diff --git a/Ragon.Server/Sources/Project/ProjectRegistry.cs b/Ragon.Server/Sources/Project/ProjectRegistry.cs
new file mode 100644
index 0000000..6b1fb6e
--- /dev/null
+++ b/Ragon.Server/Sources/Project/ProjectRegistry.cs
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2023-2024 Eduard Kargin <kargin.eduard@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Ragon.Server.Project;
+
+public class ProjectRegistry
+{
+  private readonly Dictionary<string, RagonProject> _projectsByKey;
+  private readonly Dictionary<int, RagonProject> _projectsById;
+  private readonly int _connectionLimitPerProject;
+
+  public ProjectRegistry(int connectionLimitPerProject)
+  {
+    _projectsByKey = new Dictionary<string, RagonProject>();
+    _projectsById = new Dictionary<int, RagonProject>();
+    _connectionLimitPerProject = connectionLimitPerProject;
+  }
+
+  public bool ValidateKey(string key)
+  {
+    if (string.IsNullOrWhiteSpace(key))
+      return false;
+
+    if (key.Length < 4)
+      return false;
+
+    return true;
+  }
+
+  public RagonProject? GetOrCreateProject(string projectKey)
+  {
+    if (!_projectsByKey.TryGetValue(projectKey, out var project))
+    {
+      project = new RagonProject(projectKey);
+      _projectsByKey[projectKey] = project;
+      _projectsById[project.Id] = project;
+    }
+
+    return project;
+  }
+
+  public bool CanConnect(string projectKey)
+  {
+    if (!_projectsByKey.TryGetValue(projectKey, out var project))
+      return true;
+
+    return project.ActiveConnections < _connectionLimitPerProject;
+  }
+
+  public void RegisterConnection(int projectId)
+  {
+    if (_projectsById.TryGetValue(projectId, out var project))
+    {
+      project.IncrementConnections();
+    }
+  }
+
+  public void UnregisterConnection(int projectId)
+  {
+    if (_projectsById.TryGetValue(projectId, out var project))
+    {
+      project.DecrementConnections();
+
+      if (project.ActiveConnections <= 0)
+      {
+        _projectsByKey.Remove(project.Key);
+        _projectsById.Remove(projectId);
+      }
+    }
+  }
+
+  public RagonProject? GetProjectById(int projectId)
+  {
+    return _projectsById.TryGetValue(projectId, out var project) ? project : null;
+  }
+}
diff --git a/Ragon.Server/Sources/Project/RagonProject.cs b/Ragon.Server/Sources/Project/RagonProject.cs
new file mode 100644
index 0000000..a8cc6ca
--- /dev/null
+++ b/Ragon.Server/Sources/Project/RagonProject.cs
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2023-2024 Eduard Kargin <kargin.eduard@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Ragon.Server.Project;
+
+public class RagonProject
+{
+  private static int _idGenerator = 0;
+
+  public int Id { get; }
+  public string Key { get; }
+  public int ActiveConnections { get; private set; }
+
+  public RagonProject(string key)
+  {
+    Id = Interlocked.Increment(ref _idGenerator);
+    Key = key;
+    ActiveConnections = 0;
+  }
+
+  public void IncrementConnections()
+  {
+    ActiveConnections++;
+  }
+
+  public void DecrementConnections()
+  {
+    if (ActiveConnections > 0)
+      ActiveConnections--;
+  }
+}