows one client cold — introducing any new abstraction has a cost.

Decision Checklist

Do your requests already exist as curl commands? → strong signal for JQuickCurl.
Do you run a microservice mesh with Feign today? → stay on Feign unless curl reuse is a bigger pain.
Do you need reactive streaming? → OkHttp/WebClient territory.
Do you want one tool for the whole team to read requests? → JQuickCurl wins on readability.

Summary

None of these tools is universally "best". OkHttp is the raw engine, RestTemplate the legacy workhorse, OpenFeign the Spring-Cloud native, and JQuickCurl the only one that treats curl as a first-class, shareable request language. JQuickCurl is not a replacement for a full service-discovery stack — it's an alternative to hand-writing request builders, and in curl-heavy, integration-heavy codebases it removes a surprising amount of boilerplate. Source: dromara/jquick-curl.

In Post 4 we'll do something every backend dev needs: reuse curl snippets exported straight from Postman and the browser, without translating them by hand.

java #springboot #httpclient #opensource #java-library

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