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Technology

Rest Assured

Difficulty

Intermediate

Experience

1-2 Years

Type

Technical

AutomateQA Team

QA Automation Engineers

June 19, 2026

Interview Question

How do you validate query parameters in API testing?

Answer

Validating Query Parameters in API Testing

Query parameters are key-value pairs appended to a URL after ?, separated by & for multiple parameters.

Example URL:

CODE

https://api.example.com/products?category=electronics&price=500

Here category and price are query parameters.

Validation Checklist

1. Presence Check

Ensure mandatory parameters are present in the request.

Java

// Test missing required query param
given()
    .when()
    .get("/products")  // missing 'category'
    .then()
    .statusCode(400)
    .body("error", equalTo("category is required"));

2. Type Check

Ensure the parameter''s type matches expectations (e.g., price must be a number).

Java

given()
    .queryParam("price", "not-a-number")
    .when()
    .get("/products")
    .then()
    .statusCode(400);

3. Range or Format Check

Check if value fits within an acceptable range or format.

Java

given()
    .queryParam("price", -100)  // negative price
    .when()
    .get("/products")
    .then()
    .statusCode(400)
    .body("error", equalTo("Price must be a positive number"));

4. Special Characters and Edge Cases

Test with empty values, spaces, and special characters.

Java

given()
    .queryParam("category", "")
    .when()
    .get("/products")
    .then()
    .statusCode(400);

Important Note

If any parameter fails validation, the API should respond with a clear error message. For example, if price is negative: "Price must be a positive number."