diff --git a/registry/registry/repo.go b/registry/registry/repo.go
index 4395b21..bafac99 100644
--- a/registry/registry/repo.go
+++ b/registry/registry/repo.go
@@ -21,6 +21,7 @@ import (
 var ErrNotFound = errors.New("not found")
 var ErrUnknownComp = errors.New("unknown value for compatibility_mode")
 var ErrUnknownVal = errors.New("unknown value for validity mode")
+var ErrUnknownFormat = errors.New("unknown value for schema format")
 var ErrNotValid = errors.New("schema is not valid")
 var ErrNotComp = errors.New("schemas are not compatible")
 var ErrInvalidValueHeader = errors.New("invalid header value")
diff --git a/registry/server/handler.go b/registry/server/handler.go
index 7b484fa..3722663 100644
--- a/registry/server/handler.go
+++ b/registry/server/handler.go
@@ -159,9 +159,8 @@ func (h Handler) GetSpecificationByIdAndVersion(w http.ResponseWriter, r *http.R
 		log.Println(err)
 	}
 
-	body, _ := json.Marshal(specification)
 	writeResponse(w, responseBodyAndCode{
-		Body: body,
+		Body: specification,
 		Code: http.StatusOK,
 	})
 }
@@ -359,8 +358,8 @@ func (h Handler) GetSchemas(w http.ResponseWriter, _ *http.Request) {
 	if err != nil {
 		if errors.Is(err, registry.ErrNotFound) {
 			writeResponse(w, responseBodyAndCode{
-				Body: serializeErrorMessage(http.StatusText(http.StatusNotFound)),
-				Code: http.StatusNotFound,
+				Body: serializeErrorMessage("No active schemas registered in the Registry"),
+				Code: http.StatusNoContent,
 			})
 			return
 		}
@@ -535,8 +534,19 @@ func (h Handler) SearchSchemas(w http.ResponseWriter, r *http.Request) {
 // @Failure      500
 // @Router       /schemas [post]
 func (h Handler) PostSchema(w http.ResponseWriter, r *http.Request) {
+
 	registerRequest, err := readSchemaRegisterRequest(r.Body)
 	if err != nil {
+		if errors.Is(err, registry.ErrUnknownFormat) {
+			body, _ := json.Marshal(report{
+				Message: "Bad request: unknown format value",
+			})
+			writeResponse(w, responseBodyAndCode{
+				Body: body,
+				Code: http.StatusBadRequest,
+			})
+			return
+		}
 		writeResponse(w, responseBodyAndCode{
 			Body: serializeErrorMessage(http.StatusText(http.StatusBadRequest)),
 			Code: http.StatusBadRequest,
@@ -548,7 +558,7 @@ func (h Handler) PostSchema(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		if errors.Is(err, registry.ErrUnknownComp) {
 			body, _ := json.Marshal(report{
-				Message: "Bad request: unknown value for compatibility_mode",
+				Message: "Bad request: unknown compatibility_mode value",
 			})
 			writeResponse(w, responseBodyAndCode{
 				Body: body,
@@ -559,7 +569,7 @@ func (h Handler) PostSchema(w http.ResponseWriter, r *http.Request) {
 
 		if errors.Is(err, registry.ErrUnknownVal) {
 			body, _ := json.Marshal(report{
-				Message: "Bad request: unknown value for validity_mode",
+				Message: "Bad request: unknown validity_mode value",
 			})
 			writeResponse(w, responseBodyAndCode{
 				Body: body,
diff --git a/registry/server/util.go b/registry/server/util.go
index 3c52d5a..d596a3f 100644
--- a/registry/server/util.go
+++ b/registry/server/util.go
@@ -18,6 +18,7 @@ import (
 	"encoding/json"
 	"io"
 	"net/http"
+	"strings"
 
 	"github.com/dataphos/schema-registry/registry"
 )
@@ -27,6 +28,8 @@ type responseBodyAndCode struct {
 	Code int
 }
 
+var supportedFormats = []string{"json", "avro", "xml", "csv", "protobuf"}
+
 func writeResponse(w http.ResponseWriter, response responseBodyAndCode) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(response.Code)
@@ -49,9 +52,24 @@ func readSchemaRegisterRequest(body io.ReadCloser) (registry.SchemaRegistrationR
 		return registry.SchemaRegistrationRequest{}, err
 	}
 
+	// check if format is unknown
+	format := strings.ToLower(schemaRegisterRequest.SchemaType)
+	if !containsFormat(format) {
+		return registry.SchemaRegistrationRequest{}, registry.ErrUnknownFormat
+	}
+
 	return schemaRegisterRequest, nil
 }
 
+func containsFormat(format string) bool {
+	for _, supportedFormat := range supportedFormats {
+		if format == supportedFormat {
+			return true
+		}
+	}
+	return false
+}
+
 func readSchemaUpdateRequest(body io.ReadCloser) (registry.SchemaUpdateRequest, error) {
 	encoded, err := io.ReadAll(body)
 	if err != nil {
diff --git a/registry/validity/external/validity-checker/src/main/java/net/syntio/validity/checker/Checker.java b/registry/validity/external/validity-checker/src/main/java/net/syntio/validity/checker/Checker.java
index 74a9e5b..46ad3e3 100644
--- a/registry/validity/external/validity-checker/src/main/java/net/syntio/validity/checker/Checker.java
+++ b/registry/validity/external/validity-checker/src/main/java/net/syntio/validity/checker/Checker.java
@@ -32,7 +32,7 @@ public static boolean checkValidity(String schemaType, String schema, String mod
             case "full" -> ValidityLevel.FULL;
             default -> ValidityLevel.NONE;
         };
-        ContentValidator validator = ValidatorFactory.createValidator(schemaType);
+        ContentValidator validator = ValidatorFactory.createValidator(schemaType.toLowerCase());
         if (validator == null) { // in case ValidatorFactory returns null
           return false;
         }
diff --git a/registry/validity/http/http.go b/registry/validity/http/http.go
index 32b9c83..b130163 100644
--- a/registry/validity/http/http.go
+++ b/registry/validity/http/http.go
@@ -77,7 +77,7 @@ func CheckOverHTTP(ctx context.Context, schemaType, schema, mode, url string) (b
 
 	var parsedBody checkResponse
 	if err = json.Unmarshal(body, &parsedBody); err != nil {
-		return false, "error unmarshalling compatibility check body", err
+		return false, "error unmarshalling validity check body", err
 	}
 
 	valid := parsedBody.Result