NET 8 – Memory<byte[]> is serialized as base64

Starting with .NET 8, both Memory<byte[]> and ReadOnlyMemory<byte[]> are serialized as Base64 strings. Let’s look at a quick example:

var bar = new byte[] { 28, 70, 0 };

JsonSerializer.Serialize<Memory<byte>>(bar);
JsonSerializer.Serialize<ReadOnlyMemory<byte>>(bar);
// Output: "HEYA"
Code language: C# (cs)

In contrast, Memory<int> and the likes will continue to be serialized as JSON arrays.

JsonSerializer.Serialize<Memory<int>>(new int[] { 28, 70, 0 });
// Output: [28,70,0]
Code language: C# (cs)