diff --git a/src/ArduinoJson.hpp b/src/ArduinoJson.hpp
index 3c9488bf..f786694e 100644
--- a/src/ArduinoJson.hpp
+++ b/src/ArduinoJson.hpp
@@ -55,7 +55,7 @@ using ARDUINOJSON_NAMESPACE::JsonObject;
 using ARDUINOJSON_NAMESPACE::JsonObjectConst;
 using ARDUINOJSON_NAMESPACE::JsonPair;
 using ARDUINOJSON_NAMESPACE::JsonPairConst;
-typedef ARDUINOJSON_NAMESPACE::String JsonString;
+using ARDUINOJSON_NAMESPACE::JsonString;
 using ARDUINOJSON_NAMESPACE::JsonUInt;
 typedef ARDUINOJSON_NAMESPACE::VariantConstRef JsonVariantConst;
 typedef ARDUINOJSON_NAMESPACE::VariantRef JsonVariant;
diff --git a/src/ArduinoJson/Array/Utilities.hpp b/src/ArduinoJson/Array/Utilities.hpp
index cfcebe49..6984a45f 100644
--- a/src/ArduinoJson/Array/Utilities.hpp
+++ b/src/ArduinoJson/Array/Utilities.hpp
@@ -81,7 +81,7 @@ inline size_t copyArray(JsonArrayConst src, T* dst, size_t len) {
 // Special case for char[] which must be treated as a string
 template <size_t N>
 inline size_t copyArray(VariantConstRef src, char (&dst)[N]) {
-  String s = src;
+  JsonString s = src;
   size_t len = N - 1;
   if (len > s.size())
     len = s.size();
diff --git a/src/ArduinoJson/Collection/CollectionImpl.hpp b/src/ArduinoJson/Collection/CollectionImpl.hpp
index 634ab594..f933f527 100644
--- a/src/ArduinoJson/Collection/CollectionImpl.hpp
+++ b/src/ArduinoJson/Collection/CollectionImpl.hpp
@@ -60,7 +60,8 @@ inline bool CollectionData::copyFrom(const CollectionData& src,
   for (VariantSlot* s = src._head; s; s = s->next()) {
     VariantData* var;
     if (s->key() != 0) {
-      String key(s->key(), s->ownsKey() ? String::Copied : String::Linked);
+      JsonString key(s->key(),
+                     s->ownsKey() ? JsonString::Copied : JsonString::Linked);
       var = addMember(adaptString(key), pool);
     } else {
       var = addElement(pool);
diff --git a/src/ArduinoJson/Json/JsonDeserializer.hpp b/src/ArduinoJson/Json/JsonDeserializer.hpp
index 972bcb24..60fd0ad3 100644
--- a/src/ArduinoJson/Json/JsonDeserializer.hpp
+++ b/src/ArduinoJson/Json/JsonDeserializer.hpp
@@ -263,7 +263,7 @@ class JsonDeserializer {
       if (!eat(':'))
         return DeserializationError::InvalidInput;
 
-      String key = _stringStorage.str();
+      JsonString key = _stringStorage.str();
 
       TFilter memberFilter = filter[key.c_str()];
 
diff --git a/src/ArduinoJson/Memory/MemoryPool.hpp b/src/ArduinoJson/Memory/MemoryPool.hpp
index fe09a9f3..02af416d 100644
--- a/src/ArduinoJson/Memory/MemoryPool.hpp
+++ b/src/ArduinoJson/Memory/MemoryPool.hpp
@@ -222,7 +222,7 @@ template <typename TAdaptedString, typename TCallback>
 bool storeString(MemoryPool* pool, TAdaptedString str,
                  StringStoragePolicy::Copy, TCallback callback) {
   const char* copy = pool->saveString(str);
-  String storedString(copy, str.size(), String::Copied);
+  JsonString storedString(copy, str.size(), JsonString::Copied);
   callback(storedString);
   return copy != 0;
 }
@@ -230,7 +230,7 @@ bool storeString(MemoryPool* pool, TAdaptedString str,
 template <typename TAdaptedString, typename TCallback>
 bool storeString(MemoryPool*, TAdaptedString str, StringStoragePolicy::Link,
                  TCallback callback) {
-  String storedString(str.data(), str.size(), String::Linked);
+  JsonString storedString(str.data(), str.size(), JsonString::Linked);
   callback(storedString);
   return !str.isNull();
 }
diff --git a/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp b/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
index eb8d9ca5..425ee4f8 100644
--- a/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
+++ b/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
@@ -470,7 +470,7 @@ class MsgPackDeserializer {
       if (err)
         return err;
 
-      String key = _stringStorage.str();
+      JsonString key = _stringStorage.str();
       TFilter memberFilter = filter[key.c_str()];
       VariantData* member;
 
diff --git a/src/ArduinoJson/Object/JsonPair.hpp b/src/ArduinoJson/Object/JsonPair.hpp
index cad11d7e..0e840ee3 100644
--- a/src/ArduinoJson/Object/JsonPair.hpp
+++ b/src/ArduinoJson/Object/JsonPair.hpp
@@ -4,7 +4,7 @@
 
 #pragma once
 
-#include <ArduinoJson/Strings/String.hpp>
+#include <ArduinoJson/Strings/JsonString.hpp>
 #include <ArduinoJson/Variant/VariantConstRef.hpp>
 #include <ArduinoJson/Variant/VariantRef.hpp>
 
@@ -14,13 +14,13 @@ class JsonPair {
  public:
   JsonPair(MemoryPool* pool, VariantSlot* slot) {
     if (slot) {
-      _key = String(slot->key(),
-                    slot->ownsKey() ? String::Copied : String::Linked);
+      _key = JsonString(slot->key(), slot->ownsKey() ? JsonString::Copied
+                                                     : JsonString::Linked);
       _value = VariantRef(pool, slot->data());
     }
   }
 
-  String key() const {
+  JsonString key() const {
     return _key;
   }
 
@@ -29,7 +29,7 @@ class JsonPair {
   }
 
  private:
-  String _key;
+  JsonString _key;
   VariantRef _value;
 };
 
@@ -37,13 +37,13 @@ class JsonPairConst {
  public:
   JsonPairConst(const VariantSlot* slot) {
     if (slot) {
-      _key = String(slot->key(),
-                    slot->ownsKey() ? String::Copied : String::Linked);
+      _key = JsonString(slot->key(), slot->ownsKey() ? JsonString::Copied
+                                                     : JsonString::Linked);
       _value = VariantConstRef(slot->data());
     }
   }
 
-  String key() const {
+  JsonString key() const {
     return _key;
   }
 
@@ -52,7 +52,7 @@ class JsonPairConst {
   }
 
  private:
-  String _key;
+  JsonString _key;
   VariantConstRef _value;
 };
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/StringStorage/StringCopier.hpp b/src/ArduinoJson/StringStorage/StringCopier.hpp
index 2d161b96..ec61c4ed 100644
--- a/src/ArduinoJson/StringStorage/StringCopier.hpp
+++ b/src/ArduinoJson/StringStorage/StringCopier.hpp
@@ -19,10 +19,11 @@ class StringCopier {
       _pool->markAsOverflowed();
   }
 
-  String save() {
+  JsonString save() {
     ARDUINOJSON_ASSERT(_ptr);
     ARDUINOJSON_ASSERT(_size < _capacity);  // needs room for the terminator
-    return String(_pool->saveStringFromFreeZone(_size), _size, String::Copied);
+    return JsonString(_pool->saveStringFromFreeZone(_size), _size,
+                      JsonString::Copied);
   }
 
   void append(const char* s) {
@@ -48,11 +49,11 @@ class StringCopier {
     return _size;
   }
 
-  String str() const {
+  JsonString str() const {
     ARDUINOJSON_ASSERT(_ptr);
     ARDUINOJSON_ASSERT(_size < _capacity);
     _ptr[_size] = 0;
-    return String(_ptr, _size, String::Copied);
+    return JsonString(_ptr, _size, JsonString::Copied);
   }
 
  private:
diff --git a/src/ArduinoJson/StringStorage/StringMover.hpp b/src/ArduinoJson/StringStorage/StringMover.hpp
index f4cd1bae..688e9e27 100644
--- a/src/ArduinoJson/StringStorage/StringMover.hpp
+++ b/src/ArduinoJson/StringStorage/StringMover.hpp
@@ -5,7 +5,7 @@
 #pragma once
 
 #include <ArduinoJson/Namespace.hpp>
-#include <ArduinoJson/Strings/String.hpp>
+#include <ArduinoJson/Strings/JsonString.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
@@ -17,8 +17,8 @@ class StringMover {
     _startPtr = _writePtr;
   }
 
-  FORCE_INLINE String save() {
-    String s = str();
+  FORCE_INLINE JsonString save() {
+    JsonString s = str();
     _writePtr++;
     return s;
   }
@@ -31,9 +31,9 @@ class StringMover {
     return true;
   }
 
-  String str() const {
+  JsonString str() const {
     _writePtr[0] = 0;  // terminator
-    return String(_startPtr, size(), String::Linked);
+    return JsonString(_startPtr, size(), JsonString::Linked);
   }
 
   size_t size() const {
diff --git a/src/ArduinoJson/Strings/Adapters/JsonString.hpp b/src/ArduinoJson/Strings/Adapters/JsonString.hpp
index dec82a6b..69c18d11 100644
--- a/src/ArduinoJson/Strings/Adapters/JsonString.hpp
+++ b/src/ArduinoJson/Strings/Adapters/JsonString.hpp
@@ -5,14 +5,14 @@
 #pragma once
 
 #include <ArduinoJson/Strings/Adapters/RamString.hpp>
-#include <ArduinoJson/Strings/String.hpp>
+#include <ArduinoJson/Strings/JsonString.hpp>
 #include <ArduinoJson/Strings/StringAdapter.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
 class JsonStringAdapter : public SizedRamString {
  public:
-  JsonStringAdapter(const String& s)
+  JsonStringAdapter(const JsonString& s)
       : SizedRamString(s.c_str(), s.size()), _linked(s.isLinked()) {}
 
   StringStoragePolicy::LinkOrCopy storagePolicy() {
@@ -25,10 +25,10 @@ class JsonStringAdapter : public SizedRamString {
 };
 
 template <>
-struct StringAdapter<String> {
+struct StringAdapter<JsonString> {
   typedef JsonStringAdapter AdaptedString;
 
-  static AdaptedString adapt(const String& s) {
+  static AdaptedString adapt(const JsonString& s) {
     return AdaptedString(s);
   }
 };
diff --git a/src/ArduinoJson/Strings/String.hpp b/src/ArduinoJson/Strings/JsonString.hpp
similarity index 74%
rename from src/ArduinoJson/Strings/String.hpp
rename to src/ArduinoJson/Strings/JsonString.hpp
index 1371114e..bb42c5c4 100644
--- a/src/ArduinoJson/Strings/String.hpp
+++ b/src/ArduinoJson/Strings/JsonString.hpp
@@ -12,16 +12,16 @@
 
 namespace ARDUINOJSON_NAMESPACE {
 
-class String : public SafeBoolIdom<String> {
+class JsonString : public SafeBoolIdom<JsonString> {
  public:
   enum Ownership { Copied, Linked };
 
-  String() : _data(0), _size(0), _ownership(Linked) {}
+  JsonString() : _data(0), _size(0), _ownership(Linked) {}
 
-  String(const char* data, Ownership ownership = Linked)
+  JsonString(const char* data, Ownership ownership = Linked)
       : _data(data), _size(data ? ::strlen(data) : 0), _ownership(ownership) {}
 
-  String(const char* data, size_t sz, Ownership ownership = Linked)
+  JsonString(const char* data, size_t sz, Ownership ownership = Linked)
       : _data(data), _size(sz), _ownership(ownership) {}
 
   const char* c_str() const {
@@ -45,7 +45,7 @@ class String : public SafeBoolIdom<String> {
     return _data ? safe_true() : safe_false();
   }
 
-  friend bool operator==(String lhs, String rhs) {
+  friend bool operator==(JsonString lhs, JsonString rhs) {
     if (lhs._size != rhs._size)
       return false;
     if (lhs._data == rhs._data)
@@ -57,12 +57,12 @@ class String : public SafeBoolIdom<String> {
     return memcmp(lhs._data, rhs._data, lhs._size) == 0;
   }
 
-  friend bool operator!=(String lhs, String rhs) {
+  friend bool operator!=(JsonString lhs, JsonString rhs) {
     return !(lhs == rhs);
   }
 
 #if ARDUINOJSON_ENABLE_STD_STREAM
-  friend std::ostream& operator<<(std::ostream& lhs, const String& rhs) {
+  friend std::ostream& operator<<(std::ostream& lhs, const JsonString& rhs) {
     lhs.write(rhs.c_str(), static_cast<std::streamsize>(rhs.size()));
     return lhs;
   }
diff --git a/src/ArduinoJson/Variant/ConverterImpl.hpp b/src/ArduinoJson/Variant/ConverterImpl.hpp
index e12fff30..16d5059f 100644
--- a/src/ArduinoJson/Variant/ConverterImpl.hpp
+++ b/src/ArduinoJson/Variant/ConverterImpl.hpp
@@ -133,12 +133,12 @@ struct Converter<const char*> : private VariantAttorney {
 };
 
 template <>
-struct Converter<String> : private VariantAttorney {
-  static void toJson(String src, VariantRef dst) {
+struct Converter<JsonString> : private VariantAttorney {
+  static void toJson(JsonString src, VariantRef dst) {
     variantSetString(getData(dst), adaptString(src), getPool(dst));
   }
 
-  static String fromJson(VariantConstRef src) {
+  static JsonString fromJson(VariantConstRef src) {
     const VariantData* data = getData(src);
     return data ? data->asString() : 0;
   }
@@ -207,9 +207,10 @@ class MemoryPoolPrint : public Print {
     pool->getFreeZone(&_string, &_capacity);
   }
 
-  String str() {
+  JsonString str() {
     ARDUINOJSON_ASSERT(_size < _capacity);
-    return String(_pool->saveStringFromFreeZone(_size), _size, String::Copied);
+    return JsonString(_pool->saveStringFromFreeZone(_size), _size,
+                      JsonString::Copied);
   }
 
   size_t write(uint8_t c) {
@@ -261,7 +262,7 @@ inline void convertToJson(const ::Printable& src, VariantRef dst) {
 #if ARDUINOJSON_ENABLE_ARDUINO_STRING
 
 inline void convertFromJson(VariantConstRef src, ::String& dst) {
-  String str = src.as<String>();
+  JsonString str = src.as<JsonString>();
   if (str)
     dst = str.c_str();
   else
@@ -269,7 +270,7 @@ inline void convertFromJson(VariantConstRef src, ::String& dst) {
 }
 
 inline bool canConvertFromJson(VariantConstRef src, const ::String&) {
-  return src.is<String>();
+  return src.is<JsonString>();
 }
 
 #endif
@@ -277,7 +278,7 @@ inline bool canConvertFromJson(VariantConstRef src, const ::String&) {
 #if ARDUINOJSON_ENABLE_STD_STRING
 
 inline void convertFromJson(VariantConstRef src, std::string& dst) {
-  String str = src.as<String>();
+  JsonString str = src.as<JsonString>();
   if (str)
     dst.assign(str.c_str(), str.size());
   else
@@ -285,7 +286,7 @@ inline void convertFromJson(VariantConstRef src, std::string& dst) {
 }
 
 inline bool canConvertFromJson(VariantConstRef src, const std::string&) {
-  return src.is<String>();
+  return src.is<JsonString>();
 }
 
 #endif
@@ -293,13 +294,13 @@ inline bool canConvertFromJson(VariantConstRef src, const std::string&) {
 #if ARDUINOJSON_ENABLE_STRING_VIEW
 
 inline void convertFromJson(VariantConstRef src, std::string_view& dst) {
-  String str = src.as<String>();
+  JsonString str = src.as<JsonString>();
   if (str)  // the standard doesn't allow passing null to the constructor
     dst = std::string_view(str.c_str(), str.size());
 }
 
 inline bool canConvertFromJson(VariantConstRef src, const std::string_view&) {
-  return src.is<String>();
+  return src.is<JsonString>();
 }
 
 #endif
diff --git a/src/ArduinoJson/Variant/VariantData.hpp b/src/ArduinoJson/Variant/VariantData.hpp
index 7e0a653b..d086accc 100644
--- a/src/ArduinoJson/Variant/VariantData.hpp
+++ b/src/ArduinoJson/Variant/VariantData.hpp
@@ -7,7 +7,7 @@
 #include <ArduinoJson/Memory/MemoryPool.hpp>
 #include <ArduinoJson/Misc/SerializedValue.hpp>
 #include <ArduinoJson/Numbers/convertNumber.hpp>
-#include <ArduinoJson/Strings/String.hpp>
+#include <ArduinoJson/Strings/JsonString.hpp>
 #include <ArduinoJson/Strings/StringAdapters.hpp>
 #include <ArduinoJson/Variant/VariantContent.hpp>
 
@@ -84,7 +84,7 @@ class VariantData {
   template <typename T>
   T asFloat() const;
 
-  String asString() const;
+  JsonString asString() const;
 
   bool asBoolean() const;
 
@@ -217,7 +217,7 @@ class VariantData {
     setType(VALUE_IS_NULL);
   }
 
-  void setString(String s) {
+  void setString(JsonString s) {
     ARDUINOJSON_ASSERT(s);
     if (s.isLinked())
       setType(VALUE_IS_LINKED_STRING);
diff --git a/src/ArduinoJson/Variant/VariantImpl.hpp b/src/ArduinoJson/Variant/VariantImpl.hpp
index 9479537f..b2f04e05 100644
--- a/src/ArduinoJson/Variant/VariantImpl.hpp
+++ b/src/ArduinoJson/Variant/VariantImpl.hpp
@@ -70,16 +70,16 @@ inline T VariantData::asFloat() const {
   }
 }
 
-inline String VariantData::asString() const {
+inline JsonString VariantData::asString() const {
   switch (type()) {
     case VALUE_IS_LINKED_STRING:
-      return String(_content.asString.data, _content.asString.size,
-                    String::Linked);
+      return JsonString(_content.asString.data, _content.asString.size,
+                        JsonString::Linked);
     case VALUE_IS_OWNED_STRING:
-      return String(_content.asString.data, _content.asString.size,
-                    String::Copied);
+      return JsonString(_content.asString.data, _content.asString.size,
+                        JsonString::Copied);
     default:
-      return String();
+      return JsonString();
   }
 }
 
@@ -90,7 +90,7 @@ inline bool VariantData::copyFrom(const VariantData& src, MemoryPool* pool) {
     case VALUE_IS_OBJECT:
       return toObject().copyFrom(src._content.asCollection, pool);
     case VALUE_IS_OWNED_STRING: {
-      String value = src.asString();
+      JsonString value = src.asString();
       return setString(adaptString(value), pool);
     }
     case VALUE_IS_OWNED_RAW:
diff --git a/src/ArduinoJson/Variant/VariantSlot.hpp b/src/ArduinoJson/Variant/VariantSlot.hpp
index 83ff1d78..5cd53bd3 100644
--- a/src/ArduinoJson/Variant/VariantSlot.hpp
+++ b/src/ArduinoJson/Variant/VariantSlot.hpp
@@ -76,7 +76,7 @@ class VariantSlot {
     _next = VariantSlotDiff(slot - this);
   }
 
-  void setKey(String k) {
+  void setKey(JsonString k) {
     ARDUINOJSON_ASSERT(k);
     if (k.isLinked())
       _flags &= VALUE_MASK;