diff --git a/src/modules/Elsa.Common/Services/MemoryStore.cs b/src/modules/Elsa.Common/Services/MemoryStore.cs
index cf644eea4..e261352fe 100644
--- a/src/modules/Elsa.Common/Services/MemoryStore.cs
+++ b/src/modules/Elsa.Common/Services/MemoryStore.cs
@@ -1,21 +1,56 @@
+using System.Collections.Concurrent;
 using Elsa.Common.Entities;
 
 namespace Elsa.Common.Services;
 
+/// <summary>
+/// A simple in-memory store for entities.
+/// </summary>
+/// <typeparam name="TEntity">The type of entity to store.</typeparam>
 public class MemoryStore<TEntity>
 {
-    private IDictionary<string, TEntity> Entities { get; set; } = new Dictionary<string, TEntity>();
+    private IDictionary<string, TEntity> Entities { get; set; } = new ConcurrentDictionary<string, TEntity>();
+    
+    /// <summary>
+    /// Adds or updates an entity.
+    /// </summary>
+    /// <param name="entity">The entity to add or update.</param>
+    /// <param name="idAccessor">A function that returns the ID of the entity.</param>
     public void Save(TEntity entity, Func<TEntity, string> idAccessor) => Entities[idAccessor(entity)] = entity;
 
+    /// <summary>
+    /// Adds or updates many entities.
+    /// </summary>
+    /// <param name="entities">The entities to add or update.</param>
+    /// <param name="idAccessor">A function that returns the ID of the entity.</param>
     public void SaveMany(IEnumerable<TEntity> entities, Func<TEntity, string> idAccessor)
     {
         foreach (var entity in entities)
             Save(entity, idAccessor);
     }
 
+    /// <summary>
+    /// Finds an entity matching the specified predicate.
+    /// </summary>
+    /// <param name="predicate">A predicate to match.</param>
+    /// <returns>The matching entity or null if no match was found.</returns>
     public TEntity? Find(Func<TEntity, bool> predicate) => Entities.Values.Where(predicate).FirstOrDefault();
+    
+    /// <summary>
+    /// Finds all entities matching the specified predicate.
+    /// </summary>
+    /// <param name="predicate">A predicate to match.</param>
+    /// <returns>The matching entities.</returns>
     public IEnumerable<TEntity> FindMany(Func<TEntity, bool> predicate) => Entities.Values.Where(predicate);
     
+    /// <summary>
+    /// Finds all entities matching the specified predicate and orders them by the specified key.
+    /// </summary>
+    /// <param name="predicate">The predicate to match.</param>
+    /// <param name="orderBy">The key to order by.</param>
+    /// <param name="orderDirection">The order direction.</param>
+    /// <typeparam name="TKey">The type of the key.</typeparam>
+    /// <returns>The matching entities.</returns>
     public IEnumerable<TEntity> FindMany<TKey>(Func<TEntity, bool> predicate, Func<TEntity, TKey> orderBy, OrderDirection orderDirection = OrderDirection.Ascending)
     {
         var query = Entities.Values.Where(predicate);
@@ -30,10 +65,24 @@ public class MemoryStore<TEntity>
         return query;
     }
 
+    /// <summary>
+    /// Lists all entities.
+    /// </summary>
+    /// <returns>All entities.</returns>
     public IEnumerable<TEntity> List() => Entities.Values;
 
+    /// <summary>
+    /// Deletes an entity by ID.
+    /// </summary>
+    /// <param name="id">The ID of the entity to delete.</param>
+    /// <returns>True if the entity was deleted, otherwise false.</returns>
     public bool Delete(string id) => Entities.Remove(id);
 
+    /// <summary>
+    /// Deletes all entities matching the specified predicate.
+    /// </summary>
+    /// <param name="predicate">The predicate to match.</param>
+    /// <returns>The number of entities deleted.</returns>
     public int DeleteWhere(Func<TEntity, bool> predicate)
     {
         var query =
@@ -48,6 +97,11 @@ public class MemoryStore<TEntity>
         return entries.Count;
     }
 
+    /// <summary>
+    /// Deletes all entities matching the specified IDs.
+    /// </summary>
+    /// <param name="ids">The IDs of the entities to delete.</param>
+    /// <returns>The number of entities deleted.</returns>
     public int DeleteMany(IEnumerable<string> ids)
     {
         var count = 0;
@@ -60,6 +114,12 @@ public class MemoryStore<TEntity>
         return count;
     }
 
+    /// <summary>
+    /// Deletes the specified entities. 
+    /// </summary>
+    /// <param name="entities">The entities to delete.</param>
+    /// <param name="idAccessor">A function that returns the ID of the entity.</param>
+    /// <returns></returns>
     public int DeleteMany(IEnumerable<TEntity> entities, Func<TEntity, string> idAccessor)
     {
         var count = 0;
@@ -75,11 +135,21 @@ public class MemoryStore<TEntity>
         return count;
     }
 
+    /// <summary>
+    /// Returns a queryable of all entities.
+    /// </summary>
+    /// <param name="query">A function that returns a queryable.</param>
+    /// <returns>A queryable of all entities.</returns>
     public IEnumerable<TEntity> Query(Func<IQueryable<TEntity>, IQueryable<TEntity>> query)
     {
         var queryable = Entities.Values.AsQueryable();
         return query(queryable);
     }
 
+    /// <summary>
+    /// Returns true if any entity matches the specified predicate.
+    /// </summary>
+    /// <param name="predicate">The predicate to match.</param>
+    /// <returns>True if any entity matches the specified predicate, otherwise false.</returns>
     public bool AnyAsync(Func<TEntity, bool> predicate) => Entities.Values.Any(predicate);
 }
\ No newline at end of file