diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactGuid.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactGuid.cs
new file mode 100644
index 0000000000..bef40dc4bd
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactGuid.cs
@@ -0,0 +1,251 @@
+using System.Buffers;
+using System.Buffers.Text;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+[JsonConverter(typeof(IdJsonConverter))]
+public readonly struct CompactGuid(Guid value) :
+    IComparable,
+    IComparable<CompactGuid>,
+    IEquatable<CompactGuid>,
+    ISpanParsable<CompactGuid>,
+    IUtf8SpanParsable<CompactGuid>,
+    ISpanFormattable,
+    IUtf8SpanFormattable
+{
+    private const int GuidByteSize = 16;
+    private const int IdCharMaxSize = 24;
+
+    public static readonly CompactGuid Empty = new(Guid.Empty);
+
+    public static CompactGuid Create()
+    {
+        return new CompactGuid(Guid.NewGuid());
+    }
+
+    /// <inheritdoc />
+    public static CompactGuid Parse(string s, IFormatProvider? provider = null)
+    {
+        ArgumentNullException.ThrowIfNull(s);
+        return Parse(s.AsSpan(), provider);
+    }
+
+    /// <inheritdoc />
+    public static bool TryParse([NotNullWhen(true)] string? s, IFormatProvider? provider, out CompactGuid result)
+    {
+        return TryParse(s.AsSpan(), provider, out result);
+    }
+
+    /// <inheritdoc />
+    public static CompactGuid Parse(ReadOnlySpan<char> s, IFormatProvider? provider = null)
+    {
+        if (!TryParse(s, provider, out var result))
+        {
+            throw new ArgumentException(null, nameof(s));
+        }
+
+        return result;
+    }
+
+    /// <inheritdoc />
+    public static bool TryParse(ReadOnlySpan<char> s, IFormatProvider? provider, out CompactGuid result)
+    {
+        Span<byte> charBytes = stackalloc byte[IdCharMaxSize];
+        if (!Encoding.ASCII.TryGetBytes(s, charBytes, out var charBytesLength))
+        {
+            result = default;
+            return false;
+        }
+
+        return TryParse(charBytes[..charBytesLength], provider, out result);
+    }
+
+    /// <inheritdoc />
+    public static CompactGuid Parse(ReadOnlySpan<byte> utf8Text, IFormatProvider? provider = null)
+    {
+        if (!TryParse(utf8Text, provider, out var result))
+        {
+            throw new ArgumentException(null, nameof(utf8Text));
+        }
+
+        return result;
+    }
+
+    /// <inheritdoc />
+    public static bool TryParse(ReadOnlySpan<byte> utf8Text, IFormatProvider? provider, out CompactGuid result)
+    {
+        Span<byte> valueBytes = stackalloc byte[GuidByteSize];
+        OperationStatus status = Base64.DecodeFromUtf8(utf8Text, valueBytes, out _, out int written);
+
+        if (status != OperationStatus.Done || written < GuidByteSize)
+        {
+            result = default;
+            return false;
+        }
+
+        Guid value = new(valueBytes);
+        result = new CompactGuid(value);
+        return true;
+    }
+
+    public static explicit operator Guid(CompactGuid id)
+    {
+        return id._value;
+    }
+
+    public static bool operator ==(CompactGuid id1, CompactGuid id2)
+    {
+        return id1.Equals(id2);
+    }
+
+    public static bool operator !=(CompactGuid id1, CompactGuid id2)
+    {
+        return !id1.Equals(id2);
+    }
+
+    public static bool operator <(CompactGuid id1, CompactGuid id2)
+    {
+        return id1._value < id2._value;
+    }
+
+    public static bool operator >(CompactGuid id1, CompactGuid id2)
+    {
+        return id1._value > id2._value;
+    }
+
+    public static bool operator <=(CompactGuid id1, CompactGuid id2)
+    {
+        return id1.CompareTo(id2) <= 0;
+    }
+
+    public static bool operator >=(CompactGuid id1, CompactGuid id2)
+    {
+        return id1.CompareTo(id2) >= 0;
+    }
+
+    private readonly Guid _value = value;
+
+    /// <inheritdoc />
+    public override bool Equals([NotNullWhen(true)] object? obj)
+    {
+        return base.Equals(obj);
+    }
+
+    /// <inheritdoc />
+    public bool Equals(CompactGuid other)
+    {
+        return _value.Equals(other._value);
+    }
+
+    /// <inheritdoc />
+    public int CompareTo(object? obj)
+    {
+        if (obj == null)
+        {
+            return 1;
+        }
+
+        if (obj is CompactGuid other)
+        {
+            return CompareTo(other);
+        }
+
+        throw new ArgumentException(null, nameof(obj));
+    }
+
+    /// <inheritdoc />
+    public int CompareTo(CompactGuid other)
+    {
+        return _value.CompareTo(other._value);
+    }
+
+    /// <inheritdoc />
+    public override int GetHashCode()
+    {
+        return _value.GetHashCode();
+    }
+
+    /// <inheritdoc />
+    public override string ToString()
+    {
+        Span<byte> valueBytes = stackalloc byte[GuidByteSize];
+        bool ok = _value.TryWriteBytes(valueBytes);
+        Debug.Assert(ok);
+
+        Span<byte> charBytes = stackalloc byte[IdCharMaxSize];
+        OperationStatus status = Base64.EncodeToUtf8(valueBytes, charBytes, out int consumed, out int written);
+        Debug.Assert(status == OperationStatus.Done && consumed == GuidByteSize && written <= IdCharMaxSize);
+
+        return Encoding.ASCII.GetString(charBytes[..written]);
+    }
+
+    /// <inheritdoc />
+    public string ToString(string? format, IFormatProvider? formatProvider = null)
+    {
+        return ToString();
+    }
+
+    /// <inheritdoc />
+    public bool TryFormat(Span<char> destination, out int charsWritten, ReadOnlySpan<char> format, IFormatProvider? provider = null)
+    {
+        Span<byte> charBytes = stackalloc byte[IdCharMaxSize];
+        if (!TryFormat(charBytes, out int bytesWritten, format, provider))
+        {
+            charsWritten = 0;
+            return false;
+        }
+
+        Debug.Assert(bytesWritten <= IdCharMaxSize);
+
+        charsWritten = Encoding.ASCII.GetChars(charBytes[..bytesWritten], destination);
+        Debug.Assert(charsWritten == bytesWritten);
+        return true;
+    }
+
+    /// <inheritdoc />
+    public bool TryFormat(Span<byte> utf8Destination, out int bytesWritten, ReadOnlySpan<char> format, IFormatProvider? provider = null)
+    {
+        Span<byte> valueBytes = stackalloc byte[GuidByteSize];
+        if (!_value.TryWriteBytes(valueBytes))
+        {
+            bytesWritten = 0;
+            return false;
+        }
+
+        OperationStatus status = Base64.EncodeToUtf8(valueBytes, utf8Destination, out int consumed, out bytesWritten);
+        Debug.Assert(status == OperationStatus.Done && consumed == GuidByteSize && bytesWritten <= IdCharMaxSize);
+
+        return true;
+    }
+
+    private sealed class IdJsonConverter : JsonConverter<CompactGuid>
+    {
+        public override CompactGuid Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            if (reader.TokenType != JsonTokenType.String)
+            {
+                throw new ArgumentException("String expected");
+            }
+
+            if (reader.HasValueSequence)
+            {
+                var seq = reader.ValueSequence;
+                return Parse(seq.IsSingleSegment ? seq.FirstSpan : seq.ToArray());
+            }
+
+            return Parse(reader.ValueSpan);
+        }
+
+        public override void Write(Utf8JsonWriter writer, CompactGuid value, JsonSerializerOptions options)
+        {
+            Span<byte> idBytes = stackalloc byte[IdCharMaxSize];
+            _ = value.TryFormat(idBytes, out _, ReadOnlySpan<char>.Empty);
+            writer.WriteStringValue(idBytes);
+        }
+    }
+}
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactGuidConverter.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactGuidConverter.cs
new file mode 100644
index 0000000000..6b1c6b39ee
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactGuidConverter.cs
@@ -0,0 +1,7 @@
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+public class CompactGuidConverter() : ValueConverter<CompactGuid, Guid>(
+    id => (Guid)id,
+    value => new CompactGuid(value));
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactIdentifiable.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactIdentifiable.cs
new file mode 100644
index 0000000000..fc651bebb6
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactIdentifiable.cs
@@ -0,0 +1,17 @@
+using JsonApiDotNetCore.Resources;
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+// Tip: Add [HideResourceIdTypeInOpenApi] if you're using OpenAPI with JsonApiDotNetCore.OpenApi.Swashbuckle.
+public abstract class CompactIdentifiable : Identifiable<CompactGuid>
+{
+    protected override string? GetStringId(CompactGuid value)
+    {
+        return value == CompactGuid.Empty ? null : value.ToString();
+    }
+
+    protected override CompactGuid GetTypedId(string? value)
+    {
+        return value == null ? CompactGuid.Empty : CompactGuid.Parse(value);
+    }
+}
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactIdentifiableController.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactIdentifiableController.cs
new file mode 100644
index 0000000000..235ff5bf15
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/CompactIdentifiableController.cs
@@ -0,0 +1,95 @@
+using System.ComponentModel.DataAnnotations;
+using JsonApiDotNetCore.Configuration;
+using JsonApiDotNetCore.Controllers;
+using JsonApiDotNetCore.Resources;
+using JsonApiDotNetCore.Services;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
+
+#pragma warning disable format
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+public abstract class CompactIdentifiableController<TResource>(
+    IJsonApiOptions options, IResourceGraph resourceGraph, ILoggerFactory loggerFactory, IResourceService<TResource, CompactGuid> resourceService)
+    : BaseJsonApiController<TResource, CompactGuid>(options, resourceGraph, loggerFactory, resourceService)
+    where TResource : class, IIdentifiable<CompactGuid>
+{
+    [HttpGet]
+    [HttpHead]
+    public override Task<IActionResult> GetAsync(CancellationToken cancellationToken)
+    {
+        return base.GetAsync(cancellationToken);
+    }
+
+    [HttpGet("{id}")]
+    [HttpHead("{id}")]
+    public Task<IActionResult> GetAsync([Required] string id, CancellationToken cancellationToken)
+    {
+        CompactGuid idValue = CompactGuid.Parse(id);
+        return base.GetAsync(idValue, cancellationToken);
+    }
+
+    [HttpGet("{id}/{relationshipName}")]
+    [HttpHead("{id}/{relationshipName}")]
+    public Task<IActionResult> GetSecondaryAsync([Required] string id, [Required] [PreserveEmptyString] string relationshipName,
+        CancellationToken cancellationToken)
+    {
+        CompactGuid idValue = CompactGuid.Parse(id);
+        return base.GetSecondaryAsync(idValue, relationshipName, cancellationToken);
+    }
+
+    [HttpGet("{id}/relationships/{relationshipName}")]
+    [HttpHead("{id}/relationships/{relationshipName}")]
+    public Task<IActionResult> GetRelationshipAsync([Required] string id, [Required] [PreserveEmptyString] string relationshipName,
+        CancellationToken cancellationToken)
+    {
+        CompactGuid idValue = CompactGuid.Parse(id);
+        return base.GetRelationshipAsync(idValue, relationshipName, cancellationToken);
+    }
+
+    [HttpPost]
+    public override Task<IActionResult> PostAsync([FromBody] [Required] TResource resource, CancellationToken cancellationToken)
+    {
+        return base.PostAsync(resource, cancellationToken);
+    }
+
+    [HttpPost("{id}/relationships/{relationshipName}")]
+    public Task<IActionResult> PostRelationshipAsync([Required] string id, [Required] [PreserveEmptyString] string relationshipName,
+        [FromBody] [Required] ISet<IIdentifiable> rightResourceIds, CancellationToken cancellationToken)
+    {
+        CompactGuid idValue = CompactGuid.Parse(id);
+        return base.PostRelationshipAsync(idValue, relationshipName, rightResourceIds, cancellationToken);
+    }
+
+    [HttpPatch("{id}")]
+    public Task<IActionResult> PatchAsync([Required] string id, [FromBody] [Required] TResource resource, CancellationToken cancellationToken)
+    {
+        CompactGuid idValue = CompactGuid.Parse(id);
+        return base.PatchAsync(idValue, resource, cancellationToken);
+    }
+
+    [HttpPatch("{id}/relationships/{relationshipName}")]
+    // Parameter `[Required] object? rightValue` makes Swashbuckle generate the OpenAPI request body as required. We don't actually validate ModelState, so it doesn't hurt.
+    public Task<IActionResult> PatchRelationshipAsync([Required] string id, [Required] [PreserveEmptyString] string relationshipName,
+        [FromBody] [Required] object? rightValue, CancellationToken cancellationToken)
+    {
+        CompactGuid idValue = CompactGuid.Parse(id);
+        return base.PatchRelationshipAsync(idValue, relationshipName, rightValue, cancellationToken);
+    }
+
+    [HttpDelete("{id}")]
+    public Task<IActionResult> DeleteAsync([Required] string id, CancellationToken cancellationToken)
+    {
+        CompactGuid idValue = CompactGuid.Parse(id);
+        return base.DeleteAsync(idValue, cancellationToken);
+    }
+
+    [HttpDelete("{id}/relationships/{relationshipName}")]
+    public Task<IActionResult> DeleteRelationshipAsync([Required] string id, [Required] [PreserveEmptyString] string relationshipName,
+        [FromBody] [Required] ISet<IIdentifiable> rightResourceIds, CancellationToken cancellationToken)
+    {
+        CompactGuid idValue = CompactGuid.Parse(id);
+        return base.DeleteRelationshipAsync(idValue, relationshipName, rightResourceIds, cancellationToken);
+    }
+}
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/Grant.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/Grant.cs
new file mode 100644
index 0000000000..3e7592ad37
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/Grant.cs
@@ -0,0 +1,13 @@
+using JetBrains.Annotations;
+using JsonApiDotNetCore.Controllers;
+using JsonApiDotNetCore.Resources.Annotations;
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+[UsedImplicitly(ImplicitUseTargetFlags.Members)]
+[Resource(GenerateControllerEndpoints = JsonApiEndpoints.None)]
+public sealed class Grant : CompactIdentifiable
+{
+    [Attr]
+    public string Name { get; set; } = null!;
+}
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/GrantsController.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/GrantsController.cs
new file mode 100644
index 0000000000..dde0181493
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/GrantsController.cs
@@ -0,0 +1,9 @@
+using JsonApiDotNetCore.Configuration;
+using JsonApiDotNetCore.Services;
+using Microsoft.Extensions.Logging;
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+public sealed class GrantsController(
+    IJsonApiOptions options, IResourceGraph resourceGraph, ILoggerFactory loggerFactory, IResourceService<Grant, CompactGuid> resourceService)
+    : CompactIdentifiableController<Grant>(options, resourceGraph, loggerFactory, resourceService);
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionDbContext.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionDbContext.cs
new file mode 100644
index 0000000000..8476808ef8
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionDbContext.cs
@@ -0,0 +1,19 @@
+using JetBrains.Annotations;
+using Microsoft.EntityFrameworkCore;
+using TestBuildingBlocks;
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+[UsedImplicitly(ImplicitUseTargetFlags.Members)]
+public sealed class IdCompactionDbContext(DbContextOptions<IdCompactionDbContext> options)
+    : TestableDbContext(options)
+{
+    public DbSet<Grant> Grants => Set<Grant>();
+
+    protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
+    {
+        configurationBuilder
+            .Properties<CompactGuid>()
+            .HaveConversion<CompactGuidConverter>();
+    }
+}
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionStartup.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionStartup.cs
new file mode 100644
index 0000000000..01898034cc
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionStartup.cs
@@ -0,0 +1,13 @@
+using JsonApiDotNetCore.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using TestBuildingBlocks;
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+public sealed class IdCompactionStartup : TestableStartup<IdCompactionDbContext>
+{
+    protected override void AddJsonApi(IServiceCollection services)
+    {
+        services.AddJsonApi<IdCompactionDbContext>(ConfigureJsonApiOptions, resources: builder => builder.Remove<CompactIdentifiable>());
+    }
+}
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionTests.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionTests.cs
new file mode 100644
index 0000000000..c515bcab91
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompactionTests.cs
@@ -0,0 +1,52 @@
+using System.Net;
+using JsonApiDotNetCore.Configuration;
+using JsonApiDotNetCore.Serialization.Objects;
+using Microsoft.Extensions.DependencyInjection;
+using TestBuildingBlocks;
+using Xunit;
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+public sealed class IdCompationTests : IClassFixture<IntegrationTestContext<IdCompactionStartup, IdCompactionDbContext>>
+{
+    private readonly IntegrationTestContext<IdCompactionStartup, IdCompactionDbContext> _testContext;
+    private readonly IdCompationFakers _fakers = new();
+
+    public IdCompationTests(IntegrationTestContext<IdCompactionStartup, IdCompactionDbContext> testContext)
+    {
+        _testContext = testContext;
+
+        testContext.UseController<GrantsController>();
+
+        var options = (JsonApiOptions)testContext.Factory.Services.GetRequiredService<IJsonApiOptions>();
+        options.UseRelativeLinks = true;
+        options.ClientIdGeneration = ClientIdGenerationMode.Forbidden;
+    }
+
+    [Fact]
+    public async Task Can_create_resource()
+    {
+        // Arrange
+        Grant grant = _fakers.Grants.GenerateOne();
+
+        var requestBody = new
+        {
+            data = new
+            {
+                type = "grants",
+                attributes = new
+                {
+                    name = grant.Name
+                }
+            }
+        };
+
+        const string route = "/grants";
+
+        // Act
+        (HttpResponseMessage httpResponse, Document responseDocument) = await _testContext.ExecutePostAsync<Document>(route, requestBody);
+
+        // Assert
+        httpResponse.ShouldHaveStatusCode(HttpStatusCode.Created);
+    }
+}
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompationFakers.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompationFakers.cs
new file mode 100644
index 0000000000..76a9c39fdd
--- /dev/null
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdCompaction/IdCompationFakers.cs
@@ -0,0 +1,16 @@
+using Bogus;
+using TestBuildingBlocks;
+
+// @formatter:wrap_chained_method_calls chop_if_long
+// @formatter:wrap_before_first_method_call true
+
+namespace JsonApiDotNetCoreTests.IntegrationTests.IdCompaction;
+
+internal sealed class IdCompationFakers
+{
+    private readonly Lazy<Faker<Grant>> _lazyGrantFaker = new(() => new Faker<Grant>()
+        .MakeDeterministic()
+        .RuleFor(grant => grant.Name, faker => faker.Company.CompanyName()));
+
+    public Faker<Grant> Grants => _lazyGrantFaker.Value;
+}