diff --git a/Assets/Mirror/Core/NetworkReaderExtensions.cs b/Assets/Mirror/Core/NetworkReaderExtensions.cs
index 4493be3db..842470df9 100644
--- a/Assets/Mirror/Core/NetworkReaderExtensions.cs
+++ b/Assets/Mirror/Core/NetworkReaderExtensions.cs
@@ -33,17 +33,34 @@ public static class NetworkReaderExtensions
         public static ushort ReadUShort(this NetworkReader reader) => reader.ReadBlittable<ushort>();
         public static ushort? ReadUShortNullable(this NetworkReader reader) => reader.ReadBlittableNullable<ushort>();
 
-        public static int ReadInt(this NetworkReader reader) => reader.ReadBlittable<int>();
-        public static int? ReadIntNullable(this NetworkReader reader) => reader.ReadBlittableNullable<int>();
+        // integer bandwidth optimization: write all ints as varint!
+        // reduces bandwidth for almost all integers.
+        // increaes bandwidth for very few large integers like hashes.
+        // => very much worth it for Mirror (see Benchmarks)
+        // => very much worth it for users (they won't have to compress manually)
+        public static int ReadInt(this NetworkReader reader) => (int)Compression.DecompressVarInt(reader);
+        public static int? ReadIntNullable(this NetworkReader reader)
+        {
+            return reader.ReadBool() ? (int)Compression.DecompressVarInt(reader) : default;
+        }
 
-        public static uint ReadUInt(this NetworkReader reader) => reader.ReadBlittable<uint>();
-        public static uint? ReadUIntNullable(this NetworkReader reader) => reader.ReadBlittableNullable<uint>();
+        public static uint ReadUInt(this NetworkReader reader) => (uint)Compression.DecompressVarUInt(reader);
+        public static uint? ReadUIntNullable(this NetworkReader reader)
+        {
+            return reader.ReadBool() ? (uint)Compression.DecompressVarUInt(reader) : default;
+        }
 
-        public static long ReadLong(this NetworkReader reader) => reader.ReadBlittable<long>();
-        public static long? ReadLongNullable(this NetworkReader reader) => reader.ReadBlittableNullable<long>();
+        public static long ReadLong(this NetworkReader reader) => Compression.DecompressVarInt(reader);
+        public static long? ReadLongNullable(this NetworkReader reader)
+        {
+            return reader.ReadBool() ? Compression.DecompressVarInt(reader) : default;
+        }
 
-        public static ulong ReadULong(this NetworkReader reader) => reader.ReadBlittable<ulong>();
-        public static ulong? ReadULongNullable(this NetworkReader reader) => reader.ReadBlittableNullable<ulong>();
+        public static ulong ReadULong(this NetworkReader reader) => Compression.DecompressVarUInt(reader);
+        public static ulong? ReadULongNullable(this NetworkReader reader)
+        {
+            return reader.ReadBool() ? Compression.DecompressVarUInt(reader) : default;
+        }
 
         public static float ReadFloat(this NetworkReader reader) => reader.ReadBlittable<float>();
         public static float? ReadFloatNullable(this NetworkReader reader) => reader.ReadBlittableNullable<float>();
diff --git a/Assets/Mirror/Core/NetworkWriterExtensions.cs b/Assets/Mirror/Core/NetworkWriterExtensions.cs
index fef9f613a..251a5d3a3 100644
--- a/Assets/Mirror/Core/NetworkWriterExtensions.cs
+++ b/Assets/Mirror/Core/NetworkWriterExtensions.cs
@@ -28,17 +28,38 @@ public static class NetworkWriterExtensions
         public static void WriteUShort(this NetworkWriter writer, ushort value) => writer.WriteBlittable(value);
         public static void WriteUShortNullable(this NetworkWriter writer, ushort? value) => writer.WriteBlittableNullable(value);
 
-        public static void WriteInt(this NetworkWriter writer, int value) => writer.WriteBlittable(value);
-        public static void WriteIntNullable(this NetworkWriter writer, int? value) => writer.WriteBlittableNullable(value);
+        // integer bandwidth optimization: write all ints as varint!
+        // reduces bandwidth for almost all integers.
+        // increaes bandwidth for very few large integers like hashes.
+        // => very much worth it for Mirror (see Benchmarks)
+        // => very much worth it for users (they won't have to compress manually)
+        public static void WriteInt(this NetworkWriter writer, int value) => Compression.CompressVarInt(writer, value);
+        public static void WriteIntNullable(this NetworkWriter writer, int? value)
+        {
+            writer.WriteBool(value.HasValue);
+            if (value.HasValue) WriteInt(writer, value.Value);
+        }
 
-        public static void WriteUInt(this NetworkWriter writer, uint value) => writer.WriteBlittable(value);
-        public static void WriteUIntNullable(this NetworkWriter writer, uint? value) => writer.WriteBlittableNullable(value);
+        public static void WriteUInt(this NetworkWriter writer, uint value) => Compression.CompressVarUInt(writer, value);
+        public static void WriteUIntNullable(this NetworkWriter writer, uint? value)
+        {
+            writer.WriteBool(value.HasValue);
+            if (value.HasValue) WriteUInt(writer, value.Value);
+        }
 
-        public static void WriteLong(this NetworkWriter writer, long value)  => writer.WriteBlittable(value);
-        public static void WriteLongNullable(this NetworkWriter writer, long? value) => writer.WriteBlittableNullable(value);
+        public static void WriteLong(this NetworkWriter writer, long value) => Compression.CompressVarInt(writer, value);
+        public static void WriteLongNullable(this NetworkWriter writer, long? value)
+        {
+            writer.WriteBool(value.HasValue);
+            if (value.HasValue) WriteLong(writer, value.Value);
+        }
 
-        public static void WriteULong(this NetworkWriter writer, ulong value) => writer.WriteBlittable(value);
-        public static void WriteULongNullable(this NetworkWriter writer, ulong? value) => writer.WriteBlittableNullable(value);
+        public static void WriteULong(this NetworkWriter writer, ulong value) => Compression.CompressVarUInt(writer, value);
+        public static void WriteULongNullable(this NetworkWriter writer, ulong? value)
+        {
+            writer.WriteBool(value.HasValue);
+            if (value.HasValue) WriteULong(writer, value.Value);
+        }
 
         public static void WriteFloat(this NetworkWriter writer, float value) => writer.WriteBlittable(value);
         public static void WriteFloatNullable(this NetworkWriter writer, float? value) => writer.WriteBlittableNullable(value);
diff --git a/Assets/Mirror/Core/Tools/Compression.cs b/Assets/Mirror/Core/Tools/Compression.cs
index d04b566b1..845d16507 100644
--- a/Assets/Mirror/Core/Tools/Compression.cs
+++ b/Assets/Mirror/Core/Tools/Compression.cs
@@ -318,7 +318,6 @@ public static void CompressVarUInt(NetworkWriter writer, ulong value)
         {
             // straight forward implementation:
             // keep this for understanding & debugging.
-            /*
             if (value <= 240)
             {
                 writer.WriteByte((byte)value);
@@ -400,11 +399,12 @@ public static void CompressVarUInt(NetworkWriter writer, ulong value)
                 writer.WriteByte((byte)((value >> 48) & 0xFF));
                 writer.WriteByte((byte)((value >> 56) & 0xFF));
             }
-            */
 
+            // DISABLED: WriteInt() always calls WriteVarInt, so we can't recurse to WriteInt here
             // faster implementation writes multiple bytes at once.
             // avoids extra Space, WriteBlittable overhead.
             // VarInt is in hot path, performance matters here.
+            /*
             if (value <= 240)
             {
                 byte a = (byte)value;
@@ -474,7 +474,7 @@ public static void CompressVarUInt(NetworkWriter writer, ulong value)
             {
                 writer.WriteByte(255);
                 writer.WriteULong(value);
-            }
+            }*/
         }
 
         // zigzag encoding https://gist.github.com/mfuerstenau/ba870a29e16536fdbaba