diff --git a/src/mjson.c b/src/mjson.c
index 55ba507..36c151b 100644
--- a/src/mjson.c
+++ b/src/mjson.c
@@ -998,10 +998,20 @@ void jsonrpc_return_success(struct jsonrpc_request *r, const char *result_fmt,
 void jsonrpc_ctx_process(struct jsonrpc_ctx *ctx, const char *buf, int len,
                          mjson_print_fn_t fn, void *fn_data, void *ud) {
   const char *result = NULL, *error = NULL;
-  int result_sz = 0, error_sz = 0;
+  int result_sz = 0, error_sz = 0, id_tok = MJSON_TOK_INVALID, 
+    params_tok = MJSON_TOK_INVALID;
   struct jsonrpc_method *m = NULL;
   struct jsonrpc_request r = {ctx, buf, len, 0, 0, 0, 0, 0, 0, fn, fn_data, ud};
 
+  // Request must be a valid object
+  if (mjson_find(buf, len, "$", &r.method, &r.method_len) !=
+      MJSON_TOK_OBJECT) {
+    mjson_printf(fn, fn_data,
+                 "{\"error\":{\"code\":%d,\"message\":%Q},\"id\":null}\n",
+                 JSONRPC_ERROR_PARSE, JSONRPC_ERROR_MSG_PARSE);
+    return;
+  }
+
   // Is is a response frame?
   mjson_find(buf, len, "$.result", &result, &result_sz);
   if (result == NULL) mjson_find(buf, len, "$.error", &error, &error_sz);
@@ -1010,17 +1020,48 @@ void jsonrpc_ctx_process(struct jsonrpc_ctx *ctx, const char *buf, int len,
     return;
   }
 
+  // id is optional
+  id_tok = mjson_find(buf, len, "$.id", &r.id, &r.id_len);
+  // id (if exists) must be a number, string or null
+  if (id_tok != MJSON_TOK_INVALID && id_tok != MJSON_TOK_NUMBER &&
+      id_tok != MJSON_TOK_STRING && id_tok != MJSON_TOK_NULL) {
+    mjson_printf(fn, fn_data,
+                 "{\"error\":{\"code\":%d,\"message\":%Q},\"id\":null}\n",
+                 JSONRPC_ERROR_BAD_REQUEST, JSONRPC_ERROR_MSG_BAD_REQUEST);
+    return;
+  }
+
   // Method must exist and must be a string
   if (mjson_find(buf, len, "$.method", &r.method, &r.method_len) !=
       MJSON_TOK_STRING) {
-    mjson_printf(fn, fn_data,
-                 "{\"error\":{\"code\":-32700,\"message\":%.*Q}}\n", len, buf);
+    // use null as id if it is not present
+    if(id_tok == MJSON_TOK_INVALID){
+      mjson_printf(fn, fn_data,
+                   "{\"error\":{\"code\":%d,\"message\":%Q},\"id\":null}\n", 
+                   JSONRPC_ERROR_BAD_REQUEST, JSONRPC_ERROR_MSG_BAD_REQUEST);
+      return;
+    }
+    jsonrpc_return_error(&r, JSONRPC_ERROR_BAD_REQUEST, 
+                         JSONRPC_ERROR_MSG_BAD_REQUEST, NULL);
     return;
   }
 
-  // id and params are optional
-  mjson_find(buf, len, "$.id", &r.id, &r.id_len);
-  mjson_find(buf, len, "$.params", &r.params, &r.params_len);
+  // params are optional
+  params_tok = mjson_find(buf, len, "$.params", &r.params, &r.params_len);
+  // params (if exists) must be an object or an array
+  if (params_tok != MJSON_TOK_INVALID && params_tok != MJSON_TOK_OBJECT &&
+      params_tok != MJSON_TOK_ARRAY) {
+    // use null as id if it is not present
+    if(id_tok == MJSON_TOK_INVALID){
+      mjson_printf(fn, fn_data,
+                   "{\"error\":{\"code\":%d,\"message\":%Q},\"id\":null}\n", 
+                   JSONRPC_ERROR_BAD_REQUEST, JSONRPC_ERROR_MSG_BAD_REQUEST);
+      return;
+    }
+    jsonrpc_return_error(&r, JSONRPC_ERROR_BAD_REQUEST, 
+                         JSONRPC_ERROR_MSG_BAD_REQUEST, NULL);
+    return;
+  }
 
   for (m = ctx->methods; m != NULL; m = m->next) {
     if (mjson_globmatch(m->method, m->method_sz, r.method + 1,
@@ -1031,7 +1072,8 @@ void jsonrpc_ctx_process(struct jsonrpc_ctx *ctx, const char *buf, int len,
     }
   }
   if (m == NULL) {
-    jsonrpc_return_error(&r, JSONRPC_ERROR_NOT_FOUND, "method not found", NULL);
+    jsonrpc_return_error(&r, JSONRPC_ERROR_METHOD_NOT_FOUND, 
+                         JSONRPC_ERROR_MSG_METHOD_NOT_FOUND, NULL);
   }
 }
 
diff --git a/src/mjson.h b/src/mjson.h
index d8156e0..cb2c798 100644
--- a/src/mjson.h
+++ b/src/mjson.h
@@ -208,10 +208,17 @@ extern void jsonrpc_list(struct jsonrpc_request *r);
 #define jsonrpc_process(buf, len, fn, fnd, ud) \
   jsonrpc_ctx_process(&jsonrpc_default_context, (buf), (len), (fn), (fnd), (ud))
 
-#define JSONRPC_ERROR_INVALID -32700    /* Invalid JSON was received */
-#define JSONRPC_ERROR_NOT_FOUND -32601  /* The method does not exist */
-#define JSONRPC_ERROR_BAD_PARAMS -32602 /* Invalid params passed */
-#define JSONRPC_ERROR_INTERNAL -32603   /* Internal JSON-RPC error */
+#define JSONRPC_ERROR_PARSE -32700            /* Invalid JSON was received */
+#define JSONRPC_ERROR_BAD_REQUEST -32600      /* The JSON sent is not a valid Request object */
+#define JSONRPC_ERROR_METHOD_NOT_FOUND -32601 /* The method does not exist or is not available*/
+#define JSONRPC_ERROR_BAD_PARAMS -32602       /* Invalid method parameter(s) */
+#define JSONRPC_ERROR_INTERNAL -32603         /* Internal JSON-RPC error */
+
+#define JSONRPC_ERROR_MSG_PARSE "Parse error"
+#define JSONRPC_ERROR_MSG_BAD_REQUEST "Invalid Request"
+#define JSONRPC_ERROR_MSG_METHOD_NOT_FOUND "Method not found"
+#define JSONRPC_ERROR_MSG_BAD_PARAMS "Invalid params"
+#define JSONRPC_ERROR_MSG_INTERNAL "Internal error"
 
 #endif  // MJSON_ENABLE_RPC
 #ifdef __cplusplus
diff --git a/test/unit_test.c b/test/unit_test.c
index 6d5f5bd..10019fe 100644
--- a/test/unit_test.c
+++ b/test/unit_test.c
@@ -616,15 +616,26 @@ static void test_rpc(void) {
   res = "{\"id\":1,\"result\":[\"rpc.list\"]}\n";
   fb.len = 0;
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 
   // Call non-existent method
   req = "{\"id\": 1, \"method\": \"foo\"}\n";
   res =
-      "{\"id\":1,\"error\":{\"code\":-32601,\"message\":\"method not "
+      "{\"id\":1,\"error\":{\"code\":-32601,\"message\":\"Method not "
       "found\"}}\n";
   fb.len = 0;
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad method
+  req = "{\"id\": 1, \"method\": 123}\n";
+  res = "{\"id\":1,\"error\":{\"code\":-32600,\"message\":\"Invalid "
+        "Request\"}}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 
   // Register our own function
@@ -634,13 +645,97 @@ static void test_rpc(void) {
   jsonrpc_export("foo", foo);
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb,
                   (void *) "hi");
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 
   // Test for bad frame
   req = "boo\n";
-  res = "{\"error\":{\"code\":-32700,\"message\":\"boo\\n\"}}\n";
+  res = "{\"error\":{\"code\":-32700,\"message\":\"Parse error\"},"
+        "\"id\":null}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad request: id is array
+  req = "{\"id\": [2], \"method\": \"baz\"}\n";
+  res = "{\"error\":{\"code\":-32600,\"message\":\"Invalid Request\"},"
+        "\"id\":null}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad request: id is object
+  req = "{\"id\": {\"a\":2}, \"method\": \"baz\"}\n";
+  res = "{\"error\":{\"code\":-32600,\"message\":\"Invalid Request\"},"
+        "\"id\":null}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad request: id is boolean
+  req = "{\"id\":true, \"method\": \"baz\"}\n";
+  res = "{\"error\":{\"code\":-32600,\"message\":\"Invalid Request\"},"
+        "\"id\":null}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad request: params is number
+  req = "{\"id\": 1, \"method\": \"foo\", \"params\": 1}\n";
+  res = "{\"id\":1,\"error\":{\"code\":-32600,\"message\":\"Invalid "
+        "Request\"}}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad request: params is string
+  req = "{\"id\": 1, \"method\": \"foo\", \"params\": \"bar\"}\n";
+  res = "{\"id\":1,\"error\":{\"code\":-32600,\"message\":\"Invalid "
+        "Request\"}}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad request: params is boolean
+  req = "{\"id\": 1, \"method\": \"foo\", \"params\": true}\n";
+  res = "{\"id\":1,\"error\":{\"code\":-32600,\"message\":\"Invalid "
+        "Request\"}}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad notification: params is number
+  req = "{\"method\": \"foo\", \"params\": 1}\n";
+  res = "{\"error\":{\"code\":-32600,\"message\":\"Invalid Request\"},"
+        "\"id\":null}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad notification: params is string
+  req = "{\"method\": \"foo\", \"params\": \"bar\"}\n";
+  res = "{\"error\":{\"code\":-32600,\"message\":\"Invalid Request\"},"
+        "\"id\":null}\n";
+  fb.len = 0;
+  jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
+  ASSERT(strcmp(buf, res) == 0);
+
+  // Test for bad notification: params is boolean
+  req = "{\"method\": \"foo\", \"params\": true}\n";
+  res = "{\"error\":{\"code\":-32600,\"message\":\"Invalid Request\"},"
+        "\"id\":null}\n";
   fb.len = 0;
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 
   // Test simple error response, without data
@@ -649,6 +744,7 @@ static void test_rpc(void) {
   jsonrpc_export("foo1", foo1);
   fb.len = 0;
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 
   // Test more complex error response, with data
@@ -659,6 +755,7 @@ static void test_rpc(void) {
   jsonrpc_export("foo2", foo2);
   fb.len = 0;
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 
   // Test notify - must not generate a response
@@ -672,6 +769,7 @@ static void test_rpc(void) {
   res = ">>{\"id\":123,\"result\":[1,2,3]}<<";
   fb.len = 0;
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 
   // Test error response
@@ -679,6 +777,7 @@ static void test_rpc(void) {
   res = ">>{\"id\":566,\"error\":{}}<<";
   fb.len = 0;
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 
   // Test glob pattern in the RPC function name
@@ -687,6 +786,7 @@ static void test_rpc(void) {
   jsonrpc_export("Bar.*", foo3);
   fb.len = 0;
   jsonrpc_process(req, (int) strlen(req), mjson_print_fixed_buf, &fb, NULL);
+  ASSERT(fb.len > 0);
   ASSERT(strcmp(buf, res) == 0);
 }