diff --git a/belgif-rest-problem-it/belgif-rest-problem-it-common/src/main/java/io/github/belgif/rest/problem/it/AbstractRestProblemSpringBootIT.java b/belgif-rest-problem-it/belgif-rest-problem-it-common/src/main/java/io/github/belgif/rest/problem/it/AbstractRestProblemSpringBootIT.java
index 1c424bad..7b85e05b 100644
--- a/belgif-rest-problem-it/belgif-rest-problem-it-common/src/main/java/io/github/belgif/rest/problem/it/AbstractRestProblemSpringBootIT.java
+++ b/belgif-rest-problem-it/belgif-rest-problem-it-common/src/main/java/io/github/belgif/rest/problem/it/AbstractRestProblemSpringBootIT.java
@@ -72,7 +72,7 @@ public void notFound() {
         getSpec().when().get("/not/found").then().assertThat()
                 .statusCode(404)
                 .body("type", equalTo("urn:problem-type:belgif:resourceNotFound"))
-                .body("detail", equalTo("No resource /frontend/not/found found"));
+                .body("detail", stringContainsInOrder("No resource", "/not/found"));
     }
 
 }
diff --git a/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/main/java/io/github/belgif/rest/problem/ControllerHttpInterface.java b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/main/java/io/github/belgif/rest/problem/ControllerHttpInterface.java
new file mode 100644
index 00000000..6564e904
--- /dev/null
+++ b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/main/java/io/github/belgif/rest/problem/ControllerHttpInterface.java
@@ -0,0 +1,24 @@
+package io.github.belgif.rest.problem;
+
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Positive;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.service.annotation.GetExchange;
+
+@Validated
+@Controller
+public interface ControllerHttpInterface {
+
+    @GetExchange("/beanValidation/pathParameter/inherited/{param}")
+    ResponseEntity<String> beanValidationPathParameterInherited(
+            @PathVariable("param") @Positive @NotNull Integer p);
+
+    @GetExchange("/beanValidation/pathParameter/overridden/{param}")
+    ResponseEntity<String> beanValidationPathParameterOverridden(
+            @PathVariable("param") @Positive @NotNull Integer p);
+
+}
diff --git a/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/main/java/io/github/belgif/rest/problem/FrontendHttpController.java b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/main/java/io/github/belgif/rest/problem/FrontendHttpController.java
new file mode 100644
index 00000000..04ec065a
--- /dev/null
+++ b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/main/java/io/github/belgif/rest/problem/FrontendHttpController.java
@@ -0,0 +1,280 @@
+package io.github.belgif.rest.problem;
+
+import java.net.URI;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Positive;
+import jakarta.validation.constraints.Size;
+
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.boot.web.servlet.context.ServletWebServerInitializedEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestHeader;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.client.RestClient;
+import org.springframework.web.client.RestTemplate;
+import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.service.annotation.GetExchange;
+import org.springframework.web.service.annotation.HttpExchange;
+import org.springframework.web.service.annotation.PostExchange;
+
+import com.acme.custom.CustomProblem;
+
+import io.github.belgif.rest.problem.api.Input;
+import io.github.belgif.rest.problem.api.Problem;
+import io.github.belgif.rest.problem.i18n.I18N;
+import io.github.belgif.rest.problem.it.model.ChildModel;
+import io.github.belgif.rest.problem.it.model.JacksonModel;
+import io.github.belgif.rest.problem.it.model.Model;
+import io.github.belgif.rest.problem.it.model.NestedModel;
+import io.github.belgif.rest.problem.validation.RequestValidator;
+
+@RestController
+@HttpExchange("/frontend-http")
+@Validated
+public class FrontendHttpController implements ControllerHttpInterface {
+
+    private static final String DETAIL_MESSAGE_SUFFIX = " (caught successfully by frontend)";
+    private static final String ILLEGAL_STATE_MESSAGE_PREFIX = "Unsupported client ";
+
+    private final RestTemplateBuilder restTemplateBuilder;
+
+    private final WebClient.Builder webClientBuilder;
+
+    private final RestClient.Builder restClientBuilder;
+
+    private RestTemplate restTemplate;
+
+    private WebClient webClient;
+
+    private RestClient restClient;
+
+    public FrontendHttpController(RestTemplateBuilder restTemplateBuilder,
+            WebClient.Builder webClientBuilder,
+            RestClient.Builder restClientBuilder) {
+        this.restTemplateBuilder = restTemplateBuilder;
+        this.webClientBuilder = webClientBuilder;
+        this.restClientBuilder = restClientBuilder;
+    }
+
+    @EventListener
+    public void onApplicationEvent(ServletWebServerInitializedEvent event) {
+        this.restTemplate = restTemplateBuilder
+                .rootUri("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
+                .build();
+        this.webClient = webClientBuilder
+                .baseUrl("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
+                .build();
+        this.restClient = restClientBuilder
+                .baseUrl("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
+                .build();
+    }
+
+    @GetExchange("/ping")
+    public String ping() {
+        return "pong";
+    }
+
+    @GetExchange("/badRequest")
+    public void badRequest() {
+        BadRequestProblem problem = new BadRequestProblem();
+        problem.setDetail("Bad Request from frontend");
+        throw problem;
+    }
+
+    @GetExchange("/custom")
+    public void custom() {
+        throw new CustomProblem("value from frontend");
+    }
+
+    @GetExchange("/runtime")
+    public void runtime() {
+        throw new RuntimeException("oops");
+    }
+
+    @GetExchange("/unmapped")
+    public void unmapped() {
+        Problem unmapped = new Problem(URI.create("urn:problem-type:belgif:test:unmapped"), "Unmapped problem", 400) {
+        };
+        unmapped.setDetail("Unmapped problem from frontend");
+        throw unmapped;
+    }
+
+    @GetExchange("/retryAfter")
+    public void retryAfter() {
+        ServiceUnavailableProblem problem = new ServiceUnavailableProblem();
+        problem.setRetryAfterSec(10000L);
+        throw problem;
+    }
+
+    @GetExchange(value = "/okFromBackend", accept = "application/json")
+    public ResponseEntity<String> okFromBackend(@RequestParam("client") Client client) {
+        String result = null;
+        if (client == Client.REST_TEMPLATE) {
+            result = restTemplate.getForObject("/ok", String.class);
+        } else if (client == Client.WEB_CLIENT) {
+            result = webClient.get().uri("/ok").retrieve().toEntity(String.class).block().getBody();
+        } else if (client == Client.REST_CLIENT) {
+            result = restClient.get().uri("/ok").retrieve().toEntity(String.class).getBody();
+        }
+        return ResponseEntity.ok(result);
+    }
+
+    @GetExchange("/badRequestFromBackend")
+    public void badRequestFromBackend(@RequestParam("client") Client client) {
+        try {
+            if (client == Client.REST_TEMPLATE) {
+                restTemplate.getForObject("/badRequest", String.class);
+            } else if (client == Client.WEB_CLIENT) {
+                webClient.get().uri("/badRequest").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/badRequest").retrieve().toEntity(String.class);
+            }
+            throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+        } catch (BadRequestProblem e) {
+            e.setDetail(e.getDetail() + DETAIL_MESSAGE_SUFFIX);
+            throw e;
+        }
+    }
+
+    @GetExchange("/customFromBackend")
+    public void customFromBackend(@RequestParam("client") Client client) {
+        try {
+            if (client == Client.REST_TEMPLATE) {
+                restTemplate.getForObject("/custom", String.class);
+            } else if (client == Client.WEB_CLIENT) {
+                webClient.get().uri("/custom").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/custom").retrieve().toEntity(String.class);
+            }
+            throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+        } catch (CustomProblem e) {
+            e.setCustomField(e.getCustomField() + DETAIL_MESSAGE_SUFFIX);
+            throw e;
+        }
+    }
+
+    @GetExchange("/unmappedFromBackend")
+    public void unmappedFromBackend(@RequestParam("client") Client client) {
+        try {
+            if (client == Client.REST_TEMPLATE) {
+                restTemplate.getForObject("/unmapped", String.class);
+            } else if (client == Client.WEB_CLIENT) {
+                webClient.get().uri("/unmapped").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/unmapped").retrieve().toEntity(String.class);
+            }
+            throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+        } catch (DefaultProblem e) {
+            e.setDetail(e.getDetail() + DETAIL_MESSAGE_SUFFIX);
+            throw e;
+        }
+    }
+
+    @GetExchange("/applicationJsonProblemFromBackend")
+    public void applicationJsonProblemFromBackend(@RequestParam("client") Client client) {
+        try {
+            if (client == Client.REST_TEMPLATE) {
+                restTemplate.getForObject("/applicationJsonProblem", String.class);
+            } else if (client == Client.WEB_CLIENT) {
+                webClient.get().uri("/applicationJsonProblem").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/applicationJsonProblem").retrieve().toEntity(String.class);
+            }
+            throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+        } catch (BadRequestProblem e) {
+            e.setDetail(e.getDetail() + DETAIL_MESSAGE_SUFFIX);
+            throw e;
+        }
+    }
+
+    @GetExchange("/jacksonMismatchedInputFromBackend")
+    public void jacksonMismatchedInputFromBackend(@RequestParam("client") Client client) {
+        if (client == Client.REST_TEMPLATE) {
+            restTemplate.getForObject("/jacksonMismatchedInput", JacksonModel.class);
+        } else if (client == Client.WEB_CLIENT) {
+            webClient.get().uri("/jacksonMismatchedInput").retrieve().toEntity(JacksonModel.class).block();
+        } else if (client == Client.REST_CLIENT) {
+            restClient.get().uri("/jacksonMismatchedInput").retrieve().toEntity(JacksonModel.class);
+        }
+        throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+    }
+
+    @GetExchange("/beanValidation/queryParameter")
+    public ResponseEntity<String> beanValidationQueryParameter(
+            @RequestParam("param") @Positive @NotNull Integer p,
+            @RequestParam @Size(max = 5) String other) {
+        return ResponseEntity.ok("param: " + p + ", other: " + other);
+    }
+
+    @GetExchange("/beanValidation/headerParameter")
+    public ResponseEntity<String> beanValidationHeaderParameter(
+            @RequestHeader("param") @Positive @NotNull Integer p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @GetExchange("/beanValidation/pathParameter/class/{param}")
+    public ResponseEntity<String> beanValidationPathParameter(
+            @PathVariable("param") @Positive @NotNull Integer p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @Override
+    public ResponseEntity<String> beanValidationPathParameterInherited(Integer p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @Override
+    @GetExchange("/beanValidation/pathParameter/overridden")
+    public ResponseEntity<String> beanValidationPathParameterOverridden(@RequestParam("param") Integer p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @PostExchange("/beanValidation/body")
+    public ResponseEntity<String> beanValidationBody(@Valid @RequestBody Model body) {
+        return ResponseEntity.ok("body: " + body);
+    }
+
+    @PostExchange("/beanValidation/body/nested")
+    public ResponseEntity<String> beanValidationBodyNested(@Valid @RequestBody NestedModel body) {
+        return ResponseEntity.ok("body: " + body);
+    }
+
+    @PostExchange("/beanValidation/body/inheritance")
+    public ResponseEntity<String> beanValidationBodyInheritance(@Valid @RequestBody ChildModel body) {
+        return ResponseEntity.ok("body: " + body);
+    }
+
+    @PostExchange("/beanValidation/queryParameter/nested")
+    public ResponseEntity<String> beanValidationQueryParameterNested(@Valid Model p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @PostExchange("/jackson/mismatchedInputException")
+    public ResponseEntity<String> jacksonMismatchedInputException(@Valid @RequestBody JacksonModel p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @PostExchange("/i18n")
+    public ResponseEntity<Void> i18n(@RequestParam("enabled") boolean enabled) {
+        I18N.setEnabled(enabled);
+        return ResponseEntity.ok().build();
+    }
+
+    @GetExchange("/requestValidator")
+    public ResponseEntity<Void> requestValidator(@RequestParam("ssin") String ssin,
+            @RequestParam(name = "a", required = false) String a,
+            @RequestParam(name = "b", required = false) String b) {
+        new RequestValidator().ssin(Input.query("ssin", ssin))
+                .zeroOrAllOf(Input.query("a", a), Input.query("b", b))
+                .validate();
+        return ResponseEntity.ok().build();
+    }
+
+}
diff --git a/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/test/java/io/github/belgif/rest/problem/RestProblemSpringBoot3HttpExchangeIT.java b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/test/java/io/github/belgif/rest/problem/RestProblemSpringBoot3HttpExchangeIT.java
new file mode 100644
index 00000000..fb944708
--- /dev/null
+++ b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/test/java/io/github/belgif/rest/problem/RestProblemSpringBoot3HttpExchangeIT.java
@@ -0,0 +1,31 @@
+package io.github.belgif.rest.problem;
+
+import java.util.Arrays;
+import java.util.stream.Stream;
+
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.server.LocalServerPort;
+import org.springframework.test.annotation.DirtiesContext;
+
+import io.github.belgif.rest.problem.it.AbstractRestProblemSpringBootIT;
+import io.restassured.RestAssured;
+import io.restassured.specification.RequestSpecification;
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+@DirtiesContext
+class RestProblemSpringBoot3HttpExchangeIT extends AbstractRestProblemSpringBootIT {
+
+    @LocalServerPort
+    private int port;
+
+    @Override
+    protected RequestSpecification getSpec() {
+        return RestAssured.with().baseUri("http://localhost").port(port).basePath("/spring/frontend-http");
+    }
+
+    @Override
+    protected Stream<String> getClients() {
+        return Arrays.stream(Client.values()).map(Client::name);
+    }
+
+}
diff --git a/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/main/java/io/github/belgif/rest/problem/ControllerHttpInterface.java b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/main/java/io/github/belgif/rest/problem/ControllerHttpInterface.java
new file mode 100644
index 00000000..6564e904
--- /dev/null
+++ b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/main/java/io/github/belgif/rest/problem/ControllerHttpInterface.java
@@ -0,0 +1,24 @@
+package io.github.belgif.rest.problem;
+
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Positive;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.service.annotation.GetExchange;
+
+@Validated
+@Controller
+public interface ControllerHttpInterface {
+
+    @GetExchange("/beanValidation/pathParameter/inherited/{param}")
+    ResponseEntity<String> beanValidationPathParameterInherited(
+            @PathVariable("param") @Positive @NotNull Integer p);
+
+    @GetExchange("/beanValidation/pathParameter/overridden/{param}")
+    ResponseEntity<String> beanValidationPathParameterOverridden(
+            @PathVariable("param") @Positive @NotNull Integer p);
+
+}
diff --git a/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/main/java/io/github/belgif/rest/problem/FrontendHttpController.java b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/main/java/io/github/belgif/rest/problem/FrontendHttpController.java
new file mode 100644
index 00000000..9236bb8b
--- /dev/null
+++ b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/main/java/io/github/belgif/rest/problem/FrontendHttpController.java
@@ -0,0 +1,280 @@
+package io.github.belgif.rest.problem;
+
+import java.net.URI;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Positive;
+import jakarta.validation.constraints.Size;
+
+import org.springframework.boot.restclient.RestTemplateBuilder;
+import org.springframework.boot.web.server.servlet.context.ServletWebServerInitializedEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestHeader;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.client.RestClient;
+import org.springframework.web.client.RestTemplate;
+import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.service.annotation.GetExchange;
+import org.springframework.web.service.annotation.HttpExchange;
+import org.springframework.web.service.annotation.PostExchange;
+
+import com.acme.custom.CustomProblem;
+
+import io.github.belgif.rest.problem.api.Input;
+import io.github.belgif.rest.problem.api.Problem;
+import io.github.belgif.rest.problem.i18n.I18N;
+import io.github.belgif.rest.problem.it.model.ChildModel;
+import io.github.belgif.rest.problem.it.model.JacksonModel;
+import io.github.belgif.rest.problem.it.model.Model;
+import io.github.belgif.rest.problem.it.model.NestedModel;
+import io.github.belgif.rest.problem.validation.RequestValidator;
+
+@RestController
+@HttpExchange("/frontend-http")
+@Validated
+public class FrontendHttpController implements ControllerHttpInterface {
+
+    private static final String DETAIL_MESSAGE_SUFFIX = " (caught successfully by frontend)";
+    private static final String ILLEGAL_STATE_MESSAGE_PREFIX = "Unsupported client ";
+
+    private final RestTemplateBuilder restTemplateBuilder;
+
+    private final WebClient.Builder webClientBuilder;
+
+    private final RestClient.Builder restClientBuilder;
+
+    private RestTemplate restTemplate;
+
+    private WebClient webClient;
+
+    private RestClient restClient;
+
+    public FrontendHttpController(RestTemplateBuilder restTemplateBuilder,
+            WebClient.Builder webClientBuilder,
+            RestClient.Builder restClientBuilder) {
+        this.restTemplateBuilder = restTemplateBuilder;
+        this.webClientBuilder = webClientBuilder;
+        this.restClientBuilder = restClientBuilder;
+    }
+
+    @EventListener
+    public void onApplicationEvent(ServletWebServerInitializedEvent event) {
+        this.restTemplate = restTemplateBuilder
+                .rootUri("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
+                .build();
+        this.webClient = webClientBuilder
+                .baseUrl("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
+                .build();
+        this.restClient = restClientBuilder
+                .baseUrl("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
+                .build();
+    }
+
+    @GetExchange("/ping")
+    public String ping() {
+        return "pong";
+    }
+
+    @GetExchange("/badRequest")
+    public void badRequest() {
+        BadRequestProblem problem = new BadRequestProblem();
+        problem.setDetail("Bad Request from frontend");
+        throw problem;
+    }
+
+    @GetExchange("/custom")
+    public void custom() {
+        throw new CustomProblem("value from frontend");
+    }
+
+    @GetExchange("/runtime")
+    public void runtime() {
+        throw new RuntimeException("oops");
+    }
+
+    @GetExchange("/unmapped")
+    public void unmapped() {
+        Problem unmapped = new Problem(URI.create("urn:problem-type:belgif:test:unmapped"), "Unmapped problem", 400) {
+        };
+        unmapped.setDetail("Unmapped problem from frontend");
+        throw unmapped;
+    }
+
+    @GetExchange("/retryAfter")
+    public void retryAfter() {
+        ServiceUnavailableProblem problem = new ServiceUnavailableProblem();
+        problem.setRetryAfterSec(10000L);
+        throw problem;
+    }
+
+    @GetExchange(value = "/okFromBackend", accept = "application/json")
+    public ResponseEntity<String> okFromBackend(@RequestParam("client") Client client) {
+        String result = null;
+        if (client == Client.REST_TEMPLATE) {
+            result = restTemplate.getForObject("/ok", String.class);
+        } else if (client == Client.WEB_CLIENT) {
+            result = webClient.get().uri("/ok").retrieve().toEntity(String.class).block().getBody();
+        } else if (client == Client.REST_CLIENT) {
+            result = restClient.get().uri("/ok").retrieve().toEntity(String.class).getBody();
+        }
+        return ResponseEntity.ok(result);
+    }
+
+    @GetExchange("/badRequestFromBackend")
+    public void badRequestFromBackend(@RequestParam("client") Client client) {
+        try {
+            if (client == Client.REST_TEMPLATE) {
+                restTemplate.getForObject("/badRequest", String.class);
+            } else if (client == Client.WEB_CLIENT) {
+                webClient.get().uri("/badRequest").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/badRequest").retrieve().toEntity(String.class);
+            }
+            throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+        } catch (BadRequestProblem e) {
+            e.setDetail(e.getDetail() + DETAIL_MESSAGE_SUFFIX);
+            throw e;
+        }
+    }
+
+    @GetExchange("/customFromBackend")
+    public void customFromBackend(@RequestParam("client") Client client) {
+        try {
+            if (client == Client.REST_TEMPLATE) {
+                restTemplate.getForObject("/custom", String.class);
+            } else if (client == Client.WEB_CLIENT) {
+                webClient.get().uri("/custom").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/custom").retrieve().toEntity(String.class);
+            }
+            throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+        } catch (CustomProblem e) {
+            e.setCustomField(e.getCustomField() + DETAIL_MESSAGE_SUFFIX);
+            throw e;
+        }
+    }
+
+    @GetExchange("/unmappedFromBackend")
+    public void unmappedFromBackend(@RequestParam("client") Client client) {
+        try {
+            if (client == Client.REST_TEMPLATE) {
+                restTemplate.getForObject("/unmapped", String.class);
+            } else if (client == Client.WEB_CLIENT) {
+                webClient.get().uri("/unmapped").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/unmapped").retrieve().toEntity(String.class);
+            }
+            throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+        } catch (DefaultProblem e) {
+            e.setDetail(e.getDetail() + DETAIL_MESSAGE_SUFFIX);
+            throw e;
+        }
+    }
+
+    @GetExchange("/applicationJsonProblemFromBackend")
+    public void applicationJsonProblemFromBackend(@RequestParam("client") Client client) {
+        try {
+            if (client == Client.REST_TEMPLATE) {
+                restTemplate.getForObject("/applicationJsonProblem", String.class);
+            } else if (client == Client.WEB_CLIENT) {
+                webClient.get().uri("/applicationJsonProblem").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/applicationJsonProblem").retrieve().toEntity(String.class);
+            }
+            throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+        } catch (BadRequestProblem e) {
+            e.setDetail(e.getDetail() + DETAIL_MESSAGE_SUFFIX);
+            throw e;
+        }
+    }
+
+    @GetExchange("/jacksonMismatchedInputFromBackend")
+    public void jacksonMismatchedInputFromBackend(@RequestParam("client") Client client) {
+        if (client == Client.REST_TEMPLATE) {
+            restTemplate.getForObject("/jacksonMismatchedInput", JacksonModel.class);
+        } else if (client == Client.WEB_CLIENT) {
+            webClient.get().uri("/jacksonMismatchedInput").retrieve().toEntity(JacksonModel.class).block();
+        } else if (client == Client.REST_CLIENT) {
+            restClient.get().uri("/jacksonMismatchedInput").retrieve().toEntity(JacksonModel.class);
+        }
+        throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
+    }
+
+    @GetExchange("/beanValidation/queryParameter")
+    public ResponseEntity<String> beanValidationQueryParameter(
+            @RequestParam("param") @Positive @NotNull Integer p,
+            @RequestParam @Size(max = 5) String other) {
+        return ResponseEntity.ok("param: " + p + ", other: " + other);
+    }
+
+    @GetExchange("/beanValidation/headerParameter")
+    public ResponseEntity<String> beanValidationHeaderParameter(
+            @RequestHeader("param") @Positive @NotNull Integer p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @GetExchange("/beanValidation/pathParameter/class/{param}")
+    public ResponseEntity<String> beanValidationPathParameter(
+            @PathVariable("param") @Positive @NotNull Integer p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @Override
+    public ResponseEntity<String> beanValidationPathParameterInherited(Integer p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @Override
+    @GetExchange("/beanValidation/pathParameter/overridden")
+    public ResponseEntity<String> beanValidationPathParameterOverridden(@RequestParam("param") Integer p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @PostExchange("/beanValidation/body")
+    public ResponseEntity<String> beanValidationBody(@Valid @RequestBody Model body) {
+        return ResponseEntity.ok("body: " + body);
+    }
+
+    @PostExchange("/beanValidation/body/nested")
+    public ResponseEntity<String> beanValidationBodyNested(@Valid @RequestBody NestedModel body) {
+        return ResponseEntity.ok("body: " + body);
+    }
+
+    @PostExchange("/beanValidation/body/inheritance")
+    public ResponseEntity<String> beanValidationBodyInheritance(@Valid @RequestBody ChildModel body) {
+        return ResponseEntity.ok("body: " + body);
+    }
+
+    @PostExchange("/beanValidation/queryParameter/nested")
+    public ResponseEntity<String> beanValidationQueryParameterNested(@Valid Model p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @PostExchange("/jackson/mismatchedInputException")
+    public ResponseEntity<String> jacksonMismatchedInputException(@Valid @RequestBody JacksonModel p) {
+        return ResponseEntity.ok("param: " + p);
+    }
+
+    @PostExchange("/i18n")
+    public ResponseEntity<Void> i18n(@RequestParam("enabled") boolean enabled) {
+        I18N.setEnabled(enabled);
+        return ResponseEntity.ok().build();
+    }
+
+    @GetExchange("/requestValidator")
+    public ResponseEntity<Void> requestValidator(@RequestParam("ssin") String ssin,
+            @RequestParam(name = "a", required = false) String a,
+            @RequestParam(name = "b", required = false) String b) {
+        new RequestValidator().ssin(Input.query("ssin", ssin))
+                .zeroOrAllOf(Input.query("a", a), Input.query("b", b))
+                .validate();
+        return ResponseEntity.ok().build();
+    }
+
+}
diff --git a/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/test/java/io/github/belgif/rest/problem/RestProblemSpringBoot4HttpExchangeIT.java b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/test/java/io/github/belgif/rest/problem/RestProblemSpringBoot4HttpExchangeIT.java
new file mode 100644
index 00000000..22b220e3
--- /dev/null
+++ b/belgif-rest-problem-it/belgif-rest-problem-spring-boot-4-it/src/test/java/io/github/belgif/rest/problem/RestProblemSpringBoot4HttpExchangeIT.java
@@ -0,0 +1,31 @@
+package io.github.belgif.rest.problem;
+
+import java.util.Arrays;
+import java.util.stream.Stream;
+
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.server.LocalServerPort;
+import org.springframework.test.annotation.DirtiesContext;
+
+import io.github.belgif.rest.problem.it.AbstractRestProblemSpringBootIT;
+import io.restassured.RestAssured;
+import io.restassured.specification.RequestSpecification;
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+@DirtiesContext
+class RestProblemSpringBoot4HttpExchangeIT extends AbstractRestProblemSpringBootIT {
+
+    @LocalServerPort
+    private int port;
+
+    @Override
+    protected RequestSpecification getSpec() {
+        return RestAssured.with().baseUri("http://localhost").port(port).basePath("/spring/frontend-http");
+    }
+
+    @Override
+    protected Stream<String> getClients() {
+        return Arrays.stream(Client.values()).map(Client::name);
+    }
+
+}