diff --git a/ReactCommon/cxxreact/JSCExecutor.cpp b/ReactCommon/cxxreact/JSCExecutor.cpp
index 536313da4..c244532ac 100644
--- a/ReactCommon/cxxreact/JSCExecutor.cpp
+++ b/ReactCommon/cxxreact/JSCExecutor.cpp
@@ -93,7 +93,7 @@ static JSValueRef nativeInjectHMRUpdate(
 static std::string executeJSCallWithJSC(
     JSGlobalContextRef ctx,
     const std::string& methodName,
-    const std::vector<folly::dynamic>& arguments) {
+    const std::vector<folly::dynamic>& arguments) throw(JSException) {
   SystraceSection s("JSCExecutor.executeJSCall",
                     "method", methodName);
 
@@ -115,7 +115,7 @@ std::unique_ptr<JSExecutor> JSCExecutorFactory::createJSExecutor(
 JSCExecutor::JSCExecutor(std::shared_ptr<ExecutorDelegate> delegate,
                          std::shared_ptr<MessageQueueThread> messageQueueThread,
                          const std::string& cacheDir,
-                         const folly::dynamic& jscConfig) :
+                         const folly::dynamic& jscConfig) throw(JSException) :
     m_delegate(delegate),
     m_deviceCacheDir(cacheDir),
     m_messageQueueThread(messageQueueThread),
@@ -199,7 +199,7 @@ void JSCExecutor::destroy() {
   });
 }
 
-void JSCExecutor::initOnJSVMThread() {
+void JSCExecutor::initOnJSVMThread() throw(JSException) {
   SystraceSection s("JSCExecutor.initOnJSVMThread");
 
   #if defined(WITH_FB_JSC_TUNING)
@@ -269,7 +269,7 @@ void JSCExecutor::terminateOnJSVMThread() {
   m_context = nullptr;
 }
 
-void JSCExecutor::loadApplicationScript(std::unique_ptr<const JSBigString> script, std::string sourceURL) {
+void JSCExecutor::loadApplicationScript(std::unique_ptr<const JSBigString> script, std::string sourceURL) throw(JSException) {
   SystraceSection s("JSCExecutor::loadApplicationScript",
                     "sourceURL", sourceURL);
 
@@ -300,14 +300,15 @@ void JSCExecutor::setJSModulesUnbundle(std::unique_ptr<JSModulesUnbundle> unbund
   m_unbundle = std::move(unbundle);
 }
 
-void JSCExecutor::flush() {
+void JSCExecutor::flush() throw(JSException) {
   // TODO: Make this a first class function instead of evaling. #9317773
   std::string calls = executeJSCallWithJSC(m_context, "flushedQueue", std::vector<folly::dynamic>());
   m_delegate->callNativeModules(*this, std::move(calls), true);
 }
 
-void JSCExecutor::callFunction(const std::string& moduleId, const std::string& methodId, const folly::dynamic& arguments) {
+void JSCExecutor::callFunction(const std::string& moduleId, const std::string& methodId, const folly::dynamic& arguments) throw(JSException) {
   // TODO:  Make this a first class function instead of evaling. #9317773
+  // TODO(cjhopman): This copies args.
   std::vector<folly::dynamic> call{
     moduleId,
     methodId,
@@ -317,8 +318,9 @@ void JSCExecutor::callFunction(const std::string& moduleId, const std::string& m
   m_delegate->callNativeModules(*this, std::move(calls), true);
 }
 
-void JSCExecutor::invokeCallback(const double callbackId, const folly::dynamic& arguments) {
+void JSCExecutor::invokeCallback(const double callbackId, const folly::dynamic& arguments) throw(JSException) {
   // TODO: Make this a first class function instead of evaling. #9317773
+  // TODO(cjhopman): This copies args.
   std::vector<folly::dynamic> call{
     (double) callbackId,
     std::move(arguments)
@@ -327,7 +329,7 @@ void JSCExecutor::invokeCallback(const double callbackId, const folly::dynamic&
   m_delegate->callNativeModules(*this, std::move(calls), true);
 }
 
-void JSCExecutor::setGlobalVariable(std::string propName, std::unique_ptr<const JSBigString> jsonValue) {
+void JSCExecutor::setGlobalVariable(std::string propName, std::unique_ptr<const JSBigString> jsonValue) throw(JSException) {
   SystraceSection s("JSCExecutor.setGlobalVariable",
                     "propName", propName);
 
diff --git a/ReactCommon/cxxreact/JSCExecutor.h b/ReactCommon/cxxreact/JSCExecutor.h
index 735e1c45e..816bec1a5 100644
--- a/ReactCommon/cxxreact/JSCExecutor.h
+++ b/ReactCommon/cxxreact/JSCExecutor.h
@@ -52,24 +52,24 @@ public:
   explicit JSCExecutor(std::shared_ptr<ExecutorDelegate> delegate,
                        std::shared_ptr<MessageQueueThread> messageQueueThread,
                        const std::string& cacheDir,
-                       const folly::dynamic& jscConfig);
+                       const folly::dynamic& jscConfig) throw(JSException);
   ~JSCExecutor() override;
 
   virtual void loadApplicationScript(
     std::unique_ptr<const JSBigString> script,
-    std::string sourceURL) override;
+    std::string sourceURL) throw(JSException) override;
   virtual void setJSModulesUnbundle(
     std::unique_ptr<JSModulesUnbundle> unbundle) override;
   virtual void callFunction(
     const std::string& moduleId,
     const std::string& methodId,
-    const folly::dynamic& arguments) override;
+    const folly::dynamic& arguments) throw(JSException) override;
   virtual void invokeCallback(
     const double callbackId,
-    const folly::dynamic& arguments) override;
+    const folly::dynamic& arguments) throw(JSException) override;
   virtual void setGlobalVariable(
     std::string propName,
-    std::unique_ptr<const JSBigString> jsonValue) override;
+    std::unique_ptr<const JSBigString> jsonValue) throw(JSException) override;
   virtual void* getJavaScriptContext() override;
   virtual bool supportsProfiling() override;
   virtual void startProfiler(const std::string &titleString) override;
@@ -103,9 +103,9 @@ private:
       std::unordered_map<std::string, std::string> globalObjAsJSON,
       const folly::dynamic& jscConfig);
 
-  void initOnJSVMThread();
+  void initOnJSVMThread() throw(JSException);
   void terminateOnJSVMThread();
-  void flush();
+  void flush() throw(JSException);
   void flushQueueImmediate(std::string queueJSON);
   void loadModule(uint32_t moduleId);
 
diff --git a/ReactCommon/cxxreact/JSCHelpers.h b/ReactCommon/cxxreact/JSCHelpers.h
index eb29058ef..0d2609a75 100644
--- a/ReactCommon/cxxreact/JSCHelpers.h
+++ b/ReactCommon/cxxreact/JSCHelpers.h
@@ -12,29 +12,9 @@
 #include <stdexcept>
 #include <algorithm>
 
-#include "Value.h"
-
 namespace facebook {
 namespace react {
 
-class JSException : public std::runtime_error {
-public:
-  explicit JSException(const char* msg)
-    : std::runtime_error(msg)
-    , stack_("") {}
-
-  JSException(const char* msg, const char* stack)
-    : std::runtime_error(msg)
-    , stack_(stack) {}
-
-  const std::string& getStack() const {
-    return stack_;
-  }
-
-private:
-  std::string stack_;
-};
-
 inline void throwJSExecutionException(const char* msg) {
   throw JSException(msg);
 }
diff --git a/ReactCommon/cxxreact/MethodCall.cpp b/ReactCommon/cxxreact/MethodCall.cpp
index 2782e05b6..efb142c6c 100644
--- a/ReactCommon/cxxreact/MethodCall.cpp
+++ b/ReactCommon/cxxreact/MethodCall.cpp
@@ -13,7 +13,7 @@ namespace react {
 #define REQUEST_PARAMSS 2
 #define REQUEST_CALLID 3
 
-std::vector<MethodCall> parseMethodCalls(const std::string& json) {
+std::vector<MethodCall> parseMethodCalls(const std::string& json) throw(std::invalid_argument) {
   folly::dynamic jsonData = folly::parseJson(json);
 
   if (jsonData.isNull()) {
diff --git a/ReactCommon/cxxreact/MethodCall.h b/ReactCommon/cxxreact/MethodCall.h
index 02e86eb98..a28bf40e5 100644
--- a/ReactCommon/cxxreact/MethodCall.h
+++ b/ReactCommon/cxxreact/MethodCall.h
@@ -24,6 +24,6 @@ struct MethodCall {
     , callId(cid) {}
 };
 
-std::vector<MethodCall> parseMethodCalls(const std::string& json);
+std::vector<MethodCall> parseMethodCalls(const std::string& json) throw(std::invalid_argument);
 
 } }
diff --git a/ReactCommon/cxxreact/Value.cpp b/ReactCommon/cxxreact/Value.cpp
index a8ccf6614..9b236b0ce 100644
--- a/ReactCommon/cxxreact/Value.cpp
+++ b/ReactCommon/cxxreact/Value.cpp
@@ -30,7 +30,7 @@ JSContextRef Value::context() const {
   return m_context;
 }
 
-std::string Value::toJSONString(unsigned indent) const {
+std::string Value::toJSONString(unsigned indent) const throw(JSException) {
   JSValueRef exn;
   auto stringToAdopt = JSValueCreateJSONString(m_context, m_value, indent, &exn);
   if (stringToAdopt == nullptr) {
@@ -41,7 +41,7 @@ std::string Value::toJSONString(unsigned indent) const {
 }
 
 /* static */
-Value Value::fromJSON(JSContextRef ctx, const String& json) {
+Value Value::fromJSON(JSContextRef ctx, const String& json) throw(JSException) {
   auto result = JSValueMakeFromJSONString(ctx, json);
   if (!result) {
     throwJSExecutionException("Failed to create String from JSON");
diff --git a/ReactCommon/cxxreact/Value.h b/ReactCommon/cxxreact/Value.h
index 7813f0839..6291aabbe 100644
--- a/ReactCommon/cxxreact/Value.h
+++ b/ReactCommon/cxxreact/Value.h
@@ -24,6 +24,25 @@ namespace react {
 class Value;
 class Context;
 
+class JSException : public std::runtime_error {
+public:
+  explicit JSException(const char* msg)
+    : std::runtime_error(msg)
+    , stack_("") {}
+
+  JSException(const char* msg, const char* stack)
+    : std::runtime_error(msg)
+    , stack_(stack) {}
+
+  const std::string& getStack() const {
+    return stack_;
+  }
+
+private:
+  std::string stack_;
+};
+
+
 class String : public noncopyable {
 public:
   explicit String(const char* utf8) :
@@ -228,12 +247,12 @@ public:
     return JSValueIsString(context(), m_value);
   }
 
-  String toString() {
+  String toString() noexcept {
     return String::adopt(JSValueToStringCopy(context(), m_value, nullptr));
   }
 
-  std::string toJSONString(unsigned indent = 0) const;
-  static Value fromJSON(JSContextRef ctx, const String& json);
+  std::string toJSONString(unsigned indent = 0) const throw(JSException);
+  static Value fromJSON(JSContextRef ctx, const String& json) throw(JSException);
 protected:
   JSContextRef context() const;
   JSContextRef m_context;