GuidSupplement

Starting with .NET 9, Guid has added functionality compliant with UUID Version 7. However, these features are not available in older .NET environments (e.g., .NET Standard 2.0), so GuidSupplement provides nearly equivalent functionality for these platforms. You can install package from NuGet/GuidSupplement.

Table of Contents

• Target Runtime
• GuidVersion7
  • Create
  • IsVersion7
  • GetTimestamp
  • GetUnixTimeSeconds
  • TimestampComparer
• GuidExtensions
  • Guid.TryWriteBytes
  • Guid.ToByteArray
  • Guid.GetVersion
  • Guid.GetVariant
• License

Target Runtime

.NET Standard 2.0, .NET Standard 2.1, .NET 8, .NET 9, .NET 10

GuidVersion7 class

Create method

Creates a Guid compliant with UUID v7. For target runtimes below .NET 9, it executes processing equivalent to the Guid.CreateVersion7 method. For .NET 9 and above, it executes the Guid.CreateVersion7 method directly.

var guid = GuidVersion7.Create();
var guid = GuidVersion7.Create(DateTimeOffset.UtcNow);

IsVersion7 method

Returns true if the Guid is compliant with UUID v7. Returns false otherwise.

var guid = GuidVersion7.Create();

if (GuidVersion7.IsVersion7(id))
{
    Console.WriteLine("Id is UUID version 7");
}

GetTimestamp method

Retrieves the timestamp. Throws an exception if the Guid is not compliant with UUID v7.

var id = GuidVersion7.Create();
DateTimeOffset timestamp = GuidVersion7.GetTimestamp(id);

GetUnixTimeSeconds method

Retrieves the timestamp as Unix epoch milliseconds. Throws an exception if the Guid is not compliant with UUID v7.

var id = GuidVersion7.Create();
long timestamp = GuidVersion7.GetUnixTimeSeconds(id);

TimestampComparer property

var ids = new List<Guid>();
ids.Add(GuidVersion7.Create(new DateTimeOffset(2025, 10, 17, 23, 49, 0, TimeSpan.Zero)));
ids.Add(GuidVersion7.Create(new DateTimeOffset(2025, 10, 17, 23, 49, 1, TimeSpan.Zero)));
ids.Add(GuidVersion7.Create(new DateTimeOffset(2025, 10, 17, 23, 49, 2, TimeSpan.Zero)));
ids.Add(GuidVersion7.Create(new DateTimeOffset(2025, 10, 17, 23, 49, 3, TimeSpan.Zero)));

var shuffled = ids.OrderBy(_ => Guid.NewGuid()).ToList();
shuffled.Sort(GuidVersion7.TimestampComparer);

GuidExtensions

Some features added in .NET 8 and .NET 9 can be used in older .NET environments.

Guid.TryWriteBytes method

var id = new Guid("00112233-4455-6677-8899-aabbccddeeff");

Span<byte> value = stackalloc byte[16];
id.TryWriteBytes(value);
// [51, 34, 17, 0, 85, 68, 119, 102, 136, 153, 170, 187, 204, 221, 238, 255]

Guid.ToByteArray(bool bigEndian) method

var id = new Guid("00112233-4455-6677-8899-aabbccddeeff");

var bytes = id.ToByteArray(false);
// [51, 34, 17, 0, 85, 68, 119, 102, 136, 153, 170, 187, 204, 221, 238, 255]

Guid.GetVersion method

Performs the same operation as the Guid.Version property.

var id = Guid.NewGuid();
var version = id.GetVersion(); // 4

var id = GuidVersion7.Create();
var version = id.GetVersion(); // 7

Guid.GetVariant method

Performs the same operation as the Guid.Variant property.

var id = Guid.NewGuid();
var variant = id.GetVariant();

var id = GuidVersion7.Create();
var variant = id.GetVariant();

License

MIT License. Some code is implemented based on dotnet/runtime, Please check the original license.