diff --git a/DysonNetwork.Develop/Program.cs b/DysonNetwork.Develop/Program.cs
index f735267..d9a1104 100644
--- a/DysonNetwork.Develop/Program.cs
+++ b/DysonNetwork.Develop/Program.cs
@@ -14,7 +14,7 @@ builder.ConfigureAppKestrel(builder.Configuration);
 builder.Services.AddAppServices(builder.Configuration);
 builder.Services.AddAppAuthentication();
 builder.Services.AddDysonAuth();
-builder.Services.AddPublisherService();
+builder.Services.AddSphereService();
 builder.Services.AddAccountService();
 builder.Services.AddDriveService();
 
diff --git a/DysonNetwork.Drive/Storage/FileController.cs b/DysonNetwork.Drive/Storage/FileController.cs
index 51b6c84..ac43f4a 100644
--- a/DysonNetwork.Drive/Storage/FileController.cs
+++ b/DysonNetwork.Drive/Storage/FileController.cs
@@ -187,7 +187,7 @@ public class FileController(
 
     public class MarkFileRequest
     {
-        public List<ContentSensitiveMark>? SensitiveMarks { get; set; }
+        public List<Shared.Models.ContentSensitiveMark>? SensitiveMarks { get; set; }
     }
 
     [Authorize]
@@ -298,7 +298,7 @@ public class FileController(
         public string? Description { get; set; }
         public Dictionary<string, object?>? UserMeta { get; set; }
         public Dictionary<string, object?>? FileMeta { get; set; }
-        public List<ContentSensitiveMark>? SensitiveMarks { get; set; }
+        public List<Shared.Models.ContentSensitiveMark>? SensitiveMarks { get; set; }
         public Guid PoolId { get; set; }
     }
 
diff --git a/DysonNetwork.Gateway/Program.cs b/DysonNetwork.Gateway/Program.cs
index 8350f0f..5087db8 100644
--- a/DysonNetwork.Gateway/Program.cs
+++ b/DysonNetwork.Gateway/Program.cs
@@ -122,9 +122,9 @@ var routes = specialRoutes.Concat(apiRoutes).Concat(swaggerRoutes).ToArray();
 var clusters = serviceNames.Select(serviceName => new ClusterConfig
 {
     ClusterId = serviceName,
-    HealthCheck = new()
+    HealthCheck = new HealthCheckConfig
     {
-        Active = new()
+        Active = new ActiveHealthCheckConfig
         {
             Enabled = true,
             Interval = TimeSpan.FromSeconds(10),
diff --git a/DysonNetwork.Insight/Program.cs b/DysonNetwork.Insight/Program.cs
index 279477a..083edcc 100644
--- a/DysonNetwork.Insight/Program.cs
+++ b/DysonNetwork.Insight/Program.cs
@@ -1,6 +1,7 @@
 using DysonNetwork.Insight;
 using DysonNetwork.Insight.Startup;
 using DysonNetwork.Shared.Http;
+using DysonNetwork.Shared.Registry;
 using Microsoft.EntityFrameworkCore;
 
 var builder = WebApplication.CreateBuilder(args);
@@ -10,10 +11,13 @@ builder.AddServiceDefaults();
 builder.ConfigureAppKestrel(builder.Configuration);
 
 builder.Services.AddControllers();
-builder.Services.AddAppServices(builder.Configuration);
+builder.Services.AddAppServices();
 builder.Services.AddAppAuthentication();
 builder.Services.AddAppFlushHandlers();
 builder.Services.AddAppBusinessServices();
+
+builder.Services.AddAccountService();
+builder.Services.AddSphereService();
 builder.Services.AddThinkingServices(builder.Configuration);
 
 builder.AddSwaggerManifest(
diff --git a/DysonNetwork.Insight/Startup/ServiceCollectionExtensions.cs b/DysonNetwork.Insight/Startup/ServiceCollectionExtensions.cs
index f41c761..8d3af57 100644
--- a/DysonNetwork.Insight/Startup/ServiceCollectionExtensions.cs
+++ b/DysonNetwork.Insight/Startup/ServiceCollectionExtensions.cs
@@ -10,7 +10,7 @@ namespace DysonNetwork.Insight.Startup;
 
 public static class ServiceCollectionExtensions
 {
-    public static IServiceCollection AddAppServices(this IServiceCollection services, IConfiguration configuration)
+    public static IServiceCollection AddAppServices(this IServiceCollection services)
     {
         services.AddDbContext<AppDatabase>();
         services.AddSingleton<IClock>(SystemClock.Instance);
@@ -65,8 +65,7 @@ public static class ServiceCollectionExtensions
 
     public static IServiceCollection AddThinkingServices(this IServiceCollection services, IConfiguration configuration)
     {
-        var thinkingProvider = new ThinkingProvider(configuration);
-        services.AddSingleton(thinkingProvider);
+        services.AddSingleton<ThinkingProvider>();
 
         return services;
     }
diff --git a/DysonNetwork.Insight/Thinking/ThinkingProvider.cs b/DysonNetwork.Insight/Thinking/ThinkingProvider.cs
index 4831ff8..4239b12 100644
--- a/DysonNetwork.Insight/Thinking/ThinkingProvider.cs
+++ b/DysonNetwork.Insight/Thinking/ThinkingProvider.cs
@@ -1,14 +1,34 @@
+using DysonNetwork.Shared.Proto;
 using Microsoft.SemanticKernel;
+using Microsoft.Extensions.Configuration;
+using System.Text.Json;
 
 namespace DysonNetwork.Insight.Thinking;
 
 public class ThinkingProvider
 {
-    public readonly Kernel Kernel;
-    public readonly string? ModelProviderType;
-    public readonly string? ModelDefault;
+    private readonly Kernel _kernel;
+    private readonly PostService.PostServiceClient _postClient;
+    private readonly AccountService.AccountServiceClient _accountClient;
 
-    public ThinkingProvider(IConfiguration configuration)
+    public Kernel Kernel => _kernel;
+    public string? ModelProviderType { get; private set; }
+    public string? ModelDefault { get; private set; }
+
+    public ThinkingProvider(
+        IConfiguration configuration,
+        PostService.PostServiceClient postClient,
+        AccountService.AccountServiceClient accountClient
+    )
+    {
+        _postClient = postClient;
+        _accountClient = accountClient;
+
+        _kernel = InitializeThinkingProvider(configuration);
+        InitializeHelperFunctions();
+    }
+
+    private Kernel InitializeThinkingProvider(IConfiguration configuration)
     {
         var cfg = configuration.GetSection("Thinking");
         ModelProviderType = cfg.GetValue<string>("Provider")?.ToLower();
@@ -26,23 +46,37 @@ public class ThinkingProvider
                 throw new IndexOutOfRangeException("Unknown thinking provider: " + ModelProviderType);
         }
 
-        Kernel = builder.Build();
+        return builder.Build();
+    }
 
+    private void InitializeHelperFunctions()
+    {
         // Add Solar Network tools plugin
-        Kernel.ImportPluginFromFunctions("helper_functions", [
+        _kernel.ImportPluginFromFunctions("helper_functions", [
             KernelFunctionFactory.CreateFromMethod(async (string userId) =>
             {
-                // MOCK: simulate fetching user profile
-                await Task.Delay(100);
-                return $"{{\"userId\":\"{userId}\",\"name\":\"MockUser\",\"bio\":\"Loves music and tech.\"}}";
+                var request = new GetAccountRequest { Id = userId };
+                var response = await _accountClient.GetAccountAsync(request);
+                return JsonSerializer.Serialize(response, GrpcTypeHelper.SerializerOptions);
             }, "get_user_profile", "Get a user profile from the Solar Network."),
-            KernelFunctionFactory.CreateFromMethod(async (string topic) =>
+            KernelFunctionFactory.CreateFromMethod(async (string postId) =>
             {
-                // MOCK: simulate fetching recent posts
-                await Task.Delay(200);
-                return
-                    $"[{{\"postId\":\"p1\",\"topic\":\"{topic}\",\"content\":\"Mock post content 1.\"}}, {{\"postId\":\"p2\",\"topic\":\"{topic}\",\"content\":\"Mock post content 2.\"}}]";
+                var request = new GetPostRequest { Id = postId };
+                var response = await _postClient.GetPostAsync(request);
+                return JsonSerializer.Serialize(response, GrpcTypeHelper.SerializerOptions);
+            }, "get_post", "Get a single post by ID from the Solar Network."),
+            KernelFunctionFactory.CreateFromMethod(async (string query) =>
+            {
+                var request = new SearchPostsRequest { Query = query, PageSize = 10 };
+                var response = await _postClient.SearchPostsAsync(request);
+                return JsonSerializer.Serialize(response.Posts, GrpcTypeHelper.SerializerOptions);
+            }, "search_posts", "Search posts by query from the Solar Network."),
+            KernelFunctionFactory.CreateFromMethod(async () =>
+            {
+                var request = new ListPostsRequest { PageSize = 10 };
+                var response = await _postClient.ListPostsAsync(request);
+                return JsonSerializer.Serialize(response.Posts, GrpcTypeHelper.SerializerOptions);
             }, "get_recent_posts", "Get recent posts from the Solar Network.")
         ]);
     }
-}
\ No newline at end of file
+}
diff --git a/DysonNetwork.Shared/Models/Post.cs b/DysonNetwork.Shared/Models/Post.cs
index f1014db..8c04ec6 100644
--- a/DysonNetwork.Shared/Models/Post.cs
+++ b/DysonNetwork.Shared/Models/Post.cs
@@ -1,8 +1,10 @@
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Text.Json.Serialization;
+using DysonNetwork.Shared.Proto;
 using NodaTime;
 using NpgsqlTypes;
+using Google.Protobuf.WellKnownTypes;
 
 namespace DysonNetwork.Shared.Models;
 
@@ -85,6 +87,107 @@ public class SnPost : ModelBase, IIdentifiedResource, IActivity
 
     public string ResourceIdentifier => $"post:{Id}";
 
+    public Post ToProtoValue()
+    {
+        var proto = new Post
+        {
+            Id = Id.ToString(),
+            Title = Title ?? string.Empty,
+            Description = Description ?? string.Empty,
+            Slug = Slug ?? string.Empty,
+            Visibility = (Proto.PostVisibility)((int)Visibility + 1),
+            Type = (Proto.PostType)((int)Type + 1),
+            ViewsUnique = ViewsUnique,
+            ViewsTotal = ViewsTotal,
+            Upvotes = Upvotes,
+            Downvotes = Downvotes,
+            AwardedScore = (double)AwardedScore,
+            ReactionsCount = { ReactionsCount ?? new Dictionary<string, int>() },
+            RepliesCount = RepliesCount,
+            ReactionsMade = { ReactionsMade ?? new Dictionary<string, bool>() },
+            RepliedGone = RepliedGone,
+            ForwardedGone = ForwardedGone,
+            PublisherId = PublisherId.ToString(),
+            Publisher = Publisher.ToProto(),
+            CreatedAt = Timestamp.FromDateTimeOffset(CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Timestamp.FromDateTimeOffset(UpdatedAt.ToDateTimeOffset())
+        };
+
+        if (EditedAt.HasValue)
+        {
+            proto.EditedAt = Timestamp.FromDateTimeOffset(EditedAt.Value.ToDateTimeOffset());
+        }
+
+        if (PublishedAt.HasValue)
+        {
+            proto.PublishedAt = Timestamp.FromDateTimeOffset(PublishedAt.Value.ToDateTimeOffset());
+        }
+
+        if (Content != null)
+        {
+            proto.Content = Content;
+        }
+
+        if (PinMode.HasValue)
+        {
+            proto.PinMode = (Proto.PostPinMode)((int)PinMode.Value);
+        }
+
+        if (Meta != null)
+        {
+            proto.Meta = GrpcTypeHelper.ConvertObjectToByteString(Meta);
+        }
+
+        if (SensitiveMarks != null)
+        {
+            proto.SensitiveMarks = GrpcTypeHelper.ConvertObjectToByteString(SensitiveMarks);
+        }
+
+        if (EmbedView != null)
+        {
+            proto.EmbedView = EmbedView.ToProtoValue();
+        }
+
+        if (RepliedPostId.HasValue)
+        {
+            proto.RepliedPostId = RepliedPostId.Value.ToString();
+            if (RepliedPost != null)
+            {
+                proto.RepliedPost = RepliedPost.ToProtoValue();
+            }
+        }
+
+        if (ForwardedPostId.HasValue)
+        {
+            proto.ForwardedPostId = ForwardedPostId.Value.ToString();
+            if (ForwardedPost != null)
+            {
+                proto.ForwardedPost = ForwardedPost.ToProtoValue();
+            }
+        }
+
+        if (RealmId.HasValue)
+        {
+            proto.RealmId = RealmId.Value.ToString();
+            if (Realm != null)
+            {
+                proto.Realm = Realm.ToProtoValue();
+            }
+        }
+
+        proto.Attachments.AddRange(Attachments.Select(a => a.ToProtoValue()));
+        proto.Awards.AddRange(Awards.Select(a => a.ToProto()));
+        proto.Reactions.AddRange(Reactions.Select(r => r.ToProtoValue()));
+        proto.Tags.AddRange(Tags.Select(t => t.ToProtoValue()));
+        proto.Categories.AddRange(Categories.Select(c => c.ToProtoValue()));
+        proto.FeaturedRecords.AddRange(FeaturedRecords.Select(f => f.ToProtoValue()));
+
+        if (DeletedAt.HasValue)
+            proto.DeletedAt = Timestamp.FromDateTimeOffset(DeletedAt.Value.ToDateTimeOffset());
+
+        return proto;
+    }
+
     public SnActivity ToActivity()
     {
         return new SnActivity()
@@ -108,6 +211,30 @@ public class SnPostTag : ModelBase
     [JsonIgnore] public List<SnPost> Posts { get; set; } = new List<SnPost>();
 
     [NotMapped] public int? Usage { get; set; }
+
+    public PostTag ToProtoValue()
+    {
+        return new PostTag
+        {
+            Id = Id.ToString(),
+            Slug = Slug,
+            Name = Name ?? string.Empty,
+            CreatedAt = Timestamp.FromDateTimeOffset(CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Timestamp.FromDateTimeOffset(UpdatedAt.ToDateTimeOffset())
+        };
+    }
+
+    public static SnPostTag FromProtoValue(PostTag proto)
+    {
+        return new SnPostTag
+        {
+            Id = Guid.Parse(proto.Id),
+            Slug = proto.Slug,
+            Name = proto.Name != string.Empty ? proto.Name : null,
+            CreatedAt = Instant.FromDateTimeOffset(proto.CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Instant.FromDateTimeOffset(proto.UpdatedAt.ToDateTimeOffset())
+        };
+    }
 }
 
 public class SnPostCategory : ModelBase
@@ -118,6 +245,30 @@ public class SnPostCategory : ModelBase
     [JsonIgnore] public List<SnPost> Posts { get; set; } = new List<SnPost>();
 
     [NotMapped] public int? Usage { get; set; }
+
+    public PostCategory ToProtoValue()
+    {
+        return new PostCategory
+        {
+            Id = Id.ToString(),
+            Slug = Slug,
+            Name = Name ?? string.Empty,
+            CreatedAt = Timestamp.FromDateTimeOffset(CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Timestamp.FromDateTimeOffset(UpdatedAt.ToDateTimeOffset())
+        };
+    }
+
+    public static SnPostCategory FromProtoValue(PostCategory proto)
+    {
+        return new SnPostCategory
+        {
+            Id = Guid.Parse(proto.Id),
+            Slug = proto.Slug,
+            Name = proto.Name != string.Empty ? proto.Name : null,
+            CreatedAt = Instant.FromDateTimeOffset(proto.CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Instant.FromDateTimeOffset(proto.UpdatedAt.ToDateTimeOffset())
+        };
+    }
 }
 
 public class SnPostCategorySubscription : ModelBase
@@ -150,6 +301,23 @@ public class SnPostFeaturedRecord : ModelBase
     [JsonIgnore] public SnPost Post { get; set; } = null!;
     public Instant? FeaturedAt { get; set; }
     public int SocialCredits { get; set; }
+
+    public PostFeaturedRecord ToProtoValue()
+    {
+        var proto = new PostFeaturedRecord
+        {
+            Id = Id.ToString(),
+            PostId = PostId.ToString(),
+            SocialCredits = SocialCredits,
+            CreatedAt = Timestamp.FromDateTimeOffset(CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Timestamp.FromDateTimeOffset(UpdatedAt.ToDateTimeOffset())
+        };
+        if (FeaturedAt.HasValue)
+        {
+            proto.FeaturedAt = Timestamp.FromDateTimeOffset(FeaturedAt.Value.ToDateTimeOffset());
+        }
+        return proto;
+    }
 }
 
 public enum PostReactionAttitude
@@ -169,6 +337,40 @@ public class SnPostReaction : ModelBase
     [JsonIgnore] public SnPost Post { get; set; } = null!;
     public Guid AccountId { get; set; }
     [NotMapped] public SnAccount? Account { get; set; }
+
+    public PostReaction ToProtoValue()
+    {
+        var proto = new PostReaction
+        {
+            Id = Id.ToString(),
+            Symbol = Symbol,
+            Attitude = (Proto.PostReactionAttitude)((int)Attitude + 1),
+            PostId = PostId.ToString(),
+            AccountId = AccountId.ToString(),
+            CreatedAt = Timestamp.FromDateTimeOffset(CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Timestamp.FromDateTimeOffset(UpdatedAt.ToDateTimeOffset())
+        };
+        if (Account != null)
+        {
+            proto.Account = Account.ToProtoValue();
+        }
+        return proto;
+    }
+
+    public static SnPostReaction FromProtoValue(Proto.PostReaction proto)
+    {
+        return new SnPostReaction
+        {
+            Id = Guid.Parse(proto.Id),
+            Symbol = proto.Symbol,
+            Attitude = (PostReactionAttitude)((int)proto.Attitude - 1),
+            PostId = Guid.Parse(proto.PostId),
+            AccountId = Guid.Parse(proto.AccountId),
+            Account = proto.Account != null ? SnAccount.FromProtoValue(proto.Account) : null,
+            CreatedAt = Instant.FromDateTimeOffset(proto.CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Instant.FromDateTimeOffset(proto.UpdatedAt.ToDateTimeOffset())
+        };
+    }
 }
 
 public class SnPostAward : ModelBase
@@ -181,6 +383,25 @@ public class SnPostAward : ModelBase
     public Guid PostId { get; set; }
     [JsonIgnore] public SnPost Post { get; set; } = null!;
     public Guid AccountId { get; set; }
+
+    public PostAward ToProto()
+    {
+        var proto = new PostAward
+        {
+            Id = Id.ToString(),
+            Amount = (double)Amount,
+            Attitude = (Proto.PostReactionAttitude)((int)Attitude + 1),
+            PostId = PostId.ToString(),
+            AccountId = AccountId.ToString(),
+            CreatedAt = Timestamp.FromDateTimeOffset(CreatedAt.ToDateTimeOffset()),
+            UpdatedAt = Timestamp.FromDateTimeOffset(UpdatedAt.ToDateTimeOffset())
+        };
+        if (Message != null)
+        {
+            proto.Message = Message;
+        }
+        return proto;
+    }
 }
 
 /// <summary>
@@ -193,6 +414,30 @@ public class PostEmbedView
     public string Uri { get; set; } = null!;
     public double? AspectRatio { get; set; }
     public PostEmbedViewRenderer Renderer { get; set; } = PostEmbedViewRenderer.WebView;
+
+    public Proto.PostEmbedView ToProtoValue()
+    {
+        var proto = new Proto.PostEmbedView
+        {
+            Uri = Uri,
+            Renderer = (Proto.PostEmbedViewRenderer)(int)Renderer
+        };
+        if (AspectRatio.HasValue)
+        {
+            proto.AspectRatio = AspectRatio.Value;
+        }
+        return proto;
+    }
+
+    public static PostEmbedView FromProtoValue(Proto.PostEmbedView proto)
+    {
+        return new PostEmbedView
+        {
+            Uri = proto.Uri,
+            AspectRatio = proto.HasAspectRatio ? proto.AspectRatio : null,
+            Renderer = (PostEmbedViewRenderer)((int)proto.Renderer - 1)
+        };
+    }
 }
 
 public enum PostEmbedViewRenderer
diff --git a/DysonNetwork.Shared/Proto/post.proto b/DysonNetwork.Shared/Proto/post.proto
new file mode 100644
index 0000000..dec34f7
--- /dev/null
+++ b/DysonNetwork.Shared/Proto/post.proto
@@ -0,0 +1,283 @@
+syntax = "proto3";
+
+package proto;
+
+option csharp_namespace = "DysonNetwork.Shared.Proto";
+
+import "google/protobuf/timestamp.proto";
+import "google/protobuf/wrappers.proto";
+import "google/protobuf/struct.proto";
+import "file.proto";
+import "realm.proto";
+import "publisher.proto";
+
+// Enums
+enum PostType {
+  POST_TYPE_UNSPECIFIED = 0;
+  MOMENT = 1;
+  ARTICLE = 2;
+}
+
+enum PostVisibility {
+  VISIBILITY_UNSPECIFIED = 0;
+  PUBLIC = 1;
+  FRIENDS = 2;
+  UNLISTED = 3;
+  PRIVATE = 4;
+}
+
+enum PostPinMode {
+  PIN_MODE_UNSPECIFIED = 0;
+  PUBLISHER_PAGE = 1;
+  REALM_PAGE = 2;
+  REPLY_PAGE = 3;
+}
+
+enum ContentSensitiveMark {
+  SENSITIVE_MARK_UNSPECIFIED = 0;
+  LANGUAGE = 1;
+  SEXUAL_CONTENT = 2;
+  VIOLENCE = 3;
+  PROFANITY = 4;
+  HATE_SPEECH = 5;
+  RACISM = 6;
+  ADULT_CONTENT = 7;
+  DRUG_ABUSE = 8;
+  ALCOHOL_ABUSE = 9;
+  GAMBLING = 10;
+  SELF_HARM = 11;
+  CHILD_ABUSE = 12;
+  OTHER = 13;
+}
+
+enum PostReactionAttitude {
+  ATTITUDE_UNSPECIFIED = 0;
+  POST_ATTITUDE_POSITIVE = 1;
+  POST_ATTITUDE_NEUTRAL = 2;
+  POST_ATTITUDE_NEGATIVE = 3;
+}
+
+enum PostEmbedViewRenderer {
+  RENDERER_UNSPECIFIED = 0;
+  WEBVIEW = 1;
+}
+
+// Messages
+
+message PostEmbedView {
+  string uri = 1;
+  optional double aspect_ratio = 2;
+  PostEmbedViewRenderer renderer = 3;
+}
+
+message Post {
+  string id = 1;
+  string title = 2;
+  string description = 3;
+  string slug = 4;
+  optional google.protobuf.Timestamp edited_at = 5;
+  optional google.protobuf.Timestamp published_at = 6;
+  PostVisibility visibility = 7;
+  optional string content = 8;
+
+  PostType type = 9;
+  optional PostPinMode pin_mode = 10;
+  optional bytes meta = 11; // Dictionary<string, object>
+  optional bytes sensitive_marks = 12; // List<ContentSensitiveMark>
+  optional PostEmbedView embed_view = 13;
+
+  int32 views_unique = 14;
+  int32 views_total = 15;
+  int32 upvotes = 16;
+  int32 downvotes = 17;
+  double awarded_score = 18;
+
+  // Not mapped fields: handled client-side
+  map<string, int32> reactions_count = 19; // Dictionary<string, int>
+  int32 replies_count = 20;
+  map<string, bool> reactions_made = 21; // Dictionary<string, bool>
+
+  bool replied_gone = 22;
+  bool forwarded_gone = 23;
+
+  optional string replied_post_id = 24;
+  optional Post replied_post = 25; // full if populated
+  optional string forwarded_post_id = 26;
+  optional Post forwarded_post = 27; // full if populated
+
+  optional string realm_id = 28;
+  optional Realm realm = 29; // full if populated
+
+  repeated CloudFile attachments = 30; // List<SnCloudFileReferenceObject>
+
+  string publisher_id = 31;
+  Publisher publisher = 32;
+
+  repeated PostAward awards = 33;
+  repeated PostReaction reactions = 34;
+  repeated PostTag tags = 35;
+  repeated PostCategory categories = 36;
+  repeated PostFeaturedRecord featured_records = 37;
+
+  // Added for ToActivity
+  google.protobuf.Timestamp created_at = 38;
+  google.protobuf.Timestamp updated_at = 39;
+  optional google.protobuf.Timestamp deleted_at = 40;
+}
+
+message PostTag {
+  string id = 1;
+  string slug = 2;
+  string name = 3;
+
+  google.protobuf.Timestamp created_at = 4;
+  google.protobuf.Timestamp updated_at = 5;
+}
+
+message PostCategory {
+  string id = 1;
+  string slug = 2;
+  string name = 3;
+
+  google.protobuf.Timestamp created_at = 4;
+  google.protobuf.Timestamp updated_at = 5;
+}
+
+message PostCategorySubscription {
+  string id = 1;
+  string account_id = 2;
+
+  optional string category_id = 3;
+  optional PostCategory category = 4;
+  optional string tag_id = 5;
+  optional PostTag tag = 6;
+
+  google.protobuf.Timestamp created_at = 7;
+  google.protobuf.Timestamp updated_at = 8;
+}
+
+message PostCollection {
+  string id = 1;
+  string slug = 2;
+  optional google.protobuf.StringValue name = 3;
+  optional google.protobuf.StringValue description = 4;
+
+  Publisher publisher = 5;
+  optional string publisher_id = 6; // for cases where full publisher not needed
+
+  repeated Post posts = 7;
+
+  google.protobuf.Timestamp created_at = 8;
+  google.protobuf.Timestamp updated_at = 9;
+}
+
+message PostFeaturedRecord {
+  string id = 1;
+  string post_id = 2;
+  optional google.protobuf.Timestamp featured_at = 3;
+  int32 social_credits = 4;
+
+  google.protobuf.Timestamp created_at = 5;
+  google.protobuf.Timestamp updated_at = 6;
+}
+
+message PostReaction {
+  string id = 1;
+  string symbol = 2;
+  PostReactionAttitude attitude = 3;
+
+  string post_id = 4;
+  string account_id = 5;
+  optional Account account = 6; // optional full account
+
+  google.protobuf.Timestamp created_at = 7;
+  google.protobuf.Timestamp updated_at = 8;
+}
+
+message PostAward {
+  string id = 1;
+  double amount = 2;
+  PostReactionAttitude attitude = 3;
+  optional google.protobuf.StringValue message = 4;
+
+  string post_id = 5;
+  string account_id = 6;
+
+  google.protobuf.Timestamp created_at = 7;
+  google.protobuf.Timestamp updated_at = 8;
+}
+
+// ====================================
+// Request/Response Messages
+// ====================================
+
+message GetPostRequest {
+  string id = 1;
+}
+
+message GetPostBatchRequest {
+  repeated string ids = 1;
+}
+
+message GetPostBatchResponse {
+  repeated Post posts = 1;
+}
+
+message SearchPostsRequest {
+  string query = 1;
+  string publisher_id = 2;
+  string realm_id = 3;
+  int32 page_size = 4;
+  string page_token = 5;
+  string order_by = 6;
+}
+
+message SearchPostsResponse {
+  repeated Post posts = 1;
+  string next_page_token = 2;
+  int32 total_size = 3;
+}
+
+message ListPostsRequest {
+  string publisher_id = 1;
+  string realm_id = 2;
+  int32 page_size = 3;
+  string page_token = 4;
+  string order_by = 5;
+  repeated string categories = 6;
+  repeated string tags = 7;
+  string query = 8;
+  repeated PostType types = 9;
+  optional google.protobuf.Timestamp after = 10;  // Filter posts created after this timestamp
+  optional google.protobuf.Timestamp before = 11; // Filter posts created before this timestamp
+  bool include_replies = 12; // Include reply posts
+  optional PostPinMode pinned = 13; // Filter by pinned mode (if present, null means not pinned)
+  bool only_media = 14; // Only return posts with attachments
+  bool shuffle = 15; // Random order
+}
+
+message ListPostsResponse {
+  repeated Post posts = 1;
+  string next_page_token = 2;
+  int32 total_size = 3;
+}
+
+// ====================================
+// Service Definitions
+// ====================================
+
+service PostService {
+  // Get a single post by id
+  rpc GetPost(GetPostRequest) returns (Post);
+
+  // Get multiple posts by ids
+  rpc GetPostBatch(GetPostBatchRequest) returns (GetPostBatchResponse);
+
+  // Search posts
+  rpc SearchPosts(SearchPostsRequest) returns (SearchPostsResponse);
+
+  // List posts with filters
+  rpc ListPosts(ListPostsRequest) returns (ListPostsResponse);
+}
+
+import 'account.proto';
diff --git a/DysonNetwork.Shared/Registry/ServiceInjectionHelper.cs b/DysonNetwork.Shared/Registry/ServiceInjectionHelper.cs
index 6b13a8c..0ac7628 100644
--- a/DysonNetwork.Shared/Registry/ServiceInjectionHelper.cs
+++ b/DysonNetwork.Shared/Registry/ServiceInjectionHelper.cs
@@ -59,7 +59,7 @@ public static class ServiceInjectionHelper
             .ConfigurePrimaryHttpMessageHandler(_ => new HttpClientHandler()
                 { ServerCertificateCustomValidationCallback = (_, _, _, _) => true }
             );
-        
+
         services
             .AddGrpcClient<RealmService.RealmServiceClient>(o => o.Address = new Uri("https://_grpc.pass"))
             .ConfigurePrimaryHttpMessageHandler(_ => new HttpClientHandler()
@@ -69,7 +69,7 @@ public static class ServiceInjectionHelper
 
         return services;
     }
-    
+
     public static IServiceCollection AddDriveService(this IServiceCollection services)
     {
         services.AddGrpcClient<FileService.FileServiceClient>(o => o.Address = new Uri("https://_grpc.drive"))
@@ -86,8 +86,14 @@ public static class ServiceInjectionHelper
         return services;
     }
 
-    public static IServiceCollection AddPublisherService(this IServiceCollection services)
+    public static IServiceCollection AddSphereService(this IServiceCollection services)
     {
+        services
+            .AddGrpcClient<PostService.PostServiceClient>(o => o.Address = new Uri("https://_grpc.sphere"))
+            .ConfigurePrimaryHttpMessageHandler(_ => new HttpClientHandler()
+                { ServerCertificateCustomValidationCallback = (_, _, _, _) => true }
+            );
+
         services
             .AddGrpcClient<PublisherService.PublisherServiceClient>(o => o.Address = new Uri("https://_grpc.sphere"))
             .ConfigurePrimaryHttpMessageHandler(_ => new HttpClientHandler()
@@ -107,4 +113,4 @@ public static class ServiceInjectionHelper
 
         return services;
     }
-}
+}
\ No newline at end of file
diff --git a/DysonNetwork.Sphere/Activity/ActivityService.cs b/DysonNetwork.Sphere/Activity/ActivityService.cs
index 08ab828..be922e9 100644
--- a/DysonNetwork.Sphere/Activity/ActivityService.cs
+++ b/DysonNetwork.Sphere/Activity/ActivityService.cs
@@ -12,7 +12,7 @@ namespace DysonNetwork.Sphere.Activity;
 public class ActivityService(
     AppDatabase db,
     Publisher.PublisherService pub,
-    PostService ps,
+    Post.PostService ps,
     RemoteRealmService rs,
     DiscoveryService ds,
     AccountService.AccountServiceClient accounts
diff --git a/DysonNetwork.Sphere/Post/PostController.cs b/DysonNetwork.Sphere/Post/PostController.cs
index 01e916e..7c9bc4c 100644
--- a/DysonNetwork.Sphere/Post/PostController.cs
+++ b/DysonNetwork.Sphere/Post/PostController.cs
@@ -125,7 +125,7 @@ public class PostController(
         if (realm != null)
             query = query.Where(p => p.RealmId == realm.Id);
         if (type != null)
-            query = query.Where(p => p.Type == (PostType)type);
+            query = query.Where(p => p.Type == (Shared.Models.PostType)type);
         if (categories is { Count: > 0 })
             query = query.Where(p => p.Categories.Any(c => categories.Contains(c.Slug)));
         if (tags is { Count: > 0 })
@@ -139,10 +139,10 @@ public class PostController(
         switch (pinned)
         {
             case true when realm != null:
-                query = query.Where(p => p.PinMode == PostPinMode.RealmPage);
+                query = query.Where(p => p.PinMode == Shared.Models.PostPinMode.RealmPage);
                 break;
             case true when publisher != null:
-                query = query.Where(p => p.PinMode == PostPinMode.PublisherPage);
+                query = query.Where(p => p.PinMode == Shared.Models.PostPinMode.PublisherPage);
                 break;
             case true:
                 return BadRequest(
@@ -360,7 +360,7 @@ public class PostController(
 
         var now = SystemClock.Instance.GetCurrentInstant();
         var posts = await db.Posts
-            .Where(e => e.RepliedPostId == id && e.PinMode == PostPinMode.ReplyPage)
+            .Where(e => e.RepliedPostId == id && e.PinMode == Shared.Models.PostPinMode.ReplyPage)
             .OrderByDescending(p => p.CreatedAt)
             .FilterWithVisibility(currentUser, userFriends, userPublishers)
             .ToListAsync();
@@ -425,9 +425,9 @@ public class PostController(
         [MaxLength(4096)] public string? Description { get; set; }
         [MaxLength(1024)] public string? Slug { get; set; }
         public string? Content { get; set; }
-        public PostVisibility? Visibility { get; set; } = PostVisibility.Public;
-        public PostType? Type { get; set; }
-        public PostEmbedView? EmbedView { get; set; }
+        public Shared.Models.PostVisibility? Visibility { get; set; } = Shared.Models.PostVisibility.Public;
+        public Shared.Models.PostType? Type { get; set; }
+        public Shared.Models.PostEmbedView? EmbedView { get; set; }
         [MaxLength(16)] public List<string>? Tags { get; set; }
         [MaxLength(8)] public List<string>? Categories { get; set; }
         [MaxLength(32)] public List<string>? Attachments { get; set; }
@@ -477,9 +477,9 @@ public class PostController(
             Description = request.Description,
             Slug = request.Slug,
             Content = request.Content,
-            Visibility = request.Visibility ?? PostVisibility.Public,
+            Visibility = request.Visibility ?? Shared.Models.PostVisibility.Public,
             PublishedAt = request.PublishedAt,
-            Type = request.Type ?? PostType.Moment,
+            Type = request.Type ?? Shared.Models.PostType.Moment,
             Meta = request.Meta,
             EmbedView = request.EmbedView,
             Publisher = publisher,
@@ -565,7 +565,7 @@ public class PostController(
     public class PostReactionRequest
     {
         [MaxLength(256)] public string Symbol { get; set; } = null!;
-        public PostReactionAttitude Attitude { get; set; }
+        public Shared.Models.PostReactionAttitude Attitude { get; set; }
     }
 
     public static readonly List<string> ReactionsAllowedDefault =
@@ -638,7 +638,7 @@ public class PostController(
     public class PostAwardRequest
     {
         public decimal Amount { get; set; }
-        public PostReactionAttitude Attitude { get; set; }
+        public Shared.Models.PostReactionAttitude Attitude { get; set; }
         [MaxLength(4096)] public string? Message { get; set; }
     }
 
@@ -671,7 +671,7 @@ public class PostController(
     public async Task<ActionResult<PostAwardResponse>> AwardPost(Guid id, [FromBody] PostAwardRequest request)
     {
         if (HttpContext.Items["CurrentUser"] is not Account currentUser) return Unauthorized();
-        if (request.Attitude == PostReactionAttitude.Neutral)
+        if (request.Attitude == Shared.Models.PostReactionAttitude.Neutral)
             return BadRequest("You cannot create a neutral post award");
 
         var friendsResponse =
@@ -714,7 +714,7 @@ public class PostController(
 
     public class PostPinRequest
     {
-        [Required] public PostPinMode Mode { get; set; }
+        [Required] public Shared.Models.PostPinMode Mode { get; set; }
     }
 
     [HttpPost("{id:guid}/pin")]
@@ -734,7 +734,7 @@ public class PostController(
         if (!await pub.IsMemberWithRole(post.PublisherId, accountId, PublisherMemberRole.Editor))
             return StatusCode(403, "You are not an editor of this publisher");
 
-        if (request.Mode == PostPinMode.RealmPage && post.RealmId != null)
+        if (request.Mode == Shared.Models.PostPinMode.RealmPage && post.RealmId != null)
         {
             if (!await rs.IsMemberWithRole(post.RealmId.Value, accountId, new List<int> { RealmMemberRole.Moderator }))
                 return StatusCode(403, "You are not a moderator of this realm");
@@ -782,7 +782,7 @@ public class PostController(
         if (!await pub.IsMemberWithRole(post.PublisherId, accountId, PublisherMemberRole.Editor))
             return StatusCode(403, "You are not an editor of this publisher");
 
-        if (post is { PinMode: PostPinMode.RealmPage, RealmId: not null })
+        if (post is { PinMode: Shared.Models.PostPinMode.RealmPage, RealmId: not null })
         {
             if (!await rs.IsMemberWithRole(post.RealmId.Value, accountId, new List<int> { RealmMemberRole.Moderator }))
                 return StatusCode(403, "You are not a moderator of this realm");
diff --git a/DysonNetwork.Sphere/Post/PostService.cs b/DysonNetwork.Sphere/Post/PostService.cs
index b31868b..31c6519 100644
--- a/DysonNetwork.Sphere/Post/PostService.cs
+++ b/DysonNetwork.Sphere/Post/PostService.cs
@@ -290,7 +290,7 @@ public partial class PostService(
 
     public async Task<SnPost> PreviewPostLinkAsync(SnPost item)
     {
-        if (item.Type != PostType.Moment || string.IsNullOrEmpty(item.Content)) return item;
+        if (item.Type != Shared.Models.PostType.Moment || string.IsNullOrEmpty(item.Content)) return item;
 
         // Find all URLs in the content
         var matches = GetLinkRegex().Matches(item.Content);
@@ -420,12 +420,12 @@ public partial class PostService(
         }
     }
 
-    public async Task<SnPost> PinPostAsync(SnPost post, Account currentUser, PostPinMode pinMode)
+    public async Task<SnPost> PinPostAsync(SnPost post, Account currentUser, Shared.Models.PostPinMode pinMode)
     {
         var accountId = Guid.Parse(currentUser.Id);
         if (post.RepliedPostId != null)
         {
-            if (pinMode != PostPinMode.ReplyPage)
+            if (pinMode != Shared.Models.PostPinMode.ReplyPage)
                 throw new InvalidOperationException("Replies can only be pinned in the reply page.");
             if (post.RepliedPost == null) throw new ArgumentNullException(nameof(post.RepliedPost));
 
@@ -516,11 +516,11 @@ public partial class PostService(
 
         switch (reaction.Attitude)
         {
-            case PostReactionAttitude.Positive:
+            case Shared.Models.PostReactionAttitude.Positive:
                 if (isRemoving) post.Upvotes--;
                 else post.Upvotes++;
                 break;
-            case PostReactionAttitude.Negative:
+            case Shared.Models.PostReactionAttitude.Negative:
                 if (isRemoving) post.Downvotes--;
                 else post.Downvotes++;
                 break;
@@ -771,7 +771,7 @@ public partial class PostService(
         if (currentUser is null)
         {
             // Anonymous user can only view public posts that are published
-            return post.PublishedAt != null && now >= post.PublishedAt && post.Visibility == PostVisibility.Public;
+            return post.PublishedAt != null && now >= post.PublishedAt && post.Visibility == Shared.Models.PostVisibility.Public;
         }
 
         // Check publication status - either published or user is member
@@ -781,10 +781,10 @@ public partial class PostService(
             return false;
 
         // Check visibility
-        if (post.Visibility == PostVisibility.Private && !isMember)
+        if (post.Visibility == Shared.Models.PostVisibility.Private && !isMember)
             return false;
 
-        if (post.Visibility == PostVisibility.Friends &&
+        if (post.Visibility == Shared.Models.PostVisibility.Friends &&
             !(post.Publisher.AccountId.HasValue && userFriends.Contains(post.Publisher.AccountId.Value) || isMember))
             return false;
 
@@ -843,7 +843,7 @@ public partial class PostService(
             var periodEnd = today.InUtc().Date.AtStartOfDayInZone(DateTimeZone.Utc).ToInstant();
 
             var postsInPeriod = await db.Posts
-                .Where(e => e.Visibility == PostVisibility.Public)
+                .Where(e => e.Visibility == Shared.Models.PostVisibility.Public)
                 .Where(e => e.CreatedAt >= periodStart && e.CreatedAt < periodEnd)
                 .Select(e => e.Id)
                 .ToListAsync();
@@ -854,7 +854,7 @@ public partial class PostService(
                 .Select(e => new
                 {
                     PostId = e.Key,
-                    Score = e.Sum(r => r.Attitude == PostReactionAttitude.Positive ? 1 : -1)
+                    Score = e.Sum(r => r.Attitude == Shared.Models.PostReactionAttitude.Positive ? 1 : -1)
                 })
                 .ToDictionaryAsync(e => e.PostId, e => e.Score);
 
@@ -928,7 +928,7 @@ public partial class PostService(
         Guid postId,
         Guid accountId,
         decimal amount,
-        PostReactionAttitude attitude,
+        Shared.Models.PostReactionAttitude attitude,
         string? message
     )
     {
@@ -947,7 +947,7 @@ public partial class PostService(
         db.PostAwards.Add(award);
         await db.SaveChangesAsync();
 
-        var delta = award.Attitude == PostReactionAttitude.Positive ? amount : -amount;
+        var delta = award.Attitude == Shared.Models.PostReactionAttitude.Positive ? amount : -amount;
 
         await db.Posts.Where(p => p.Id == postId)
             .ExecuteUpdateAsync(s => s.SetProperty(p => p.AwardedScore, p => p.AwardedScore + delta));
@@ -1017,20 +1017,20 @@ public static class PostQueryExtensions
         source = isListing switch
         {
             true when currentUser is not null => source.Where(e =>
-                e.Visibility != PostVisibility.Unlisted || publishersId.Contains(e.PublisherId)),
-            true => source.Where(e => e.Visibility != PostVisibility.Unlisted),
+                e.Visibility != Shared.Models.PostVisibility.Unlisted || publishersId.Contains(e.PublisherId)),
+            true => source.Where(e => e.Visibility != Shared.Models.PostVisibility.Unlisted),
             _ => source
         };
 
         if (currentUser is null)
             return source
                 .Where(e => e.PublishedAt != null && now >= e.PublishedAt)
-                .Where(e => e.Visibility == PostVisibility.Public);
+                .Where(e => e.Visibility == Shared.Models.PostVisibility.Public);
 
         return source
             .Where(e => (e.PublishedAt != null && now >= e.PublishedAt) || publishersId.Contains(e.PublisherId))
-            .Where(e => e.Visibility != PostVisibility.Private || publishersId.Contains(e.PublisherId))
-            .Where(e => e.Visibility != PostVisibility.Friends ||
+            .Where(e => e.Visibility != Shared.Models.PostVisibility.Private || publishersId.Contains(e.PublisherId))
+            .Where(e => e.Visibility != Shared.Models.PostVisibility.Friends ||
                         (e.Publisher.AccountId != null && userFriends.Contains(e.Publisher.AccountId.Value)) ||
                         publishersId.Contains(e.PublisherId));
     }
diff --git a/DysonNetwork.Sphere/Post/PostServiceGrpc.cs b/DysonNetwork.Sphere/Post/PostServiceGrpc.cs
new file mode 100644
index 0000000..b37abbb
--- /dev/null
+++ b/DysonNetwork.Sphere/Post/PostServiceGrpc.cs
@@ -0,0 +1,252 @@
+using DysonNetwork.Shared.Proto;
+using DysonNetwork.Shared.Models;
+using Grpc.Core;
+using Microsoft.EntityFrameworkCore;
+
+namespace DysonNetwork.Sphere.Post;
+
+public class PostServiceGrpc(AppDatabase db, PostService ps) : Shared.Proto.PostService.PostServiceBase
+{
+    public override async Task<Shared.Proto.Post> GetPost(GetPostRequest request, ServerCallContext context)
+    {
+        if (!Guid.TryParse(request.Id, out var id))
+            throw new RpcException(new Status(StatusCode.InvalidArgument, "invalid post id"));
+
+        var post = await db.Posts
+            .Include(p => p.Publisher)
+            .Include(p => p.Tags)
+            .Include(p => p.Categories)
+            .Include(p => p.RepliedPost)
+            .Include(p => p.ForwardedPost)
+            .Include(p => p.FeaturedRecords)
+            .FilterWithVisibility(null, [], [])
+            .FirstOrDefaultAsync(p => p.Id == id);
+
+        if (post == null) throw new RpcException(new Status(StatusCode.NotFound, "post not found"));
+
+        post = await ps.LoadPostInfo(post);
+
+        return post.ToProtoValue();
+    }
+
+    public override async Task<GetPostBatchResponse> GetPostBatch(GetPostBatchRequest request, ServerCallContext context)
+    {
+        var ids = request.Ids
+            .Where(s => !string.IsNullOrWhiteSpace(s) && Guid.TryParse(s, out _))
+            .Select(Guid.Parse)
+            .ToList();
+
+        if (ids.Count == 0) return new GetPostBatchResponse();
+
+        var posts = await db.Posts
+            .Include(p => p.Publisher)
+            .Include(p => p.Tags)
+            .Include(p => p.Categories)
+            .Include(p => p.RepliedPost)
+            .Include(p => p.ForwardedPost)
+            .Include(p => p.FeaturedRecords)
+            .Include(p => p.Awards)
+            .Where(p => ids.Contains(p.Id))
+            .FilterWithVisibility(null, [], [])
+            .ToListAsync();
+
+        posts = await ps.LoadPostInfo(posts, null);
+
+        var resp = new GetPostBatchResponse();
+        resp.Posts.AddRange(posts.Select(p => p.ToProtoValue()));
+        return resp;
+    }
+
+    public override async Task<SearchPostsResponse> SearchPosts(SearchPostsRequest request, ServerCallContext context)
+    {
+        var query = db.Posts
+            .Include(p => p.Publisher)
+            .Include(p => p.Tags)
+            .Include(p => p.Categories)
+            .Include(p => p.RepliedPost)
+            .Include(p => p.ForwardedPost)
+            .Include(p => p.Attachments)
+            .Include(p => p.Awards)
+            .Include(p => p.Reactions)
+            .Include(p => p.FeaturedRecords)
+            .Where(p => p.DeletedAt == null) // Only active posts
+            .AsQueryable();
+
+        if (!string.IsNullOrWhiteSpace(request.Query))
+        {
+            // Simple search, assuming full-text search or title/content contains
+            query = query.Where(p =>
+                EF.Functions.ILike(p.Title, $"%{request.Query}%") ||
+                EF.Functions.ILike(p.Content, $"%{request.Query}%") ||
+                EF.Functions.ILike(p.Description, $"%{request.Query}%"));
+        }
+
+        if (!string.IsNullOrWhiteSpace(request.PublisherId) && Guid.TryParse(request.PublisherId, out var pid))
+        {
+            query = query.Where(p => p.PublisherId == pid);
+        }
+
+        if (!string.IsNullOrWhiteSpace(request.RealmId) && Guid.TryParse(request.RealmId, out var rid))
+        {
+            query = query.Where(p => p.RealmId == rid);
+        }
+
+        query = query.FilterWithVisibility(null, [], []);
+
+        var totalSize = await query.CountAsync();
+
+        // Apply pagination
+        var pageSize = request.PageSize > 0 ? request.PageSize : 20;
+        var pageToken = request.PageToken;
+        var offset = string.IsNullOrEmpty(pageToken) ? 0 : int.Parse(pageToken);
+
+        var posts = await query
+            .OrderByDescending(p => p.PublishedAt ?? p.CreatedAt)
+            .Skip(offset)
+            .Take(pageSize)
+            .ToListAsync();
+
+        posts = await ps.LoadPostInfo(posts, null, true);
+
+        var nextToken = offset + pageSize < totalSize ? (offset + pageSize).ToString() : string.Empty;
+
+        var resp = new SearchPostsResponse();
+        resp.Posts.AddRange(posts.Select(p => p.ToProtoValue()));
+        resp.NextPageToken = nextToken;
+        resp.TotalSize = totalSize;
+
+        return resp;
+    }
+
+    public override async Task<ListPostsResponse> ListPosts(ListPostsRequest request, ServerCallContext context)
+    {
+        var query = db.Posts
+            .Include(p => p.Publisher)
+            .Include(p => p.Tags)
+            .Include(p => p.Categories)
+            .Include(p => p.RepliedPost)
+            .Include(p => p.ForwardedPost)
+            .Include(p => p.Awards)
+            .Include(p => p.FeaturedRecords)
+            .Where(p => p.DeletedAt == null)
+            .AsQueryable();
+
+        if (!string.IsNullOrWhiteSpace(request.PublisherId) && Guid.TryParse(request.PublisherId, out var pid))
+        {
+            query = query.Where(p => p.PublisherId == pid);
+        }
+
+        if (!string.IsNullOrWhiteSpace(request.RealmId) && Guid.TryParse(request.RealmId, out var rid))
+        {
+            query = query.Where(p => p.RealmId == rid);
+        }
+
+        if (request.Categories.Count > 0)
+        {
+            query = query.Where(p => p.Categories.Any(c => request.Categories.Contains(c.Slug)));
+        }
+
+        if (request.Tags.Count > 0)
+        {
+            query = query.Where(p => p.Tags.Any(c => request.Tags.Contains(c.Slug)));
+        }
+
+        // TODO: Add types filtering when proto is regenerated
+        // if (request.Types.Count > 0)
+        // {
+        //     var types = request.Types.Select(t => (Shared.Models.PostType)t).Distinct();
+        //     query = query.Where(p => types.Contains(p.Type));
+        // }
+
+        if (request.OnlyMedia)
+        {
+            query = query.Where(e => e.Attachments.Count > 0);
+        }
+
+        // Pinned filtering
+        switch (request.Pinned)
+        {
+            case Shared.Proto.PostPinMode.RealmPage when !string.IsNullOrWhiteSpace(request.RealmId):
+                query = query.Where(p => p.PinMode == Shared.Models.PostPinMode.RealmPage);
+                break;
+            case Shared.Proto.PostPinMode.PublisherPage when !string.IsNullOrWhiteSpace(request.PublisherId):
+                query = query.Where(p => p.PinMode == Shared.Models.PostPinMode.PublisherPage);
+                break;
+            case Shared.Proto.PostPinMode.ReplyPage:
+                query = query.Where(p => p.PinMode == Shared.Models.PostPinMode.ReplyPage);
+                break;
+            default:
+                if (request.Pinned != null)
+                {
+                    // Specific pinned mode but conditions not met, or unknown mode
+                    query = query.Where(p => p.PinMode == (Shared.Models.PostPinMode)request.Pinned);
+                }
+                else
+                {
+                    query = query.Where(p => p.PinMode == null);
+                }
+                break;
+        }
+
+        // Include/exclude replies
+        if (request.IncludeReplies)
+        {
+            // Include both root and reply posts
+        }
+        else
+        {
+            // Exclude reply posts, only root posts
+            query = query.Where(e => e.RepliedPostId == null);
+        }
+
+        // TODO: Time range filtering when proto fields are available
+        // if (request.After != null)
+        // {
+        //     var afterTime = request.After.ToDateTimeOffset();
+        //     query = query.Where(p => (p.CreatedAt >= afterTime) || (p.PublishedAt >= afterTime));
+        // }
+
+        // if (request.Before != null)
+        // {
+        //     var beforeTime = request.Before.ToDateTimeOffset();
+        //     query = query.Where(p => (p.CreatedAt <= beforeTime) || (p.PublishedAt <= beforeTime));
+        // }
+
+        // TODO: Query text search when proto field is available
+        // if (!string.IsNullOrWhiteSpace(request.Query))
+        // {
+        //     query = query.Where(p =>
+        //         EF.Functions.ILike(p.Title, $"%{request.Query}%") ||
+        //         EF.Functions.ILike(p.Content, $"%{request.Query}%") ||
+        //         EF.Functions.ILike(p.Description, $"%{request.Query}%"));
+        // }
+
+        // Visibility filter (simplified for grpc - no user context)
+        query = query.FilterWithVisibility(null, [], []);
+
+        var totalSize = await query.CountAsync();
+
+        var pageSize = request.PageSize > 0 ? request.PageSize : 20;
+        var pageToken = request.PageToken;
+        var offset = string.IsNullOrEmpty(pageToken) ? 0 : int.Parse(pageToken);
+
+        // Ordering - TODO: Add shuffle when proto field is available
+        var orderedQuery = query.OrderByDescending(e => e.PublishedAt ?? e.CreatedAt);
+
+        var posts = await orderedQuery
+            .Skip(offset)
+            .Take(pageSize)
+            .ToListAsync();
+
+        posts = await ps.LoadPostInfo(posts, null, true);
+
+        var nextToken = offset + pageSize < totalSize ? (offset + pageSize).ToString() : string.Empty;
+
+        var resp = new ListPostsResponse();
+        resp.Posts.AddRange(posts.Select(p => p.ToProtoValue()));
+        resp.NextPageToken = nextToken;
+        resp.TotalSize = totalSize;
+
+        return resp;
+    }
+}
diff --git a/DysonNetwork.Sphere/Publisher/PublisherService.cs b/DysonNetwork.Sphere/Publisher/PublisherService.cs
index 22cb479..51fdd06 100644
--- a/DysonNetwork.Sphere/Publisher/PublisherService.cs
+++ b/DysonNetwork.Sphere/Publisher/PublisherService.cs
@@ -4,6 +4,7 @@ using DysonNetwork.Shared.Proto;
 using DysonNetwork.Shared.Registry;
 using Microsoft.EntityFrameworkCore;
 using NodaTime;
+using PublisherMemberRole = DysonNetwork.Shared.Models.PublisherMemberRole;
 using PublisherType = DysonNetwork.Shared.Models.PublisherType;
 
 namespace DysonNetwork.Sphere.Publisher;
@@ -161,7 +162,7 @@ public class PublisherService(
     {
         var publisher = new SnPublisher
         {
-            Type = Shared.Models.PublisherType.Individual,
+            Type = PublisherType.Individual,
             Name = name ?? account.Name,
             Nick = nick ?? account.Nick,
             Bio = bio ?? account.Profile.Bio,
@@ -177,7 +178,7 @@ public class PublisherService(
                 new()
                 {
                     AccountId = Guid.Parse(account.Id),
-                    Role = Shared.Models.PublisherMemberRole.Owner,
+                    Role = PublisherMemberRole.Owner,
                     JoinedAt = Instant.FromDateTimeUtc(DateTime.UtcNow)
                 }
             ]
@@ -214,7 +215,7 @@ public class PublisherService(
     }
 
     public async Task<SnPublisher> CreateOrganizationPublisher(
-        Shared.Models.SnRealm realm,
+        SnRealm realm,
         Account account,
         string? name,
         string? nick,
@@ -225,7 +226,7 @@ public class PublisherService(
     {
         var publisher = new SnPublisher
         {
-            Type = Shared.Models.PublisherType.Organizational,
+            Type = PublisherType.Organizational,
             Name = name ?? realm.Slug,
             Nick = nick ?? realm.Name,
             Bio = bio ?? realm.Description,
@@ -237,7 +238,7 @@ public class PublisherService(
                 new()
                 {
                     AccountId = Guid.Parse(account.Id),
-                    Role = Shared.Models.PublisherMemberRole.Owner,
+                    Role = PublisherMemberRole.Owner,
                     JoinedAt = Instant.FromDateTimeUtc(DateTime.UtcNow)
                 }
             }
@@ -299,10 +300,10 @@ public class PublisherService(
 
         var postsCount = await db.Posts.Where(e => e.Publisher.Id == publisher.Id).CountAsync();
         var postsUpvotes = await db.PostReactions
-            .Where(r => r.Post.Publisher.Id == publisher.Id && r.Attitude == PostReactionAttitude.Positive)
+            .Where(r => r.Post.Publisher.Id == publisher.Id && r.Attitude == Shared.Models.PostReactionAttitude.Positive)
             .CountAsync();
         var postsDownvotes = await db.PostReactions
-            .Where(r => r.Post.Publisher.Id == publisher.Id && r.Attitude == PostReactionAttitude.Negative)
+            .Where(r => r.Post.Publisher.Id == publisher.Id && r.Attitude == Shared.Models.PostReactionAttitude.Negative)
             .CountAsync();
 
         var stickerPacksId = await db.StickerPacks.Where(e => e.Publisher.Id == publisher.Id).Select(e => e.Id)
diff --git a/DysonNetwork.Sphere/Publisher/PublisherSubscriptionService.cs b/DysonNetwork.Sphere/Publisher/PublisherSubscriptionService.cs
index 636da92..bfb33ec 100644
--- a/DysonNetwork.Sphere/Publisher/PublisherSubscriptionService.cs
+++ b/DysonNetwork.Sphere/Publisher/PublisherSubscriptionService.cs
@@ -11,7 +11,7 @@ namespace DysonNetwork.Sphere.Publisher;
 
 public class PublisherSubscriptionService(
     AppDatabase db,
-    PostService ps,
+    Post.PostService ps,
     IStringLocalizer<NotificationResource> localizer,
     ICacheService cache,
     RingService.RingServiceClient pusher,
@@ -54,7 +54,7 @@ public class PublisherSubscriptionService(
     {
         if (post.RepliedPostId is not null)
             return 0;
-        if (post.Visibility != PostVisibility.Public)
+        if (post.Visibility != Shared.Models.PostVisibility.Public)
             return 0;
         
         // Create notification data
diff --git a/DysonNetwork.Sphere/Startup/ApplicationConfiguration.cs b/DysonNetwork.Sphere/Startup/ApplicationConfiguration.cs
index 121606d..45558df 100644
--- a/DysonNetwork.Sphere/Startup/ApplicationConfiguration.cs
+++ b/DysonNetwork.Sphere/Startup/ApplicationConfiguration.cs
@@ -1,5 +1,6 @@
 using DysonNetwork.Shared.Auth;
 using DysonNetwork.Shared.Http;
+using DysonNetwork.Sphere.Post;
 using DysonNetwork.Sphere.Publisher;
 
 namespace DysonNetwork.Sphere.Startup;
@@ -20,6 +21,7 @@ public static class ApplicationConfiguration
         app.MapControllers();
 
         // Map gRPC services
+        app.MapGrpcService<PostServiceGrpc>();
         app.MapGrpcService<PublisherServiceGrpc>();
 
         return app;
diff --git a/DysonNetwork.Sphere/Startup/BroadcastEventHandler.cs b/DysonNetwork.Sphere/Startup/BroadcastEventHandler.cs
index 34169c4..c0d940c 100644
--- a/DysonNetwork.Sphere/Startup/BroadcastEventHandler.cs
+++ b/DysonNetwork.Sphere/Startup/BroadcastEventHandler.cs
@@ -24,7 +24,7 @@ public class PaymentOrderAwardMeta
     [JsonPropertyName("account_id")] public Guid AccountId { get; set; }
     [JsonPropertyName("post_id")] public Guid PostId { get; set; }
     [JsonPropertyName("amount")] public string Amount { get; set; } = null!;
-    [JsonPropertyName("attitude")] public PostReactionAttitude Attitude { get; set; }
+    [JsonPropertyName("attitude")] public Shared.Models.PostReactionAttitude Attitude { get; set; }
     [JsonPropertyName("message")] public string? Message { get; set; }
 }
 
@@ -82,7 +82,7 @@ public class BroadcastEventHandler(
                             logger.LogInformation("Handling post award order: {OrderId}", evt.OrderId);
 
                             await using var scope = serviceProvider.CreateAsyncScope();
-                            var ps = scope.ServiceProvider.GetRequiredService<PostService>();
+                            var ps = scope.ServiceProvider.GetRequiredService<Post.PostService>();
 
                             var amountNum = decimal.Parse(meta.Amount);