diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9144c7a4..e2009f11 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,14 @@
 ArduinoJson: change log
 =======================
 
+HEAD
+----
+
+* Fixed an integer overflow in the JSON deserializer
+* Added overflow handling in `JsonVariant::as<T>()` and `JsonVariant::is<T>()`.
+   - `as<T>()` returns `0` if the integer `T` overflows
+   - `is<T>()` returns `false` if the integer `T` overflows
+
 v6.9.1 (2019-03-01)
 ------
 
diff --git a/fuzzing/json_seed_corpus/IntegerOverflow.json b/fuzzing/json_seed_corpus/IntegerOverflow.json
new file mode 100644
index 00000000..3a33cb89
--- /dev/null
+++ b/fuzzing/json_seed_corpus/IntegerOverflow.json
@@ -0,0 +1 @@
+9720730739393920739
diff --git a/scripts/travis/fuzz.sh b/scripts/travis/fuzz.sh
index 48e9728e..1d4e32d9 100755
--- a/scripts/travis/fuzz.sh
+++ b/scripts/travis/fuzz.sh
@@ -3,7 +3,7 @@
 ROOT_DIR=$(dirname $0)/../../
 INCLUDE_DIR=${ROOT_DIR}/src/
 FUZZING_DIR=${ROOT_DIR}/fuzzing/
-CXXFLAGS="-g -fprofile-instr-generate -fcoverage-mapping -fsanitize=address,fuzzer"
+CXXFLAGS="-g -fprofile-instr-generate -fcoverage-mapping -fsanitize=address,undefined,fuzzer -fno-sanitize-recover=all"
 
 fuzz() {
 	NAME="$1"
diff --git a/src/ArduinoJson/Json/JsonDeserializer.hpp b/src/ArduinoJson/Json/JsonDeserializer.hpp
index 415b807b..ba9ab03c 100644
--- a/src/ArduinoJson/Json/JsonDeserializer.hpp
+++ b/src/ArduinoJson/Json/JsonDeserializer.hpp
@@ -6,8 +6,7 @@
 
 #include "../Deserialization/deserialize.hpp"
 #include "../Memory/MemoryPool.hpp"
-#include "../Numbers/isFloat.hpp"
-#include "../Numbers/isInteger.hpp"
+#include "../Numbers/parseNumber.hpp"
 #include "../Polyfills/type_traits.hpp"
 #include "../Variant/VariantData.hpp"
 #include "EscapeSequence.hpp"
@@ -251,14 +250,6 @@ class JsonDeserializer {
     }
     buffer[n] = 0;
 
-    if (isInteger(buffer)) {
-      result.setInteger(parseInteger<Integer>(buffer));
-      return DeserializationError::Ok;
-    }
-    if (isFloat(buffer)) {
-      result.setFloat(parseFloat<Float>(buffer));
-      return DeserializationError::Ok;
-    }
     c = buffer[0];
     if (c == 't') {  // true
       result.setBoolean(true);
@@ -275,6 +266,23 @@ class JsonDeserializer {
       return n == 4 ? DeserializationError::Ok
                     : DeserializationError::IncompleteInput;
     }
+
+    ParsedNumber<Float, UInt> num = parseNumber<Float, UInt>(buffer);
+
+    switch (num.type()) {
+      case VALUE_IS_NEGATIVE_INTEGER:
+        result.setNegativeInteger(num.uintValue);
+        return DeserializationError::Ok;
+
+      case VALUE_IS_POSITIVE_INTEGER:
+        result.setPositiveInteger(num.uintValue);
+        return DeserializationError::Ok;
+
+      case VALUE_IS_FLOAT:
+        result.setFloat(num.floatValue);
+        return DeserializationError::Ok;
+    }
+
     return DeserializationError::InvalidInput;
   }
 
diff --git a/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp b/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
index 9244ecb2..70c9e94f 100644
--- a/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
+++ b/src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp
@@ -79,8 +79,7 @@ class MsgPackDeserializer {
 #if ARDUINOJSON_USE_LONG_LONG
         return readInteger<uint64_t>(variant);
 #else
-        readInteger<uint32_t>();
-        return readInteger<uint32_t>(variant);
+        return DeserializationError::NotSupported;
 #endif
 
       case 0xd0:
@@ -96,8 +95,7 @@ class MsgPackDeserializer {
 #if ARDUINOJSON_USE_LONG_LONG
         return readInteger<int64_t>(variant);
 #else
-        if (!skip(4)) return DeserializationError::IncompleteInput;
-        return readInteger<int32_t>(variant);
+        return DeserializationError::NotSupported;
 #endif
 
       case 0xca:
diff --git a/src/ArduinoJson/MsgPack/MsgPackSerializer.hpp b/src/ArduinoJson/MsgPack/MsgPackSerializer.hpp
index 8c9f3b22..10edb107 100644
--- a/src/ArduinoJson/MsgPack/MsgPackSerializer.hpp
+++ b/src/ArduinoJson/MsgPack/MsgPackSerializer.hpp
@@ -24,7 +24,8 @@ class MsgPackSerializer {
   }
 
   template <typename T>
-  typename enable_if<sizeof(T) == 8>::type visitFloat(T value64) {
+  typename enable_if<sizeof(T) == 8>::type visitFloat(T value64)
+      ARDUINOJSON_NO_SANITIZE("float-cast-overflow") {
     float value32 = float(value64);
     if (value32 == value64) {
       writeByte(0xCA);
diff --git a/src/ArduinoJson/Numbers/FloatTraits.hpp b/src/ArduinoJson/Numbers/FloatTraits.hpp
index 73c8bbd8..2e92fb7c 100644
--- a/src/ArduinoJson/Numbers/FloatTraits.hpp
+++ b/src/ArduinoJson/Numbers/FloatTraits.hpp
@@ -17,10 +17,10 @@ struct FloatTraits {};
 
 template <typename T>
 struct FloatTraits<T, 8 /*64bits*/> {
-  typedef int64_t mantissa_type;
+  typedef uint64_t mantissa_type;
   static const short mantissa_bits = 52;
   static const mantissa_type mantissa_max =
-      (static_cast<mantissa_type>(1) << mantissa_bits) - 1;
+      (mantissa_type(1) << mantissa_bits) - 1;
 
   typedef int16_t exponent_type;
   static const exponent_type exponent_max = 308;
@@ -95,6 +95,14 @@ struct FloatTraits<T, 8 /*64bits*/> {
     return forge(0x7ff00000, 0x00000000);
   }
 
+  static T highest() {
+    return forge(0x7FEFFFFF, 0xFFFFFFFF);
+  }
+
+  static T lowest() {
+    return forge(0xFFEFFFFF, 0xFFFFFFFF);
+  }
+
   // constructs a double floating point values from its binary representation
   // we use this function to workaround platforms with single precision literals
   // (for example, when -fsingle-precision-constant is passed to GCC)
@@ -105,10 +113,10 @@ struct FloatTraits<T, 8 /*64bits*/> {
 
 template <typename T>
 struct FloatTraits<T, 4 /*32bits*/> {
-  typedef int32_t mantissa_type;
+  typedef uint32_t mantissa_type;
   static const short mantissa_bits = 23;
   static const mantissa_type mantissa_max =
-      (static_cast<mantissa_type>(1) << mantissa_bits) - 1;
+      (mantissa_type(1) << mantissa_bits) - 1;
 
   typedef int8_t exponent_type;
   static const exponent_type exponent_max = 38;
@@ -156,5 +164,13 @@ struct FloatTraits<T, 4 /*32bits*/> {
   static T inf() {
     return forge(0x7f800000);
   }
+
+  static T highest() {
+    return forge(0x7f7fffff);
+  }
+
+  static T lowest() {
+    return forge(0xFf7fffff);
+  }
 };
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/convertNumber.hpp b/src/ArduinoJson/Numbers/convertNumber.hpp
new file mode 100644
index 00000000..4d92822d
--- /dev/null
+++ b/src/ArduinoJson/Numbers/convertNumber.hpp
@@ -0,0 +1,105 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#pragma once
+
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wconversion"
+#elif defined(__GNUC__)
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+#pragma GCC diagnostic push
+#endif
+#pragma GCC diagnostic ignored "-Wconversion"
+#endif
+
+#include "../Polyfills/limits.hpp"
+#include "Float.hpp"
+#include "FloatTraits.hpp"
+#include "Integer.hpp"
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <typename TOut, typename TIn>
+typename enable_if<is_integral<TOut>::value && sizeof(TOut) <= sizeof(TIn),
+                   bool>::type
+canStorePositiveInteger(TIn value) {
+  return value <= TIn(numeric_limits<TOut>::highest());
+}
+
+template <typename TOut, typename TIn>
+typename enable_if<is_integral<TOut>::value && sizeof(TIn) < sizeof(TOut),
+                   bool>::type
+canStorePositiveInteger(TIn) {
+  return true;
+}
+
+template <typename TOut, typename TIn>
+typename enable_if<is_floating_point<TOut>::value, bool>::type
+canStorePositiveInteger(TIn) {
+  return true;
+}
+
+template <typename TOut, typename TIn>
+typename enable_if<is_floating_point<TOut>::value, bool>::type
+canStoreNegativeInteger(TIn) {
+  return true;
+}
+
+template <typename TOut, typename TIn>
+typename enable_if<is_integral<TOut>::value && is_signed<TOut>::value &&
+                       sizeof(TOut) <= sizeof(TIn),
+                   bool>::type
+canStoreNegativeInteger(TIn value) {
+  return value <= TIn(numeric_limits<TOut>::highest()) + 1;
+}
+
+template <typename TOut, typename TIn>
+typename enable_if<is_integral<TOut>::value && is_signed<TOut>::value &&
+                       sizeof(TIn) < sizeof(TOut),
+                   bool>::type
+canStoreNegativeInteger(TIn) {
+  return true;
+}
+
+template <typename TOut, typename TIn>
+typename enable_if<is_integral<TOut>::value && is_unsigned<TOut>::value,
+                   bool>::type
+canStoreNegativeInteger(TIn) {
+  return false;
+}
+
+template <typename TOut, typename TIn>
+TOut convertPositiveInteger(TIn value) {
+  return canStorePositiveInteger<TOut>(value) ? TOut(value) : 0;
+}
+
+template <typename TOut, typename TIn>
+TOut convertNegativeInteger(TIn value) {
+  return canStoreNegativeInteger<TOut>(value) ? TOut(~value + 1) : 0;
+}
+
+template <typename TOut, typename TIn>
+typename enable_if<is_floating_point<TOut>::value, TOut>::type convertFloat(
+    TIn value) {
+  return TOut(value);
+}
+
+template <typename TOut, typename TIn>
+typename enable_if<!is_floating_point<TOut>::value, TOut>::type convertFloat(
+    TIn value) {
+  return value >= numeric_limits<TOut>::lowest() &&
+                 value <= numeric_limits<TOut>::highest()
+             ? TOut(value)
+             : 0;
+}
+}  // namespace ARDUINOJSON_NAMESPACE
+
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__)
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+#pragma GCC diagnostic pop
+#endif
+#endif
diff --git a/src/ArduinoJson/Numbers/isFloat.hpp b/src/ArduinoJson/Numbers/isFloat.hpp
deleted file mode 100644
index efaa55bc..00000000
--- a/src/ArduinoJson/Numbers/isFloat.hpp
+++ /dev/null
@@ -1,36 +0,0 @@
-// ArduinoJson - arduinojson.org
-// Copyright Benoit Blanchon 2014-2019
-// MIT License
-
-#pragma once
-
-#include <string.h>  // for strcmp
-#include "../Polyfills/ctype.hpp"
-
-namespace ARDUINOJSON_NAMESPACE {
-
-inline bool isFloat(const char* s) {
-  if (!s) return false;
-
-  if (!strcmp(s, "NaN")) return true;
-  if (issign(*s)) s++;
-  if (!strcmp(s, "Infinity")) return true;
-  if (*s == '\0') return false;
-
-  while (isdigit(*s)) s++;
-
-  if (*s == '.') {
-    s++;
-    while (isdigit(*s)) s++;
-  }
-
-  if (*s == 'e' || *s == 'E') {
-    s++;
-    if (issign(*s)) s++;
-    if (!isdigit(*s)) return false;
-    while (isdigit(*s)) s++;
-  }
-
-  return *s == '\0';
-}
-}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/isInteger.hpp b/src/ArduinoJson/Numbers/isInteger.hpp
deleted file mode 100644
index 620f381b..00000000
--- a/src/ArduinoJson/Numbers/isInteger.hpp
+++ /dev/null
@@ -1,17 +0,0 @@
-// ArduinoJson - arduinojson.org
-// Copyright Benoit Blanchon 2014-2019
-// MIT License
-
-#pragma once
-
-#include "../Polyfills/ctype.hpp"
-
-namespace ARDUINOJSON_NAMESPACE {
-
-inline bool isInteger(const char* s) {
-  if (!s || !*s) return false;
-  if (issign(*s)) s++;
-  while (isdigit(*s)) s++;
-  return *s == '\0';
-}
-}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/parseFloat.hpp b/src/ArduinoJson/Numbers/parseFloat.hpp
index 3f30885f..ea89c7ee 100644
--- a/src/ArduinoJson/Numbers/parseFloat.hpp
+++ b/src/ArduinoJson/Numbers/parseFloat.hpp
@@ -4,85 +4,15 @@
 
 #pragma once
 
-#include "../Numbers/FloatTraits.hpp"
-#include "../Polyfills/ctype.hpp"
-#include "../Polyfills/math.hpp"
+#include "convertNumber.hpp"
+#include "parseNumber.hpp"
 
 namespace ARDUINOJSON_NAMESPACE {
 
 template <typename T>
 inline T parseFloat(const char* s) {
-  typedef FloatTraits<T> traits;
-  typedef typename traits::mantissa_type mantissa_t;
-  typedef typename traits::exponent_type exponent_t;
-
-  if (!s) return 0;  // NULL
-
-  bool negative_result = false;
-  switch (*s) {
-    case '-':
-      negative_result = true;
-      s++;
-      break;
-    case '+':
-      s++;
-      break;
-  }
-
-  if (*s == 't') return 1;  // true
-  if (*s == 'n' || *s == 'N') return traits::nan();
-  if (*s == 'i' || *s == 'I')
-    return negative_result ? -traits::inf() : traits::inf();
-
-  mantissa_t mantissa = 0;
-  exponent_t exponent_offset = 0;
-
-  while (isdigit(*s)) {
-    if (mantissa < traits::mantissa_max / 10)
-      mantissa = mantissa * 10 + (*s - '0');
-    else
-      exponent_offset++;
-    s++;
-  }
-
-  if (*s == '.') {
-    s++;
-    while (isdigit(*s)) {
-      if (mantissa < traits::mantissa_max / 10) {
-        mantissa = mantissa * 10 + (*s - '0');
-        exponent_offset--;
-      }
-      s++;
-    }
-  }
-
-  int exponent = 0;
-  if (*s == 'e' || *s == 'E') {
-    s++;
-    bool negative_exponent = false;
-    if (*s == '-') {
-      negative_exponent = true;
-      s++;
-    } else if (*s == '+') {
-      s++;
-    }
-
-    while (isdigit(*s)) {
-      exponent = exponent * 10 + (*s - '0');
-      if (exponent + exponent_offset > traits::exponent_max) {
-        if (negative_exponent)
-          return negative_result ? -0.0f : 0.0f;
-        else
-          return negative_result ? -traits::inf() : traits::inf();
-      }
-      s++;
-    }
-    if (negative_exponent) exponent = -exponent;
-  }
-  exponent += exponent_offset;
-
-  T result = traits::make_float(static_cast<T>(mantissa), exponent);
-
-  return negative_result ? -result : result;
+  // try to reuse the same parameters as JsonDeserializer
+  typedef typename choose_largest<Float, T>::type TFloat;
+  return parseNumber<TFloat, UInt>(s).template as<T>();
 }
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/parseInteger.hpp b/src/ArduinoJson/Numbers/parseInteger.hpp
index 9bc40910..d3749a5c 100644
--- a/src/ArduinoJson/Numbers/parseInteger.hpp
+++ b/src/ArduinoJson/Numbers/parseInteger.hpp
@@ -4,34 +4,16 @@
 
 #pragma once
 
-#include "../Configuration.hpp"
-#include "../Polyfills/ctype.hpp"
+#include "../Polyfills/type_traits.hpp"
+#include "convertNumber.hpp"
+#include "parseNumber.hpp"
 
 namespace ARDUINOJSON_NAMESPACE {
 template <typename T>
 T parseInteger(const char *s) {
-  if (!s) return 0;  // NULL
-
-  if (*s == 't') return 1;  // "true"
-
-  T result = 0;
-  bool negative_result = false;
-
-  switch (*s) {
-    case '-':
-      negative_result = true;
-      s++;
-      break;
-    case '+':
-      s++;
-      break;
-  }
-
-  while (isdigit(*s)) {
-    result = T(result * 10 + T(*s - '0'));
-    s++;
-  }
-
-  return negative_result ? T(~result + 1) : result;
+  // try to reuse the same parameters as JsonDeserializer
+  typedef typename choose_largest<UInt, typename make_unsigned<T>::type>::type
+      TUInt;
+  return parseNumber<Float, TUInt>(s).template as<T>();
 }
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Numbers/parseNumber.hpp b/src/ArduinoJson/Numbers/parseNumber.hpp
new file mode 100644
index 00000000..35fb3468
--- /dev/null
+++ b/src/ArduinoJson/Numbers/parseNumber.hpp
@@ -0,0 +1,147 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#pragma once
+
+#include "../Polyfills/assert.hpp"
+#include "../Polyfills/ctype.hpp"
+#include "../Polyfills/math.hpp"
+#include "../Polyfills/type_traits.hpp"
+#include "../Variant/VariantContent.hpp"
+#include "FloatTraits.hpp"
+#include "convertNumber.hpp"
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <typename TFloat, typename TUInt>
+struct ParsedNumber {
+  ParsedNumber() : uintValue(0), floatValue(0), _type(VALUE_IS_NULL) {}
+
+  ParsedNumber(TUInt value, bool is_negative)
+      : uintValue(value),
+        floatValue(TFloat(value)),
+        _type(uint8_t(is_negative ? VALUE_IS_NEGATIVE_INTEGER
+                                  : VALUE_IS_POSITIVE_INTEGER)) {}
+  ParsedNumber(TFloat value) : floatValue(value), _type(VALUE_IS_FLOAT) {}
+
+  template <typename T>
+  T as() const {
+    switch (_type) {
+      case VALUE_IS_NEGATIVE_INTEGER:
+        return convertNegativeInteger<T>(uintValue);
+      case VALUE_IS_POSITIVE_INTEGER:
+        return convertPositiveInteger<T>(uintValue);
+      case VALUE_IS_FLOAT:
+        return convertFloat<T>(floatValue);
+      default:
+        return 0;
+    }
+  }
+
+  uint8_t type() const {
+    return _type;
+  }
+
+  TUInt uintValue;
+  TFloat floatValue;
+  uint8_t _type;
+};
+
+template <typename A, typename B>
+struct choose_largest : conditional<(sizeof(A) > sizeof(B)), A, B> {};
+
+template <typename TFloat, typename TUInt>
+inline ParsedNumber<TFloat, TUInt> parseNumber(const char *s) {
+  typedef FloatTraits<TFloat> traits;
+  typedef typename choose_largest<typename traits::mantissa_type, TUInt>::type
+      mantissa_t;
+  typedef typename traits::exponent_type exponent_t;
+  typedef ParsedNumber<TFloat, TUInt> return_type;
+
+  ARDUINOJSON_ASSERT(s != 0);
+
+  bool is_negative = false;
+  switch (*s) {
+    case '-':
+      is_negative = true;
+      s++;
+      break;
+    case '+':
+      s++;
+      break;
+  }
+
+  if (*s == 'n' || *s == 'N') return traits::nan();
+  if (*s == 'i' || *s == 'I')
+    return is_negative ? -traits::inf() : traits::inf();
+  if (!isdigit(*s) && *s != '.') return return_type();
+
+  mantissa_t mantissa = 0;
+  exponent_t exponent_offset = 0;
+  const mantissa_t maxUint = TUInt(-1);
+
+  while (isdigit(*s)) {
+    uint8_t digit = uint8_t(*s - '0');
+    if (mantissa > maxUint / 10) break;
+    mantissa *= 10;
+    if (mantissa > maxUint - digit) break;
+    mantissa += digit;
+    s++;
+  }
+
+  if (*s == '\0') return return_type(TUInt(mantissa), is_negative);
+
+  // avoid mantissa overflow
+  while (mantissa > traits::mantissa_max) {
+    mantissa /= 10;
+    exponent_offset++;
+  }
+
+  // remaing digits can't fit in the mantissa
+  while (isdigit(*s)) {
+    exponent_offset++;
+    s++;
+  }
+
+  if (*s == '.') {
+    s++;
+    while (isdigit(*s)) {
+      if (mantissa < traits::mantissa_max / 10) {
+        mantissa = mantissa * 10 + uint8_t(*s - '0');
+        exponent_offset--;
+      }
+      s++;
+    }
+  }
+
+  int exponent = 0;
+  if (*s == 'e' || *s == 'E') {
+    s++;
+    bool negative_exponent = false;
+    if (*s == '-') {
+      negative_exponent = true;
+      s++;
+    } else if (*s == '+') {
+      s++;
+    }
+
+    while (isdigit(*s)) {
+      exponent = exponent * 10 + (*s - '0');
+      if (exponent + exponent_offset > traits::exponent_max) {
+        if (negative_exponent)
+          return is_negative ? -0.0f : 0.0f;
+        else
+          return is_negative ? -traits::inf() : traits::inf();
+      }
+      s++;
+    }
+    if (negative_exponent) exponent = -exponent;
+  }
+  exponent += exponent_offset;
+
+  TFloat result = traits::make_float(static_cast<TFloat>(mantissa), exponent);
+
+  return is_negative ? -result : result;
+}
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/attributes.hpp b/src/ArduinoJson/Polyfills/attributes.hpp
index f0c45be7..e5beb227 100644
--- a/src/ArduinoJson/Polyfills/attributes.hpp
+++ b/src/ArduinoJson/Polyfills/attributes.hpp
@@ -33,3 +33,13 @@
 #else
 #define NOEXCEPT throw()
 #endif
+
+#if defined(__has_attribute)
+#if __has_attribute(no_sanitize)
+#define ARDUINOJSON_NO_SANITIZE(check) __attribute__((no_sanitize(check)))
+#else
+#define ARDUINOJSON_NO_SANITIZE(check)
+#endif
+#else
+#define ARDUINOJSON_NO_SANITIZE(check)
+#endif
diff --git a/src/ArduinoJson/Polyfills/limits.hpp b/src/ArduinoJson/Polyfills/limits.hpp
new file mode 100644
index 00000000..0a7b9347
--- /dev/null
+++ b/src/ArduinoJson/Polyfills/limits.hpp
@@ -0,0 +1,45 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#pragma once
+
+#include "../Polyfills/type_traits.hpp"
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4310)
+#endif
+
+namespace ARDUINOJSON_NAMESPACE {
+
+// Differs from standard because we can't use the symbols "min" and "max"
+template <typename T, typename Enable = void>
+struct numeric_limits;
+
+template <typename T>
+struct numeric_limits<T, typename enable_if<is_unsigned<T>::value>::type> {
+  static T lowest() {
+    return 0;
+  }
+  static T highest() {
+    return T(-1);
+  }
+};
+
+template <typename T>
+struct numeric_limits<
+    T, typename enable_if<is_integral<T>::value && is_signed<T>::value>::type> {
+  static T lowest() {
+    return T(T(1) << (sizeof(T) * 8 - 1));
+  }
+  static T highest() {
+    return T(~lowest());
+  }
+};
+
+}  // namespace ARDUINOJSON_NAMESPACE
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
diff --git a/src/ArduinoJson/Polyfills/type_traits.hpp b/src/ArduinoJson/Polyfills/type_traits.hpp
index b4e1a3f4..5ccc7240 100644
--- a/src/ArduinoJson/Polyfills/type_traits.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits.hpp
@@ -15,5 +15,6 @@
 #include "type_traits/is_same.hpp"
 #include "type_traits/is_signed.hpp"
 #include "type_traits/is_unsigned.hpp"
+#include "type_traits/make_unsigned.hpp"
 #include "type_traits/remove_const.hpp"
 #include "type_traits/remove_reference.hpp"
diff --git a/src/ArduinoJson/Polyfills/type_traits/make_unsigned.hpp b/src/ArduinoJson/Polyfills/type_traits/make_unsigned.hpp
new file mode 100644
index 00000000..b7fcf2f2
--- /dev/null
+++ b/src/ArduinoJson/Polyfills/type_traits/make_unsigned.hpp
@@ -0,0 +1,49 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#pragma once
+
+#include "type_identity.hpp"
+namespace ARDUINOJSON_NAMESPACE {
+
+template <typename T>
+struct make_unsigned;
+
+template <>
+struct make_unsigned<char> : type_identity<unsigned char> {};
+
+template <>
+struct make_unsigned<signed char> : type_identity<unsigned char> {};
+template <>
+struct make_unsigned<unsigned char> : type_identity<unsigned char> {};
+
+template <>
+struct make_unsigned<signed short> : type_identity<unsigned short> {};
+template <>
+struct make_unsigned<unsigned short> : type_identity<unsigned short> {};
+
+template <>
+struct make_unsigned<signed int> : type_identity<unsigned int> {};
+template <>
+struct make_unsigned<unsigned int> : type_identity<unsigned int> {};
+
+template <>
+struct make_unsigned<signed long> : type_identity<unsigned long> {};
+template <>
+struct make_unsigned<unsigned long> : type_identity<unsigned long> {};
+
+#if ARDUINOJSON_HAS_LONG_LONG
+template <>
+struct make_unsigned<signed long long> : type_identity<unsigned long long> {};
+template <>
+struct make_unsigned<unsigned long long> : type_identity<unsigned long long> {};
+#endif
+
+#if ARDUINOJSON_HAS_INT64
+template <>
+struct make_unsigned<signed __int64> : type_identity<unsigned __int64> {};
+template <>
+struct make_unsigned<unsigned __int64> : type_identity<unsigned __int64> {};
+#endif
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Polyfills/type_traits/type_identity.hpp b/src/ArduinoJson/Polyfills/type_traits/type_identity.hpp
new file mode 100644
index 00000000..c493ed7c
--- /dev/null
+++ b/src/ArduinoJson/Polyfills/type_traits/type_identity.hpp
@@ -0,0 +1,15 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#pragma once
+
+#include "integral_constant.hpp"
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <typename T>
+struct type_identity {
+  typedef T type;
+};
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Variant/VariantData.hpp b/src/ArduinoJson/Variant/VariantData.hpp
index 6e3799aa..e471c8a5 100644
--- a/src/ArduinoJson/Variant/VariantData.hpp
+++ b/src/ArduinoJson/Variant/VariantData.hpp
@@ -5,6 +5,7 @@
 #pragma once
 
 #include "../Misc/SerializedValue.hpp"
+#include "../Numbers/convertNumber.hpp"
 #include "../Polyfills/gsl/not_null.hpp"
 #include "VariantContent.hpp"
 
@@ -63,9 +64,7 @@ class VariantData {
 
   const char *asString() const;
 
-  bool asBoolean() const {
-    return asIntegral<int>() != 0;
-  }
+  bool asBoolean() const;
 
   CollectionData *asArray() {
     return isArray() ? &_content.asCollection : 0;
@@ -147,9 +146,18 @@ class VariantData {
     return (_flags & COLLECTION_MASK) != 0;
   }
 
+  template <typename T>
   bool isInteger() const {
-    return type() == VALUE_IS_POSITIVE_INTEGER ||
-           type() == VALUE_IS_NEGATIVE_INTEGER;
+    switch (type()) {
+      case VALUE_IS_POSITIVE_INTEGER:
+        return canStorePositiveInteger<T>(_content.asInteger);
+
+      case VALUE_IS_NEGATIVE_INTEGER:
+        return canStoreNegativeInteger<T>(_content.asInteger);
+
+      default:
+        return false;
+    }
   }
 
   bool isFloat() const {
@@ -225,14 +233,22 @@ class VariantData {
   template <typename T>
   void setSignedInteger(T value) {
     if (value >= 0) {
-      setType(VALUE_IS_POSITIVE_INTEGER);
-      _content.asInteger = static_cast<UInt>(value);
+      setPositiveInteger(static_cast<UInt>(value));
     } else {
-      setType(VALUE_IS_NEGATIVE_INTEGER);
-      _content.asInteger = ~static_cast<UInt>(value) + 1;
+      setNegativeInteger(~static_cast<UInt>(value) + 1);
     }
   }
 
+  void setPositiveInteger(UInt value) {
+    setType(VALUE_IS_POSITIVE_INTEGER);
+    _content.asInteger = value;
+  }
+
+  void setNegativeInteger(UInt value) {
+    setType(VALUE_IS_NEGATIVE_INTEGER);
+    _content.asInteger = value;
+  }
+
   void setLinkedString(const char *value) {
     if (value) {
       setType(VALUE_IS_LINKED_STRING);
diff --git a/src/ArduinoJson/Variant/VariantFunctions.hpp b/src/ArduinoJson/Variant/VariantFunctions.hpp
index 62de5ba6..7fd9bd6e 100644
--- a/src/ArduinoJson/Variant/VariantFunctions.hpp
+++ b/src/ArduinoJson/Variant/VariantFunctions.hpp
@@ -52,8 +52,9 @@ inline bool variantIsBoolean(const VariantData *var) {
   return var && var->isBoolean();
 }
 
+template <typename T>
 inline bool variantIsInteger(const VariantData *var) {
-  return var && var->isInteger();
+  return var && var->isInteger<T>();
 }
 
 inline bool variantIsFloat(const VariantData *var) {
diff --git a/src/ArduinoJson/Variant/VariantImpl.hpp b/src/ArduinoJson/Variant/VariantImpl.hpp
index 6dfddd7f..a925b7bb 100644
--- a/src/ArduinoJson/Variant/VariantImpl.hpp
+++ b/src/ArduinoJson/Variant/VariantImpl.hpp
@@ -5,6 +5,7 @@
 #pragma once
 
 #include "../Configuration.hpp"
+#include "../Numbers/convertNumber.hpp"
 #include "../Numbers/parseFloat.hpp"
 #include "../Numbers/parseInteger.hpp"
 #include "VariantRef.hpp"
@@ -18,19 +19,35 @@ inline T VariantData::asIntegral() const {
   switch (type()) {
     case VALUE_IS_POSITIVE_INTEGER:
     case VALUE_IS_BOOLEAN:
-      return T(_content.asInteger);
+      return convertPositiveInteger<T>(_content.asInteger);
     case VALUE_IS_NEGATIVE_INTEGER:
-      return T(~_content.asInteger + 1);
+      return convertNegativeInteger<T>(_content.asInteger);
     case VALUE_IS_LINKED_STRING:
     case VALUE_IS_OWNED_STRING:
       return parseInteger<T>(_content.asString);
     case VALUE_IS_FLOAT:
-      return T(_content.asFloat);
+      return convertFloat<T>(_content.asFloat);
     default:
       return 0;
   }
 }
 
+inline bool VariantData::asBoolean() const {
+  switch (type()) {
+    case VALUE_IS_POSITIVE_INTEGER:
+    case VALUE_IS_BOOLEAN:
+    case VALUE_IS_NEGATIVE_INTEGER:
+      return _content.asInteger != 0;
+    case VALUE_IS_FLOAT:
+      return _content.asFloat != 0;
+    case VALUE_IS_LINKED_STRING:
+    case VALUE_IS_OWNED_STRING:
+      return strcmp("true", _content.asString) == 0;
+    default:
+      return false;
+  }
+}
+
 // T = float/double
 template <typename T>
 inline T VariantData::asFloat() const {
diff --git a/src/ArduinoJson/Variant/VariantRef.hpp b/src/ArduinoJson/Variant/VariantRef.hpp
index 9a655263..5dd29315 100644
--- a/src/ArduinoJson/Variant/VariantRef.hpp
+++ b/src/ArduinoJson/Variant/VariantRef.hpp
@@ -9,8 +9,6 @@
 
 #include "../Memory/MemoryPool.hpp"
 #include "../Misc/Visitable.hpp"
-#include "../Numbers/parseFloat.hpp"
-#include "../Numbers/parseInteger.hpp"
 #include "../Operators/VariantOperators.hpp"
 #include "../Polyfills/type_traits.hpp"
 #include "VariantAs.hpp"
@@ -45,7 +43,7 @@ class VariantRefBase {
   template <typename T>
   FORCE_INLINE typename enable_if<is_integral<T>::value, bool>::type is()
       const {
-    return variantIsInteger(_data);
+    return variantIsInteger<T>(_data);
   }
   //
   // bool is<double>() const;
diff --git a/test/JsonArray/subscript.cpp b/test/JsonArray/subscript.cpp
index c9d2d381..92051cf1 100644
--- a/test/JsonArray/subscript.cpp
+++ b/test/JsonArray/subscript.cpp
@@ -22,7 +22,8 @@ TEST_CASE("JsonArray::operator[]") {
   SECTION("long long") {
     array[0] = 9223372036854775807;
     REQUIRE(9223372036854775807 == array[0].as<int64_t>());
-    REQUIRE(true == array[0].is<int>());
+    REQUIRE(true == array[0].is<int64_t>());
+    REQUIRE(false == array[0].is<int32_t>());
     REQUIRE(false == array[0].is<bool>());
   }
 #endif
diff --git a/test/JsonDeserializer/CMakeLists.txt b/test/JsonDeserializer/CMakeLists.txt
index 43da0adc..70e71db0 100644
--- a/test/JsonDeserializer/CMakeLists.txt
+++ b/test/JsonDeserializer/CMakeLists.txt
@@ -3,17 +3,18 @@
 # MIT License
 
 add_executable(JsonDeserializerTests
+	array.cpp
+	array_static.cpp
 	DeserializationError.cpp
-	deserializeJsonArray.cpp
-	deserializeJsonArrayStatic.cpp
-	deserializeJsonObject.cpp
-	deserializeJsonObjectStatic.cpp
-	deserializeJsonValue.cpp
-	deserializeJsonString.cpp
-	input_types.cpp
 	incomplete_input.cpp
+	input_types.cpp
+	number.cpp
 	invalid_input.cpp
+	misc.cpp
 	nestingLimit.cpp
+	object.cpp
+	object_static.cpp
+	string.cpp
 )
 
 target_link_libraries(JsonDeserializerTests catch)
diff --git a/test/JsonDeserializer/deserializeJsonArray.cpp b/test/JsonDeserializer/array.cpp
similarity index 100%
rename from test/JsonDeserializer/deserializeJsonArray.cpp
rename to test/JsonDeserializer/array.cpp
diff --git a/test/JsonDeserializer/deserializeJsonArrayStatic.cpp b/test/JsonDeserializer/array_static.cpp
similarity index 100%
rename from test/JsonDeserializer/deserializeJsonArrayStatic.cpp
rename to test/JsonDeserializer/array_static.cpp
diff --git a/test/JsonDeserializer/deserializeJsonValue.cpp b/test/JsonDeserializer/misc.cpp
similarity index 67%
rename from test/JsonDeserializer/deserializeJsonValue.cpp
rename to test/JsonDeserializer/misc.cpp
index 25126638..d8c6e010 100644
--- a/test/JsonDeserializer/deserializeJsonValue.cpp
+++ b/test/JsonDeserializer/misc.cpp
@@ -7,11 +7,6 @@
 
 using namespace Catch::Matchers;
 
-namespace my {
-using ARDUINOJSON_NAMESPACE::isinf;
-using ARDUINOJSON_NAMESPACE::isnan;
-}  // namespace my
-
 TEST_CASE("deserializeJson(DynamicJsonDocument&)") {
   DynamicJsonDocument doc(4096);
 
@@ -48,64 +43,6 @@ TEST_CASE("deserializeJson(DynamicJsonDocument&)") {
     }
   }
 
-  SECTION("Integers") {
-    SECTION("0") {
-      DeserializationError err = deserializeJson(doc, "0");
-      REQUIRE(err == DeserializationError::Ok);
-      REQUIRE(doc.is<int>() == true);
-      REQUIRE(doc.as<int>() == 0);
-      REQUIRE(doc.as<std::string>() == "0");  // issue #808
-    }
-
-    SECTION("Negative") {
-      DeserializationError err = deserializeJson(doc, "-42");
-
-      REQUIRE(err == DeserializationError::Ok);
-      REQUIRE(doc.is<int>());
-      REQUIRE_FALSE(doc.is<bool>());
-      REQUIRE(doc.as<int>() == -42);
-    }
-  }
-
-  SECTION("Floats") {
-    SECTION("Double") {
-      DeserializationError err = deserializeJson(doc, "-1.23e+4");
-
-      REQUIRE(err == DeserializationError::Ok);
-      REQUIRE_FALSE(doc.is<int>());
-      REQUIRE(doc.is<double>());
-      REQUIRE(doc.as<double>() == Approx(-1.23e+4));
-    }
-
-    SECTION("NaN") {
-      DeserializationError err = deserializeJson(doc, "NaN");
-      REQUIRE(err == DeserializationError::Ok);
-      REQUIRE(doc.is<float>() == true);
-      REQUIRE(my::isnan(doc.as<float>()));
-    }
-
-    SECTION("Infinity") {
-      DeserializationError err = deserializeJson(doc, "Infinity");
-      REQUIRE(err == DeserializationError::Ok);
-      REQUIRE(doc.is<float>() == true);
-      REQUIRE(my::isinf(doc.as<float>()));
-    }
-
-    SECTION("+Infinity") {
-      DeserializationError err = deserializeJson(doc, "+Infinity");
-      REQUIRE(err == DeserializationError::Ok);
-      REQUIRE(doc.is<float>() == true);
-      REQUIRE(my::isinf(doc.as<float>()));
-    }
-
-    SECTION("-Infinity") {
-      DeserializationError err = deserializeJson(doc, "-Infinity");
-      REQUIRE(err == DeserializationError::Ok);
-      REQUIRE(doc.is<float>() == true);
-      REQUIRE(my::isinf(doc.as<float>()));
-    }
-  }
-
   SECTION("Booleans") {
     SECTION("True") {
       DeserializationError err = deserializeJson(doc, "true");
diff --git a/test/JsonDeserializer/number.cpp b/test/JsonDeserializer/number.cpp
new file mode 100644
index 00000000..1a33074d
--- /dev/null
+++ b/test/JsonDeserializer/number.cpp
@@ -0,0 +1,131 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#define ARDUINOJSON_USE_LONG_LONG 0
+
+#include <ArduinoJson.h>
+#include <limits.h>
+#include <catch.hpp>
+
+namespace my {
+using ARDUINOJSON_NAMESPACE::isinf;
+using ARDUINOJSON_NAMESPACE::isnan;
+}  // namespace my
+
+TEST_CASE("deserialize an integer") {
+  DynamicJsonDocument doc(4096);
+
+  SECTION("Integer") {
+    SECTION("0") {
+      DeserializationError err = deserializeJson(doc, "0");
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<int>() == true);
+      REQUIRE(doc.as<int>() == 0);
+      REQUIRE(doc.as<std::string>() == "0");  // issue #808
+    }
+
+    SECTION("Negative") {
+      DeserializationError err = deserializeJson(doc, "-42");
+
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<int>());
+      REQUIRE_FALSE(doc.is<bool>());
+      REQUIRE(doc.as<int>() == -42);
+    }
+
+#if LONG_MAX == 2147483647
+    SECTION("LONG_MAX") {
+      DeserializationError err = deserializeJson(doc, "2147483647");
+
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<long>() == true);
+      REQUIRE(doc.as<long>() == LONG_MAX);
+    }
+
+    SECTION("LONG_MAX + 1") {
+      DeserializationError err = deserializeJson(doc, "2147483648");
+
+      CAPTURE(LONG_MIN);
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<long>() == false);
+      REQUIRE(doc.is<float>() == true);
+    }
+#endif
+
+#if LONG_MIN == -2147483648
+    SECTION("LONG_MIN") {
+      DeserializationError err = deserializeJson(doc, "-2147483648");
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<long>() == true);
+      REQUIRE(doc.as<long>() == LONG_MIN);
+    }
+
+    SECTION("LONG_MIN - 1") {
+      DeserializationError err = deserializeJson(doc, "-2147483649");
+
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<long>() == false);
+      REQUIRE(doc.is<float>() == true);
+    }
+#endif
+
+#if ULONG_MAX == 4294967295
+    SECTION("ULONG_MAX") {
+      DeserializationError err = deserializeJson(doc, "4294967295");
+
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<unsigned long>() == true);
+      REQUIRE(doc.as<unsigned long>() == ULONG_MAX);
+      REQUIRE(doc.is<long>() == false);
+    }
+
+    SECTION("ULONG_MAX + 1") {
+      DeserializationError err = deserializeJson(doc, "4294967296");
+
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<unsigned long>() == false);
+      REQUIRE(doc.is<float>() == true);
+    }
+#endif
+  }
+
+  SECTION("Floats") {
+    SECTION("Double") {
+      DeserializationError err = deserializeJson(doc, "-1.23e+4");
+
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE_FALSE(doc.is<int>());
+      REQUIRE(doc.is<double>());
+      REQUIRE(doc.as<double>() == Approx(-1.23e+4));
+    }
+
+    SECTION("NaN") {
+      DeserializationError err = deserializeJson(doc, "NaN");
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<float>() == true);
+      REQUIRE(my::isnan(doc.as<float>()));
+    }
+
+    SECTION("Infinity") {
+      DeserializationError err = deserializeJson(doc, "Infinity");
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<float>() == true);
+      REQUIRE(my::isinf(doc.as<float>()));
+    }
+
+    SECTION("+Infinity") {
+      DeserializationError err = deserializeJson(doc, "+Infinity");
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<float>() == true);
+      REQUIRE(my::isinf(doc.as<float>()));
+    }
+
+    SECTION("-Infinity") {
+      DeserializationError err = deserializeJson(doc, "-Infinity");
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<float>() == true);
+      REQUIRE(my::isinf(doc.as<float>()));
+    }
+  }
+}
diff --git a/test/JsonDeserializer/deserializeJsonObject.cpp b/test/JsonDeserializer/object.cpp
similarity index 100%
rename from test/JsonDeserializer/deserializeJsonObject.cpp
rename to test/JsonDeserializer/object.cpp
diff --git a/test/JsonDeserializer/deserializeJsonObjectStatic.cpp b/test/JsonDeserializer/object_static.cpp
similarity index 100%
rename from test/JsonDeserializer/deserializeJsonObjectStatic.cpp
rename to test/JsonDeserializer/object_static.cpp
diff --git a/test/JsonDeserializer/deserializeJsonString.cpp b/test/JsonDeserializer/string.cpp
similarity index 100%
rename from test/JsonDeserializer/deserializeJsonString.cpp
rename to test/JsonDeserializer/string.cpp
diff --git a/test/JsonVariant/CMakeLists.txt b/test/JsonVariant/CMakeLists.txt
index bee1b6ed..64a78f78 100644
--- a/test/JsonVariant/CMakeLists.txt
+++ b/test/JsonVariant/CMakeLists.txt
@@ -15,6 +15,7 @@ add_executable(JsonVariantTests
 	misc.cpp
 	nesting.cpp
 	or.cpp
+	overflow.cpp
 	remove.cpp
 	set.cpp
 	subscript.cpp
diff --git a/test/JsonVariant/as.cpp b/test/JsonVariant/as.cpp
index eeb9c514..21d2c987 100644
--- a/test/JsonVariant/as.cpp
+++ b/test/JsonVariant/as.cpp
@@ -6,6 +6,10 @@
 #include <stdint.h>
 #include <catch.hpp>
 
+namespace my {
+using ARDUINOJSON_NAMESPACE::isinf;
+}  // namespace my
+
 static const char* null = 0;
 
 TEST_CASE("JsonVariant::as()") {
@@ -94,7 +98,6 @@ TEST_CASE("JsonVariant::as()") {
   SECTION("set(\"42\")") {
     variant.set("42");
 
-    REQUIRE(variant.as<bool>());
     REQUIRE(variant.as<long>() == 42L);
   }
 
@@ -111,7 +114,6 @@ TEST_CASE("JsonVariant::as()") {
   SECTION("set(std::string(\"4.2\"))") {
     variant.set(std::string("4.2"));
 
-    REQUIRE(variant.as<bool>() == true);
     REQUIRE(variant.as<long>() == 4L);
     REQUIRE(variant.as<double>() == 4.2);
     REQUIRE(variant.as<char*>() == std::string("4.2"));
@@ -121,8 +123,31 @@ TEST_CASE("JsonVariant::as()") {
   SECTION("set(\"true\")") {
     variant.set("true");
 
-    REQUIRE(variant.as<bool>());
-    REQUIRE(variant.as<long>() == 1L);
+    REQUIRE(variant.as<bool>() == true);
+    REQUIRE(variant.as<int>() == 0);
+  }
+
+  SECTION("set(-1e300)") {
+    variant.set(-1e300);
+
+    REQUIRE(variant.as<double>() == -1e300);
+    REQUIRE(variant.as<float>() < 0);
+    REQUIRE(my::isinf(variant.as<float>()));
+  }
+
+  SECTION("set(1e300)") {
+    variant.set(1e300);
+
+    REQUIRE(variant.as<double>() == 1e300);
+    REQUIRE(variant.as<float>() > 0);
+    REQUIRE(my::isinf(variant.as<float>()));
+  }
+
+  SECTION("set(1e300)") {
+    variant.set(1e-300);
+
+    REQUIRE(variant.as<double>() == 1e-300);
+    REQUIRE(variant.as<float>() == 0);
   }
 
   SECTION("to<JsonObject>()") {
diff --git a/test/JsonVariant/overflow.cpp b/test/JsonVariant/overflow.cpp
new file mode 100644
index 00000000..8c356c9c
--- /dev/null
+++ b/test/JsonVariant/overflow.cpp
@@ -0,0 +1,72 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+template <typename TOut, typename TIn>
+void shouldBeOk(TIn value) {
+  StaticJsonDocument<1> doc;
+  JsonVariant var = doc.to<JsonVariant>();
+  var.set(value);
+  REQUIRE(var.as<TOut>() == TOut(value));
+}
+
+template <typename TOut, typename TIn>
+void shouldOverflow(TIn value) {
+  StaticJsonDocument<1> doc;
+  JsonVariant var = doc.to<JsonVariant>();
+  var.set(value);
+  REQUIRE(var.as<TOut>() == 0);
+  REQUIRE(var.is<TOut>() == false);
+}
+
+TEST_CASE("Handle integer overflow in stored integer") {
+  SECTION("int8_t") {
+    // ok
+    shouldBeOk<int8_t>(-128);
+    shouldBeOk<int8_t>(42.0);
+    shouldBeOk<int8_t>(127);
+
+    // too low
+    shouldOverflow<int8_t>(-128.1);
+    shouldOverflow<int8_t>(-129);
+
+    // too high
+    shouldOverflow<int8_t>(128);
+    shouldOverflow<int8_t>(127.1);
+  }
+
+  SECTION("int16_t") {
+    // ok
+    shouldBeOk<int16_t>(-32768);
+    shouldBeOk<int16_t>(-32767.9);
+    shouldBeOk<int16_t>(32766.9);
+    shouldBeOk<int16_t>(32767);
+
+    // too low
+    shouldOverflow<int16_t>(-32768.1);
+    shouldOverflow<int16_t>(-32769);
+
+    // too high
+    shouldOverflow<int16_t>(32767.1);
+    shouldOverflow<int16_t>(32768);
+  }
+
+  SECTION("uint8_t") {
+    // ok
+    shouldBeOk<uint8_t>(1);
+    shouldBeOk<uint8_t>(42.0);
+    shouldBeOk<uint8_t>(255);
+
+    // too low
+    shouldOverflow<uint8_t>(-1);
+    shouldOverflow<uint8_t>(-0.1);
+
+    // to high
+    shouldOverflow<uint8_t>(255.1);
+    shouldOverflow<uint8_t>(256);
+    shouldOverflow<uint8_t>(257);
+  }
+}
diff --git a/test/MsgPackDeserializer/deserializeVariant.cpp b/test/MsgPackDeserializer/deserializeVariant.cpp
index 8bcdc99a..1d8b6f08 100644
--- a/test/MsgPackDeserializer/deserializeVariant.cpp
+++ b/test/MsgPackDeserializer/deserializeVariant.cpp
@@ -16,6 +16,14 @@ static void check(const char* input, U expected) {
   REQUIRE(doc.as<T>() == expected);
 }
 
+#if ARDUINOJSON_USE_LONG_LONG == 0
+static void checkNotSupported(const char* input) {
+  DynamicJsonDocument doc(4096);
+  DeserializationError error = deserializeMsgPack(doc, input);
+  REQUIRE(error == DeserializationError::NotSupported);
+}
+#endif
+
 static void checkIsNull(const char* input) {
   DynamicJsonDocument doc(4096);
 
@@ -70,9 +78,9 @@ TEST_CASE("deserialize MsgPack value") {
     check<uint64_t>("\xCF\x12\x34\x56\x78\x9A\xBC\xDE\xF0",
                     0x123456789ABCDEF0U);
 #else
-    check<uint32_t>("\xCF\x00\x00\x00\x00\x00\x00\x00\x00", 0U);
-    check<uint32_t>("\xCF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 0xFFFFFFFF);
-    check<uint32_t>("\xCF\x12\x34\x56\x78\x9A\xBC\xDE\xF0", 0x9ABCDEF0);
+    checkNotSupported("\xCF\x00\x00\x00\x00\x00\x00\x00\x00");
+    checkNotSupported("\xCF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF");
+    checkNotSupported("\xCF\x12\x34\x56\x78\x9A\xBC\xDE\xF0");
 #endif
   }
 
@@ -95,15 +103,15 @@ TEST_CASE("deserialize MsgPack value") {
 
   SECTION("int 64") {
 #if ARDUINOJSON_USE_LONG_LONG
-    check<uint64_t>("\xD3\x00\x00\x00\x00\x00\x00\x00\x00", 0U);
-    check<uint64_t>("\xD3\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF",
-                    0xFFFFFFFFFFFFFFFFU);
-    check<uint64_t>("\xD3\x12\x34\x56\x78\x9A\xBC\xDE\xF0",
-                    0x123456789ABCDEF0U);
+    check<int64_t>("\xD3\x00\x00\x00\x00\x00\x00\x00\x00", int64_t(0U));
+    check<int64_t>("\xD3\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF",
+                   int64_t(0xFFFFFFFFFFFFFFFFU));
+    check<int64_t>("\xD3\x12\x34\x56\x78\x9A\xBC\xDE\xF0",
+                   int64_t(0x123456789ABCDEF0));
 #else
-    check<uint32_t>("\xD3\x00\x00\x00\x00\x00\x00\x00\x00", 0U);
-    check<uint32_t>("\xD3\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 0xFFFFFFFF);
-    check<uint32_t>("\xD3\x12\x34\x56\x78\x9A\xBC\xDE\xF0", 0x9ABCDEF0);
+    checkNotSupported("\xD3\x00\x00\x00\x00\x00\x00\x00\x00");
+    checkNotSupported("\xD3\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF");
+    checkNotSupported("\xD3\x12\x34\x56\x78\x9A\xBC\xDE\xF0");
 #endif
   }
 
diff --git a/test/MsgPackDeserializer/incompleteInput.cpp b/test/MsgPackDeserializer/incompleteInput.cpp
index 9c47b64e..883f7d9a 100644
--- a/test/MsgPackDeserializer/incompleteInput.cpp
+++ b/test/MsgPackDeserializer/incompleteInput.cpp
@@ -60,9 +60,11 @@ TEST_CASE("deserializeMsgPack() returns IncompleteInput") {
     checkAllSizes("\xCE\x00\x00\x00\x01", 5);
   }
 
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("uint 64") {
     checkAllSizes("\xCF\x00\x00\x00\x00\x00\x00\x00\x00", 9);
   }
+#endif
 
   SECTION("int 8") {
     checkAllSizes("\xD0\x01", 2);
@@ -76,9 +78,11 @@ TEST_CASE("deserializeMsgPack() returns IncompleteInput") {
     checkAllSizes("\xD2\x00\x00\x00\x01", 5);
   }
 
+#if ARDUINOJSON_USE_LONG_LONG
   SECTION("int 64") {
     checkAllSizes("\xD3\x00\x00\x00\x00\x00\x00\x00\x00", 9);
   }
+#endif
 
   SECTION("float 32") {
     checkAllSizes("\xCA\x40\x48\xF5\xC3", 5);
diff --git a/test/Numbers/CMakeLists.txt b/test/Numbers/CMakeLists.txt
index ef142ef7..4e39bd9b 100644
--- a/test/Numbers/CMakeLists.txt
+++ b/test/Numbers/CMakeLists.txt
@@ -3,10 +3,9 @@
 # MIT License
 
 add_executable(NumbersTests 
-	isFloat.cpp
-	isInteger.cpp
 	parseFloat.cpp
 	parseInteger.cpp
+	parseNumber.cpp
 )
 
 target_link_libraries(NumbersTests catch)
diff --git a/test/Numbers/isFloat.cpp b/test/Numbers/isFloat.cpp
deleted file mode 100644
index 7ca87b53..00000000
--- a/test/Numbers/isFloat.cpp
+++ /dev/null
@@ -1,80 +0,0 @@
-// ArduinoJson - arduinojson.org
-// Copyright Benoit Blanchon 2014-2019
-// MIT License
-
-#include <ArduinoJson/Numbers/isFloat.hpp>
-#include <catch.hpp>
-
-using namespace ARDUINOJSON_NAMESPACE;
-
-TEST_CASE("isFloat()") {
-  SECTION("Input is NULL") {
-    REQUIRE(isFloat(NULL) == false);
-  }
-
-  SECTION("Empty string") {
-    REQUIRE(isFloat("") == false);
-  }
-
-  SECTION("NoExponent") {
-    REQUIRE(isFloat("3.14") == true);
-    REQUIRE(isFloat("-3.14") == true);
-    REQUIRE(isFloat("+3.14") == true);
-  }
-
-  SECTION("IntegralPartMissing") {
-    REQUIRE(isFloat(".14") == true);
-    REQUIRE(isFloat("-.14") == true);
-    REQUIRE(isFloat("+.14") == true);
-  }
-
-  SECTION("FractionalPartMissing") {
-    REQUIRE(isFloat("3.") == true);
-    REQUIRE(isFloat("-3.e14") == true);
-    REQUIRE(isFloat("+3.e-14") == true);
-  }
-
-  SECTION("NoDot") {
-    REQUIRE(isFloat("3e14") == true);
-    REQUIRE(isFloat("3e-14") == true);
-    REQUIRE(isFloat("3e+14") == true);
-  }
-
-  SECTION("Integer") {
-    REQUIRE(isFloat("14") == true);
-    REQUIRE(isFloat("-14") == true);
-    REQUIRE(isFloat("+14") == true);
-  }
-
-  SECTION("ExponentMissing") {
-    REQUIRE(isFloat("3.14e") == false);
-    REQUIRE(isFloat("3.14e-") == false);
-    REQUIRE(isFloat("3.14e+") == false);
-  }
-
-  SECTION("JustASign") {
-    REQUIRE(isFloat("-") == false);
-    REQUIRE(isFloat("+") == false);
-  }
-
-  SECTION("Empty") {
-    REQUIRE(isFloat("") == false);
-  }
-
-  SECTION("NaN") {
-    REQUIRE(isFloat("NaN") == true);
-    REQUIRE(isFloat("n") == false);
-    REQUIRE(isFloat("N") == false);
-    REQUIRE(isFloat("nan") == false);
-    REQUIRE(isFloat("-NaN") == false);
-    REQUIRE(isFloat("+NaN") == false);
-  }
-
-  SECTION("Infinity") {
-    REQUIRE(isFloat("Infinity") == true);
-    REQUIRE(isFloat("+Infinity") == true);
-    REQUIRE(isFloat("-Infinity") == true);
-    REQUIRE(isFloat("infinity") == false);
-    REQUIRE(isFloat("Inf") == false);
-  }
-}
diff --git a/test/Numbers/isInteger.cpp b/test/Numbers/isInteger.cpp
deleted file mode 100644
index 12aabe68..00000000
--- a/test/Numbers/isInteger.cpp
+++ /dev/null
@@ -1,40 +0,0 @@
-// ArduinoJson - arduinojson.org
-// Copyright Benoit Blanchon 2014-2019
-// MIT License
-
-#include <ArduinoJson/Numbers/isInteger.hpp>
-#include <catch.hpp>
-
-using namespace ARDUINOJSON_NAMESPACE;
-
-TEST_CASE("isInteger()") {
-  SECTION("Null") {
-    REQUIRE(isInteger(NULL) == false);
-  }
-
-  SECTION("Empty string") {
-    REQUIRE(isInteger("") == false);
-  }
-
-  SECTION("FloatNotInteger") {
-    REQUIRE(isInteger("3.14") == false);
-    REQUIRE(isInteger("-3.14") == false);
-    REQUIRE(isInteger("+3.14") == false);
-  }
-
-  SECTION("Spaces") {
-    REQUIRE(isInteger("42 ") == false);
-    REQUIRE(isInteger(" 42") == false);
-  }
-
-  SECTION("Valid") {
-    REQUIRE(isInteger("42") == true);
-    REQUIRE(isInteger("-42") == true);
-    REQUIRE(isInteger("+42") == true);
-  }
-
-  SECTION("ExtraSign") {
-    REQUIRE(isInteger("--42") == false);
-    REQUIRE(isInteger("++42") == false);
-  }
-}
diff --git a/test/Numbers/parseFloat.cpp b/test/Numbers/parseFloat.cpp
index da94b5bd..4313c0d0 100644
--- a/test/Numbers/parseFloat.cpp
+++ b/test/Numbers/parseFloat.cpp
@@ -2,6 +2,8 @@
 // Copyright Benoit Blanchon 2014-2019
 // MIT License
 
+#define ARDUINOJSON_USE_DOUBLE 0
+
 #include <ArduinoJson/Numbers/parseFloat.hpp>
 #include <catch.hpp>
 
@@ -33,10 +35,6 @@ void checkInf(const char* input, bool negative) {
 }
 
 TEST_CASE("parseFloat<float>()") {
-  SECTION("Null") {
-    check<float>(NULL, 0);
-  }
-
   SECTION("Float_Short_NoExponent") {
     check<float>("3.14", 3.14f);
     check<float>("-3.14", -3.14f);
@@ -97,19 +95,13 @@ TEST_CASE("parseFloat<float>()") {
     checkInf<float>("inf", false);
     checkInf<float>("+inf", false);
     checkInf<float>("-inf", true);
-  }
 
-  SECTION("Boolean") {
-    check<float>("false", 0.0f);
-    check<float>("true", 1.0f);
+    checkInf<float>("1e300", false);
+    checkInf<float>("-1e300", true);
   }
 }
 
 TEST_CASE("parseFloat<double>()") {
-  SECTION("Null") {
-    check<double>(NULL, 0);
-  }
-
   SECTION("Short_NoExponent") {
     check<double>("3.14", 3.14);
     check<double>("-3.14", -3.14);
@@ -169,9 +161,4 @@ TEST_CASE("parseFloat<double>()") {
     checkNaN<double>("NaN");
     checkNaN<double>("nan");
   }
-
-  SECTION("Boolean") {
-    check<double>("false", 0.0);
-    check<double>("true", 1.0);
-  }
 }
diff --git a/test/Numbers/parseInteger.cpp b/test/Numbers/parseInteger.cpp
index 40d33f28..e8b3b37b 100644
--- a/test/Numbers/parseInteger.cpp
+++ b/test/Numbers/parseInteger.cpp
@@ -21,11 +21,8 @@ TEST_CASE("parseInteger<int8_t>()") {
   check<int8_t>("+127", 127);
   check<int8_t>("3.14", 3);
   check<int8_t>("x42", 0);
-  check<int8_t>("128", -128);
-  check<int8_t>("-129", 127);
-  check<int8_t>(NULL, 0);
-  check<int8_t>("true", 1);
-  check<int8_t>("false", 0);
+  check<int8_t>("128", 0);   // overflow
+  check<int8_t>("-129", 0);  // overflow
 }
 
 TEST_CASE("parseInteger<int16_t>()") {
@@ -34,11 +31,8 @@ TEST_CASE("parseInteger<int16_t>()") {
   check<int16_t>("+32767", 32767);
   check<int16_t>("3.14", 3);
   check<int16_t>("x42", 0);
-  check<int16_t>("-32769", 32767);
-  check<int16_t>("32768", -32768);
-  check<int16_t>(NULL, 0);
-  check<int16_t>("true", 1);
-  check<int16_t>("false", 0);
+  check<int16_t>("-32769", 0);  // overflow
+  check<int16_t>("32768", 0);   // overflow
 }
 
 TEST_CASE("parseInteger<int32_t>()") {
@@ -47,10 +41,8 @@ TEST_CASE("parseInteger<int32_t>()") {
   check<int32_t>("+2147483647", 2147483647);
   check<int32_t>("3.14", 3);
   check<int32_t>("x42", 0);
-  check<int32_t>("-2147483649", 2147483647);
-  check<int32_t>("2147483648", (-2147483647 - 1));
-  check<int32_t>("true", 1);
-  check<int32_t>("false", 0);
+  check<int32_t>("-2147483649", 0);  // overflow
+  check<int32_t>("2147483648", 0);   // overflow
 }
 
 TEST_CASE("parseInteger<uint8_t>()") {
@@ -59,10 +51,8 @@ TEST_CASE("parseInteger<uint8_t>()") {
   check<uint8_t>("+255", 255);
   check<uint8_t>("3.14", 3);
   check<uint8_t>("x42", 0);
-  check<uint8_t>("-1", 255);
+  check<uint8_t>("-1", 0);
   check<uint8_t>("256", 0);
-  check<uint8_t>("true", 1);
-  check<uint8_t>("false", 0);
 }
 
 TEST_CASE("parseInteger<uint16_t>()") {
@@ -72,8 +62,6 @@ TEST_CASE("parseInteger<uint16_t>()") {
   check<uint16_t>("3.14", 3);
   // check<uint16_t>(" 42", 0);
   check<uint16_t>("x42", 0);
-  check<uint16_t>("-1", 65535);
+  check<uint16_t>("-1", 0);
   check<uint16_t>("65536", 0);
-  check<uint16_t>("true", 1);
-  check<uint16_t>("false", 0);
 }
diff --git a/test/Numbers/parseNumber.cpp b/test/Numbers/parseNumber.cpp
new file mode 100644
index 00000000..19638fed
--- /dev/null
+++ b/test/Numbers/parseNumber.cpp
@@ -0,0 +1,18 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson/Numbers/parseNumber.hpp>
+#include <catch.hpp>
+
+using namespace ARDUINOJSON_NAMESPACE;
+
+TEST_CASE("Test uint32_t overflow") {
+  ParsedNumber<float, uint32_t> first =
+      parseNumber<float, uint32_t>("4294967295");
+  ParsedNumber<float, uint32_t> second =
+      parseNumber<float, uint32_t>("4294967296");
+
+  REQUIRE(first.type() == uint8_t(VALUE_IS_POSITIVE_INTEGER));
+  REQUIRE(second.type() == uint8_t(VALUE_IS_FLOAT));
+}