REST Assured is not the only way to make HTTP calls in Java. HttpClient, OkHttp, Retrofit — all of them can send requests and read responses. So why does the QA world overwhelmingly choose REST Assured? Let us compare.
| Library | Built By | Primary Use | QA Friendly? |
|---|---|---|---|
| REST Assured | Open source (Johan Haleby) | API test automation | Yes — designed for testing |
| Java HttpClient | Oracle (built into JDK 11+) | General HTTP communication | No — no built-in assertions |
| OkHttp | Square | Android apps, HTTP clients | No — designed for app development |
| Retrofit | Square | Type-safe REST clients | No — designed for app development |
| Apache HttpClient | Apache Foundation | Legacy HTTP communication | No — verbose, low-level |
// REST Assured — 8 lines, readable, assertions built-in
given()
.queryParam("userId", 1)
.when()
.get("/posts")
.then()
.statusCode(200)
.body("size()", equalTo(10))
.body("userId", everyItem(equalTo(1)));// Java HttpClient — 15+ lines, manual parsing, manual assertions
HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create("https://jsonplaceholder.typicode.com/posts?userId=1"))
.GET()
.build();
HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
assertEquals(200, response.statusCode());
// Now you need to parse JSON manually
ObjectMapper mapper = new ObjectMapper();
List<Map<String, Object>> posts = mapper.readValue(response.body(), List.class);
assertEquals(10, posts.size());
for (Map<String, Object> post : posts) {
assertEquals(1, post.get("userId"));
}If an interviewer asks "Can you use HttpClient for API testing?" — the answer is yes, technically. But REST Assured gives you assertions, logging, BDD syntax, and JSON parsing for free. Using HttpClient for testing is like driving a screw with a hammer — it works, but the screwdriver exists for a reason.
Q: Why do you prefer REST Assured over HttpClient or OkHttp for API testing?
A: REST Assured is purpose-built for API testing. It gives you BDD syntax (given/when/then), built-in Hamcrest matchers for assertions, automatic JSON parsing, request/response logging, and spec builders for reusability — all out of the box. With HttpClient or OkHttp, you get raw HTTP functionality but must manually parse JSON, write your own assertions, and build your own logging. REST Assured lets me write 8 lines of readable code where HttpClient needs 20+ lines. It also integrates natively with TestNG/JUnit. The QA industry standardized on REST Assured, so using it means your code is readable by any QA engineer who joins the team.
Key Point: REST Assured is purpose-built for testing — BDD syntax, built-in assertions, automatic JSON parsing. HttpClient/OkHttp are for building apps, not testing them. Use the right tool for the job.