diff --git a/src/main/java/fr/themode/minestom/Main.java b/src/main/java/fr/themode/minestom/Main.java
index b3e826684..81a9993ed 100644
--- a/src/main/java/fr/themode/minestom/Main.java
+++ b/src/main/java/fr/themode/minestom/Main.java
@@ -8,7 +8,6 @@ import fr.adamaq01.ozao.net.server.backend.tcp.TCPServer;
 import fr.themode.minestom.entity.EntityManager;
 import fr.themode.minestom.entity.Player;
 import fr.themode.minestom.instance.BlockManager;
-import fr.themode.minestom.instance.Instance;
 import fr.themode.minestom.instance.InstanceManager;
 import fr.themode.minestom.instance.demo.StoneBlock;
 import fr.themode.minestom.listener.PacketListenerManager;
@@ -30,8 +29,8 @@ public class Main {
     public static final int TICK_PER_SECOND = 1000 / TICK_MS;
 
     // Config
-    public static final int CHUNK_VIEW_DISTANCE = 10;
-    public static final int ENTITY_VIEW_DISTANCE = 10; // TODO
+    public static final int CHUNK_VIEW_DISTANCE = 5;
+    public static final int ENTITY_VIEW_DISTANCE = 2;
 
     // Networking
     private static ConnectionManager connectionManager;
@@ -68,16 +67,9 @@ public class Main {
                     Player player = connectionManager.getPlayer(packetProcessor.getPlayerConnection(connection));
                     if (player != null) {
 
-                        Instance instance = player.getInstance();
-
-
-                        if (instance != null) {
-                            instance.removeEntity(player);
-                        }
-
                         player.remove();
 
-                        connectionManager.removePlayer(packetProcessor.getPlayerConnection(connection));
+                        connectionManager.removePlayer(player.getPlayerConnection());
                     }
                     packetProcessor.removePlayerConnection(connection);
                 }
diff --git a/src/main/java/fr/themode/minestom/Viewable.java b/src/main/java/fr/themode/minestom/Viewable.java
index bb82c936e..4063e7f38 100644
--- a/src/main/java/fr/themode/minestom/Viewable.java
+++ b/src/main/java/fr/themode/minestom/Viewable.java
@@ -54,19 +54,25 @@ public interface Viewable {
 
     default void sendPacketToViewersAndSelf(ServerPacket packet) {
         if (this instanceof Player) {
-            PacketWriter.writeCallbackPacket(packet, buffer -> {
-                int size = getViewers().size();
-                buffer.getData().retain(size + 1).markReaderIndex();
-                ((Player) this).getPlayerConnection().writeUnencodedPacket(buffer);
-                buffer.getData().resetReaderIndex();
-                if (size != 0) {
-                    for (Player viewer : getViewers()) {
-                        buffer.getData().resetReaderIndex();
-                        viewer.getPlayerConnection().writeUnencodedPacket(buffer);
-                    }
-                }
-            });
+            UNSAFE_sendPacketToViewersAndSelf(packet);
+        } else {
+            sendPacketToViewers(packet);
         }
     }
 
+    private void UNSAFE_sendPacketToViewersAndSelf(ServerPacket packet) {
+        PacketWriter.writeCallbackPacket(packet, buffer -> {
+            int size = getViewers().size();
+            buffer.getData().retain(size + 1).markReaderIndex();
+            ((Player) this).getPlayerConnection().writeUnencodedPacket(buffer);
+            buffer.getData().resetReaderIndex();
+            if (size != 0) {
+                for (Player viewer : getViewers()) {
+                    buffer.getData().resetReaderIndex();
+                    viewer.getPlayerConnection().writeUnencodedPacket(buffer);
+                }
+            }
+        });
+    }
+
 }
diff --git a/src/main/java/fr/themode/minestom/chat/Chat.java b/src/main/java/fr/themode/minestom/chat/Chat.java
index 9c622ed06..3842f2a2f 100644
--- a/src/main/java/fr/themode/minestom/chat/Chat.java
+++ b/src/main/java/fr/themode/minestom/chat/Chat.java
@@ -2,7 +2,14 @@ package fr.themode.minestom.chat;
 
 public class Chat {
 
+
     public static String rawText(String text) {
         return "{\"text\": \"" + text + "\"}";
     }
+
+    /**
+     * Different types of chat message:
+     * Colored one (simplest)
+     * Colored + event (hover/click)
+     */
 }
diff --git a/src/main/java/fr/themode/minestom/entity/Entity.java b/src/main/java/fr/themode/minestom/entity/Entity.java
index 2d08a5d77..61ddc9471 100644
--- a/src/main/java/fr/themode/minestom/entity/Entity.java
+++ b/src/main/java/fr/themode/minestom/entity/Entity.java
@@ -11,9 +11,8 @@ import fr.themode.minestom.event.Event;
 import fr.themode.minestom.instance.Chunk;
 import fr.themode.minestom.instance.Instance;
 import fr.themode.minestom.net.packet.server.play.*;
-import fr.themode.minestom.utils.Position;
-import fr.themode.minestom.utils.Utils;
 import fr.themode.minestom.utils.Vector;
+import fr.themode.minestom.utils.*;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
@@ -60,7 +59,7 @@ public abstract class Entity implements Viewable, DataContainer {
     protected long velocityTime; // Reset velocity to 0 after countdown
 
     // Synchronization
-    private long synchronizationDelay = 2000; // In ms
+    private long synchronizationDelay = 1500; // In ms
     private long lastSynchronizationTime;
 
     // Metadata
@@ -107,7 +106,7 @@ public abstract class Entity implements Viewable, DataContainer {
 
     public void teleport(Position position, Runnable callback) {
         if (instance == null)
-            return;
+            throw new IllegalStateException("You need to use Entity#setInstance before teleporting an entity!");
 
         Runnable runnable = () -> {
             refreshPosition(position.getX(), position.getY(), position.getZ());
@@ -219,7 +218,7 @@ public abstract class Entity implements Viewable, DataContainer {
                 sendPositionSynchronization();
             }
 
-            this.lastUpdate = System.currentTimeMillis();
+            this.lastUpdate = time;
         }
 
         if (shouldRemove()) {
@@ -300,23 +299,31 @@ public abstract class Entity implements Viewable, DataContainer {
         return getPosition().getDistance(entity.getPosition());
     }
 
+    public Entity getVehicle() {
+        return vehicle;
+    }
+
     public void addPassenger(Entity entity) {
-        // TODO if entity already has a vehicle, leave it before?
+        if (instance == null)
+            throw new IllegalStateException("You need to set an instance using Entity#setInstance");
+        if (entity.getVehicle() != null) {
+            entity.getVehicle().removePassenger(entity);
+        }
+
         this.passengers.add(entity);
         entity.vehicle = this;
-        if (instance != null) {
-            SetPassengersPacket passengersPacket = new SetPassengersPacket();
-            passengersPacket.vehicleEntityId = getEntityId();
 
-            int[] passengers = new int[this.passengers.size()];
-            int counter = 0;
-            for (Entity passenger : this.passengers) {
-                passengers[counter++] = passenger.getEntityId();
-            }
+        sendPassengersPacket();
+    }
 
-            passengersPacket.passengersId = passengers;
-            sendPacketToViewers(passengersPacket);
-        }
+    public void removePassenger(Entity entity) {
+        if (instance == null)
+            throw new IllegalStateException("You need to set an instance using Entity#setInstance");
+        if (!passengers.contains(entity))
+            return;
+        this.passengers.remove(entity);
+        entity.vehicle = null;
+        sendPassengersPacket();
     }
 
     public boolean hasPassenger() {
@@ -327,6 +334,20 @@ public abstract class Entity implements Viewable, DataContainer {
         return Collections.unmodifiableSet(passengers);
     }
 
+    protected void sendPassengersPacket() {
+        SetPassengersPacket passengersPacket = new SetPassengersPacket();
+        passengersPacket.vehicleEntityId = getEntityId();
+
+        int[] passengers = new int[this.passengers.size()];
+        int counter = 0;
+        for (Entity passenger : this.passengers) {
+            passengers[counter++] = passenger.getEntityId();
+        }
+
+        passengersPacket.passengersId = passengers;
+        sendPacketToViewersAndSelf(passengersPacket);
+    }
+
     public void triggerStatus(byte status) {
         EntityStatusPacket statusPacket = new EntityStatusPacket();
         statusPacket.entityId = getEntityId();
@@ -373,7 +394,44 @@ public abstract class Entity implements Viewable, DataContainer {
                 if (this instanceof Player)
                     ((Player) this).onChunkChange(lastChunk, newChunk); // Refresh loaded chunk
 
-                // TODO compare with viewers and remove if too far away
+                // Refresh entity viewable list
+                long[] lastVisibleChunksEntity = ChunkUtils.getChunksInRange(new Position(16 * lastChunk.getChunkX(), 0, 16 * lastChunk.getChunkZ()), Main.ENTITY_VIEW_DISTANCE);
+                long[] updatedVisibleChunksEntity = ChunkUtils.getChunksInRange(new Position(16 * newChunk.getChunkX(), 0, 16 * newChunk.getChunkZ()), Main.ENTITY_VIEW_DISTANCE);
+
+                int[] oldChunksEntity = ArrayUtils.getDifferencesBetweenArray(lastVisibleChunksEntity, updatedVisibleChunksEntity);
+                for (int index : oldChunksEntity) {
+                    int[] chunkPos = ChunkUtils.getChunkCoord(lastVisibleChunksEntity[index]);
+                    Chunk chunk = instance.getChunk(chunkPos[0], chunkPos[1]);
+                    if (chunk == null)
+                        continue;
+                    instance.getChunkEntities(chunk).forEach(entity -> {
+                        if (entity instanceof Player) {
+                            Player player = (Player) entity;
+                            removeViewer(player);
+                            if (this instanceof Player) {
+                                player.removeViewer((Player) this);
+                            }
+                        }
+                    });
+                }
+
+                int[] newChunksEntity = ArrayUtils.getDifferencesBetweenArray(updatedVisibleChunksEntity, lastVisibleChunksEntity);
+                for (int index : newChunksEntity) {
+                    int[] chunkPos = ChunkUtils.getChunkCoord(updatedVisibleChunksEntity[index]);
+                    Chunk chunk = instance.getChunk(chunkPos[0], chunkPos[1]);
+                    if (chunk == null)
+                        continue;
+                    instance.getChunkEntities(chunk).forEach(entity -> {
+                        if (entity instanceof Player) {
+                            Player player = (Player) entity;
+                            addViewer(player);
+                            if (this instanceof Player) {
+                                player.addViewer((Player) this);
+                            }
+                        }
+                    });
+                }
+
             }
         }
     }
@@ -448,12 +506,8 @@ public abstract class Entity implements Viewable, DataContainer {
         EntityMetaDataPacket metaDataPacket = new EntityMetaDataPacket();
         metaDataPacket.entityId = getEntityId();
         metaDataPacket.data = buffer;
-        if (this instanceof Player) {
-            Player player = (Player) this;
-            player.sendPacketToViewersAndSelf(metaDataPacket);
-        } else {
-            sendPacketToViewers(metaDataPacket);
-        }
+
+        sendPacketToViewersAndSelf(metaDataPacket);
     }
 
     private void fillMetadataIndex(Buffer buffer, int index) {
diff --git a/src/main/java/fr/themode/minestom/entity/EntityManager.java b/src/main/java/fr/themode/minestom/entity/EntityManager.java
index 89c8c17e8..850cc0996 100644
--- a/src/main/java/fr/themode/minestom/entity/EntityManager.java
+++ b/src/main/java/fr/themode/minestom/entity/EntityManager.java
@@ -42,7 +42,7 @@ public class EntityManager {
                 Instance spawningInstance = loginEvent.getSpawningInstance() == null ? instanceManager.createInstanceContainer() : loginEvent.getSpawningInstance();
                 Position position = playerCache.getPosition();
 
-                long[] visibleChunks = ChunkUtils.getVisibleChunks(position);
+                long[] visibleChunks = ChunkUtils.getChunksInRange(position, Main.CHUNK_VIEW_DISTANCE);
                 for (int i = 0; i < visibleChunks.length; i++) {
                     int[] chunkPos = ChunkUtils.getChunkCoord(visibleChunks[i]);
                     int chunkX = chunkPos[0];
diff --git a/src/main/java/fr/themode/minestom/entity/Player.java b/src/main/java/fr/themode/minestom/entity/Player.java
index 8fc182c35..2c9de4b53 100644
--- a/src/main/java/fr/themode/minestom/entity/Player.java
+++ b/src/main/java/fr/themode/minestom/entity/Player.java
@@ -142,7 +142,7 @@ public class Player extends LivingEntity {
 
         setEventCallback(PlayerSpawnEvent.class, event -> {
             System.out.println("SPAWN");
-            setGameMode(GameMode.CREATIVE);
+            setGameMode(GameMode.SURVIVAL);
             teleport(new Position(0, 66, 0));
 
             /*ChickenCreature chickenCreature = new ChickenCreature();
@@ -434,12 +434,9 @@ public class Player extends LivingEntity {
         float dz = newChunk.getChunkZ() - lastChunk.getChunkZ();
         double distance = Math.sqrt(dx * dx + dz * dz);
         boolean isFar = distance >= Main.CHUNK_VIEW_DISTANCE / 2;
-        if (isFar) {
-            updatePlayerPosition();
-        }
 
-        long[] lastVisibleChunks = ChunkUtils.getVisibleChunks(new Position(16 * lastChunk.getChunkX(), 0, 16 * lastChunk.getChunkZ()));
-        long[] updatedVisibleChunks = ChunkUtils.getVisibleChunks(new Position(16 * newChunk.getChunkX(), 0, 16 * newChunk.getChunkZ()));
+        long[] lastVisibleChunks = ChunkUtils.getChunksInRange(new Position(16 * lastChunk.getChunkX(), 0, 16 * lastChunk.getChunkZ()), Main.CHUNK_VIEW_DISTANCE);
+        long[] updatedVisibleChunks = ChunkUtils.getChunksInRange(new Position(16 * newChunk.getChunkX(), 0, 16 * newChunk.getChunkZ()), Main.CHUNK_VIEW_DISTANCE);
         int[] oldChunks = ArrayUtils.getDifferencesBetweenArray(lastVisibleChunks, updatedVisibleChunks);
         int[] newChunks = ArrayUtils.getDifferencesBetweenArray(updatedVisibleChunks, lastVisibleChunks);
 
@@ -461,19 +458,18 @@ public class Player extends LivingEntity {
             int[] chunkPos = ChunkUtils.getChunkCoord(updatedVisibleChunks[index]);
             instance.loadOptionalChunk(chunkPos[0], chunkPos[1], chunk -> {
                 if (chunk == null) {
-                    return; // Cannot load chunk (autoload not enabled)
+                    return; // Cannot load chunk (auto load not enabled)
                 }
                 instance.sendChunk(this, chunk);
-                if (isFar && isLast)
+                if (isFar && isLast) {
                     updatePlayerPosition();
+                }
             });
         }
     }
 
     @Override
     public void teleport(Position position, Runnable callback) {
-        if (instance == null)
-            return;
         super.teleport(position, () -> {
             if (!instance.hasEnabledAutoChunkLoad() && isChunkUnloaded(position.getX(), position.getZ()))
                 return;
@@ -585,7 +581,7 @@ public class Player extends LivingEntity {
         }
 
         OpenWindowPacket openWindowPacket = new OpenWindowPacket();
-        openWindowPacket.windowId = inventory.getUniqueId();
+        openWindowPacket.windowId = inventory.getWindowId();
         openWindowPacket.windowType = inventory.getInventoryType().getWindowType();
         openWindowPacket.title = inventory.getTitle();
         playerConnection.sendPacket(openWindowPacket);
@@ -599,7 +595,7 @@ public class Player extends LivingEntity {
         if (openInventory == null) {
             closeWindowPacket.windowId = 0;
         } else {
-            closeWindowPacket.windowId = openInventory.getUniqueId();
+            closeWindowPacket.windowId = openInventory.getWindowId();
             openInventory.removeViewer(this);
             refreshOpenInventory(null);
         }
@@ -623,7 +619,7 @@ public class Player extends LivingEntity {
         return equipmentPacket;
     }
 
-    protected void updateViewPosition(Chunk chunk) {
+    public void updateViewPosition(Chunk chunk) {
         UpdateViewPositionPacket updateViewPositionPacket = new UpdateViewPositionPacket(chunk);
         playerConnection.sendPacket(updateViewPositionPacket);
     }
diff --git a/src/main/java/fr/themode/minestom/instance/BlockBatch.java b/src/main/java/fr/themode/minestom/instance/BlockBatch.java
index 5c869e974..f0858ad81 100644
--- a/src/main/java/fr/themode/minestom/instance/BlockBatch.java
+++ b/src/main/java/fr/themode/minestom/instance/BlockBatch.java
@@ -51,16 +51,22 @@ public class BlockBatch implements BlockModifier {
         this.data.put(chunk, blockData);
     }
 
-    public void flush() {
+    public void flush(Runnable callback) {
+        int counter = 0;
         for (Map.Entry<Chunk, List<BlockData>> entry : data.entrySet()) {
+            counter++;
             Chunk chunk = entry.getKey();
             List<BlockData> dataList = entry.getValue();
+            boolean isLast = counter == data.size();
             batchesPool.execute(() -> {
                 synchronized (chunk) {
                     for (BlockData data : dataList) {
                         data.apply(chunk);
                     }
-                    instance.sendChunkUpdate(chunk); // TODO partial chunk data
+                    chunk.refreshDataPacket();
+                    instance.sendChunkUpdate(chunk);
+                    if (isLast && callback != null)
+                        callback.run();
                 }
             });
         }
diff --git a/src/main/java/fr/themode/minestom/instance/BlockModifier.java b/src/main/java/fr/themode/minestom/instance/BlockModifier.java
index 59ce41af8..c6de21d88 100644
--- a/src/main/java/fr/themode/minestom/instance/BlockModifier.java
+++ b/src/main/java/fr/themode/minestom/instance/BlockModifier.java
@@ -1,6 +1,7 @@
 package fr.themode.minestom.instance;
 
 import fr.themode.minestom.utils.BlockPosition;
+import fr.themode.minestom.utils.Position;
 
 public interface BlockModifier {
 
@@ -12,8 +13,16 @@ public interface BlockModifier {
         setBlock(blockPosition.getX(), blockPosition.getY(), blockPosition.getZ(), blockId);
     }
 
+    default void setBlock(Position position, short blockId) {
+        setBlock(position.toBlockPosition(), blockId);
+    }
+
     default void setBlock(BlockPosition blockPosition, String blockId) {
         setBlock(blockPosition.getX(), blockPosition.getY(), blockPosition.getZ(), blockId);
     }
 
+    default void setBlock(Position position, String blockId) {
+        setBlock(position.toBlockPosition(), blockId);
+    }
+
 }
diff --git a/src/main/java/fr/themode/minestom/instance/Chunk.java b/src/main/java/fr/themode/minestom/instance/Chunk.java
index 4e436e88c..66ee9fcd1 100644
--- a/src/main/java/fr/themode/minestom/instance/Chunk.java
+++ b/src/main/java/fr/themode/minestom/instance/Chunk.java
@@ -7,8 +7,9 @@ import fr.themode.minestom.net.packet.server.play.ChunkDataPacket;
 import fr.themode.minestom.utils.PacketUtils;
 import fr.themode.minestom.utils.SerializerUtils;
 
-import java.io.*;
-import java.nio.file.Files;
+import java.io.ByteArrayOutputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArraySet;
 
@@ -34,7 +35,6 @@ public class Chunk {
         this.biome = biome;
         this.chunkX = chunkX;
         this.chunkZ = chunkZ;
-        //refreshDataPacket(); // TODO remove
     }
 
     protected void setBlock(byte x, byte y, byte z, short blockId) {
@@ -132,25 +132,6 @@ public class Chunk {
         return result;
     }
 
-    protected void loadFromFile(File file) throws IOException {
-        System.out.println("LOAD FROM FILE");
-        byte[] array = Files.readAllBytes(file.toPath());
-        DataInputStream stream = new DataInputStream(new ByteArrayInputStream(array));
-        this.chunkX = stream.readInt();
-        this.chunkZ = stream.readInt();
-        System.out.println("chunk: " + chunkX + " : " + chunkZ);
-        try {
-            while (true) {
-                int index = stream.readInt();
-                boolean isCustomBlock = stream.readBoolean();
-                short block = stream.readShort();
-            }
-        } catch (EOFException e) {
-            System.out.println("END");
-        }
-
-    }
-
     public ChunkDataPacket getFreshFullDataPacket() {
         ChunkDataPacket fullDataPacket = new ChunkDataPacket();
         fullDataPacket.chunk = this;
diff --git a/src/main/java/fr/themode/minestom/instance/ChunkBatch.java b/src/main/java/fr/themode/minestom/instance/ChunkBatch.java
index a6e10e670..86660d403 100644
--- a/src/main/java/fr/themode/minestom/instance/ChunkBatch.java
+++ b/src/main/java/fr/themode/minestom/instance/ChunkBatch.java
@@ -8,6 +8,9 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.function.Consumer;
 
+/**
+ * Use chunk coordinate (0-16) instead of world's
+ */
 public class ChunkBatch implements BlockModifier {
 
     private static volatile ExecutorService batchesPool = Executors.newFixedThreadPool(Main.THREAD_COUNT_CHUNK_BATCH);
@@ -50,9 +53,9 @@ public class ChunkBatch implements BlockModifier {
                 for (BlockData data : dataList) {
                     data.apply(chunk);
                 }
-                // System.out.println("FINISHED chunk creation " + chunk.getChunkX() + ":" + chunk.getChunkZ());
-                chunk.refreshDataPacket(); // TODO partial refresh instead of full
-                instance.sendChunkUpdate(chunk); // TODO partial chunk data
+
+                chunk.refreshDataPacket();
+                instance.sendChunkUpdate(chunk);
                 if (callback != null)
                     callback.accept(chunk);
             });
diff --git a/src/main/java/fr/themode/minestom/instance/Instance.java b/src/main/java/fr/themode/minestom/instance/Instance.java
index 8fc22ebda..78ad6834c 100644
--- a/src/main/java/fr/themode/minestom/instance/Instance.java
+++ b/src/main/java/fr/themode/minestom/instance/Instance.java
@@ -1,6 +1,7 @@
 package fr.themode.minestom.instance;
 
 import fr.adamaq01.ozao.net.Buffer;
+import fr.themode.minestom.Main;
 import fr.themode.minestom.entity.Entity;
 import fr.themode.minestom.entity.EntityCreature;
 import fr.themode.minestom.entity.ObjectEntity;
@@ -152,16 +153,20 @@ public abstract class Instance implements BlockModifier {
             lastInstance.removeEntity(entity); // If entity is in another instance, remove it from there and add it to this
         }
 
-        // TODO based on distance with players
-        getPlayers().forEach(p -> entity.addViewer(p)); // Add new entity to all players viewable list
-
         if (entity instanceof Player) {
             Player player = (Player) entity;
             sendChunks(player);
-            // Send player all current entity in the instance
-            getObjectEntities().forEach(objectEntity -> objectEntity.addViewer(player));
-            getCreatures().forEach(entityCreature -> entityCreature.addViewer(player));
-            getPlayers().forEach(p -> p.addViewer(player));
+
+            // Send player all visible entities
+            long[] visibleChunksEntity = ChunkUtils.getChunksInRange(entity.getPosition(), Main.ENTITY_VIEW_DISTANCE);
+            for (long chunkIndex : visibleChunksEntity) {
+                getEntitiesInChunk(chunkIndex).forEach(ent -> {
+                    ent.addViewer(player);
+                    if (ent instanceof Player) {
+                        player.addViewer((Player) ent);
+                    }
+                });
+            }
         }
 
         Chunk chunk = getChunkAt(entity.getPosition());
diff --git a/src/main/java/fr/themode/minestom/instance/InstanceContainer.java b/src/main/java/fr/themode/minestom/instance/InstanceContainer.java
index ae0e7a138..f4b4efa12 100644
--- a/src/main/java/fr/themode/minestom/instance/InstanceContainer.java
+++ b/src/main/java/fr/themode/minestom/instance/InstanceContainer.java
@@ -207,19 +207,15 @@ public class InstanceContainer extends Instance {
 
     @Override
     public void sendChunk(Player player, Chunk chunk) {
-        Buffer chunkData = chunk.getFullDataPacket();
-        if (chunkData == null) {
-            PacketWriter.writeCallbackPacket(chunk.getFreshFullDataPacket(), buffer -> {
-                buffer.getData().retain(1).markReaderIndex();
-                player.getPlayerConnection().sendUnencodedPacket(buffer);
-                buffer.getData().resetReaderIndex();
-                chunk.setFullDataPacket(buffer);
-            });
-        } else {
-            chunkData.getData().retain(1).markReaderIndex();
+        PacketWriter.writeCallbackPacket(chunk.getFreshFullDataPacket(), buffer -> {
+            buffer.getData().retain(1).markReaderIndex();
+            player.getPlayerConnection().sendUnencodedPacket(buffer);
+            buffer.getData().resetReaderIndex();
+        });
+        // TODO use cached chunk data
+            /*chunkData.getData().retain(1).markReaderIndex();
             player.getPlayerConnection().sendUnencodedPacket(chunkData);
-            chunkData.getData().resetReaderIndex();
-        }
+            chunkData.getData().resetReaderIndex();*/
     }
 
     @Override
diff --git a/src/main/java/fr/themode/minestom/inventory/Inventory.java b/src/main/java/fr/themode/minestom/inventory/Inventory.java
index 6742aee18..7e03c648e 100644
--- a/src/main/java/fr/themode/minestom/inventory/Inventory.java
+++ b/src/main/java/fr/themode/minestom/inventory/Inventory.java
@@ -50,7 +50,7 @@ public class Inventory implements InventoryModifier, InventoryClickHandler, View
         return title;
     }
 
-    public int getUniqueId() {
+    public int getWindowId() {
         return id;
     }
 
@@ -77,7 +77,7 @@ public class Inventory implements InventoryModifier, InventoryClickHandler, View
         return Arrays.copyOf(itemStacks, itemStacks.length);
     }
 
-    public void updateItems() {
+    public void update() {
         WindowItemsPacket windowItemsPacket = getWindowItemsPacket();
         getViewers().forEach(p -> p.getPlayerConnection().sendPacket(windowItemsPacket));
     }
@@ -117,7 +117,7 @@ public class Inventory implements InventoryModifier, InventoryClickHandler, View
 
     private WindowItemsPacket getWindowItemsPacket() {
         WindowItemsPacket windowItemsPacket = new WindowItemsPacket();
-        windowItemsPacket.windowId = getUniqueId();
+        windowItemsPacket.windowId = getWindowId();
         windowItemsPacket.count = (short) itemStacks.length;
         windowItemsPacket.items = itemStacks;
         return windowItemsPacket;
diff --git a/src/main/java/fr/themode/minestom/inventory/InventoryProperty.java b/src/main/java/fr/themode/minestom/inventory/InventoryProperty.java
new file mode 100644
index 000000000..780ceb3a9
--- /dev/null
+++ b/src/main/java/fr/themode/minestom/inventory/InventoryProperty.java
@@ -0,0 +1,40 @@
+package fr.themode.minestom.inventory;
+
+public enum InventoryProperty {
+
+    FURNACE_FIRE_ICON((short) 0),
+    FURNACE_MAXIMUM_FUEL_BURN_TIME((short) 1),
+    FURNACE_PROGRESS_ARROW((short) 2),
+    FURNACE_MAXIMUM_PROGRESS((short) 3),
+
+    ENCHANTMENT_TABLE_LEVEL_REQUIREMENT_TOP((short) 0),
+    ENCHANTMENT_TABLE_LEVEL_REQUIREMENT_MIDDLE((short) 1),
+    ENCHANTMENT_TABLE_LEVEL_REQUIREMENT_BOTTOM((short) 2),
+    ENCHANTMENT_TABLE_SEED((short) 3),
+    ENCHANTMENT_TABLE_ENCH_ID_TOP((short) 4),
+    ENCHANTMENT_TABLE_ENCH_ID_MIDDLE((short) 5),
+    ENCHANTMENT_TABLE_ENCH_ID_BOTTOM((short) 6),
+    ENCHANTMENT_TABLE_ENCH_LEVEL_TOP((short) 7),
+    ENCHANTMENT_TABLE_ENCH_LEVEL_MIDDLE((short) 8),
+    ENCHANTMENT_TABLE_ENCH_LEVEL_BOTTOM((short) 9),
+
+    BEACON_POWER_LEVEL((short) 0),
+    BEACON_FIRST_POTION((short) 1),
+    BEACON_SECOND_POTION((short) 2),
+
+    ANVIL_REPAIR_COST((short) 0),
+
+    BREWING_STAND_BREW_TIME((short) 0),
+    BREWING_STAND_FUEL_TIME((short) 1);
+
+
+    private short property;
+
+    InventoryProperty(short property) {
+        this.property = property;
+    }
+
+    public short getProperty() {
+        return property;
+    }
+}
diff --git a/src/main/java/fr/themode/minestom/inventory/type/VillagerInventory.java b/src/main/java/fr/themode/minestom/inventory/type/VillagerInventory.java
new file mode 100644
index 000000000..110daf8e8
--- /dev/null
+++ b/src/main/java/fr/themode/minestom/inventory/type/VillagerInventory.java
@@ -0,0 +1,91 @@
+package fr.themode.minestom.inventory.type;
+
+import fr.themode.minestom.inventory.Inventory;
+import fr.themode.minestom.inventory.InventoryType;
+import fr.themode.minestom.net.packet.server.play.TradeListPacket;
+import fr.themode.minestom.utils.ArrayUtils;
+
+public class VillagerInventory extends Inventory {
+
+    protected TradeListPacket tradeListPacket;
+
+    public VillagerInventory(String title) {
+        super(InventoryType.MERCHANT, title);
+        setupPacket();
+    }
+
+    public TradeListPacket.Trade[] getTrades() {
+        return tradeListPacket.trades;
+    }
+
+    public void addTrade(TradeListPacket.Trade trade) {
+        TradeListPacket.Trade[] oldTrades = getTrades();
+        int length = oldTrades.length + 1;
+        TradeListPacket.Trade[] trades = new TradeListPacket.Trade[length];
+        System.arraycopy(oldTrades, 0, trades, 0, oldTrades.length);
+        trades[length] = trade;
+        this.tradeListPacket.trades = trades;
+        update();
+    }
+
+    public void removeTrade(int index) {
+        TradeListPacket.Trade[] oldTrades = getTrades();
+        int length = oldTrades.length - 1;
+        TradeListPacket.Trade[] trades = new TradeListPacket.Trade[length];
+        ArrayUtils.removeElement(trades, index);
+        this.tradeListPacket.trades = trades;
+        update();
+    }
+
+    public int getVillagerLevel() {
+        return tradeListPacket.villagerLevel;
+    }
+
+    public void setVillagerLevel(int level) {
+        this.tradeListPacket.villagerLevel = level;
+        update();
+    }
+
+    public int getExperience() {
+        return tradeListPacket.experience;
+    }
+
+    public void setExperience(int experience) {
+        this.tradeListPacket.experience = experience;
+        update();
+    }
+
+    public boolean isRegularVillager() {
+        return tradeListPacket.regularVillager;
+    }
+
+    public void setRegularVillager(boolean regularVillager) {
+        this.tradeListPacket.regularVillager = regularVillager;
+        update();
+    }
+
+    public boolean canRestock() {
+        return tradeListPacket.canRestock;
+    }
+
+    public void setCanRestock(boolean canRestock) {
+        this.tradeListPacket.canRestock = canRestock;
+        update();
+    }
+
+    @Override
+    public void update() {
+        super.update();
+        sendPacketToViewers(tradeListPacket); // Refresh window
+    }
+
+    private void setupPacket() {
+        this.tradeListPacket = new TradeListPacket();
+        this.tradeListPacket.windowId = getWindowId();
+        this.tradeListPacket.trades = new TradeListPacket.Trade[0];
+        this.tradeListPacket.villagerLevel = 0;
+        this.tradeListPacket.experience = 0;
+        this.tradeListPacket.regularVillager = false;
+        this.tradeListPacket.canRestock = false;
+    }
+}
diff --git a/src/main/java/fr/themode/minestom/listener/ChatMessageListener.java b/src/main/java/fr/themode/minestom/listener/ChatMessageListener.java
index 6525e1ace..c12b9211c 100644
--- a/src/main/java/fr/themode/minestom/listener/ChatMessageListener.java
+++ b/src/main/java/fr/themode/minestom/listener/ChatMessageListener.java
@@ -7,8 +7,9 @@ import fr.themode.minestom.net.packet.client.play.ClientChatMessagePacket;
 public class ChatMessageListener {
 
     public static void listener(ClientChatMessagePacket packet, Player player) {
-        // TODO commands check
-        Main.getConnectionManager().getOnlinePlayers().forEach(p -> p.sendMessage(String.format("<%s> %s", player.getUsername(), packet.message)));
+        String message = packet.message;
+        Main.getConnectionManager().getOnlinePlayers().forEach(p -> p.sendMessage(String.format("<%s> %s", player.getUsername(), message)));
+
     }
 
 }
diff --git a/src/main/java/fr/themode/minestom/net/ConnectionManager.java b/src/main/java/fr/themode/minestom/net/ConnectionManager.java
index 4b1dd47ac..8e179df61 100644
--- a/src/main/java/fr/themode/minestom/net/ConnectionManager.java
+++ b/src/main/java/fr/themode/minestom/net/ConnectionManager.java
@@ -4,11 +4,12 @@ import fr.themode.minestom.entity.Player;
 import fr.themode.minestom.net.player.PlayerConnection;
 
 import java.util.*;
+import java.util.concurrent.CopyOnWriteArraySet;
 
 public class ConnectionManager {
 
-    private volatile Set<Player> players = new HashSet<>();
-    private volatile Map<PlayerConnection, Player> connectionPlayerMap = new HashMap<>();
+    private Set<Player> players = new CopyOnWriteArraySet<>();
+    private Map<PlayerConnection, Player> connectionPlayerMap = Collections.synchronizedMap(new HashMap<>());
 
     public Player getPlayer(PlayerConnection connection) {
         return connectionPlayerMap.get(connection);
diff --git a/src/main/java/fr/themode/minestom/net/packet/client/handler/ClientPacketsHandler.java b/src/main/java/fr/themode/minestom/net/packet/client/handler/ClientPacketsHandler.java
index 597ea5aba..2b3953143 100644
--- a/src/main/java/fr/themode/minestom/net/packet/client/handler/ClientPacketsHandler.java
+++ b/src/main/java/fr/themode/minestom/net/packet/client/handler/ClientPacketsHandler.java
@@ -15,7 +15,10 @@ public class ClientPacketsHandler {
     }
 
     public ClientPacket getPacketInstance(int id) {
-        return constructorAccessMap.get(id).newInstance();
+        ClientPacket packet = constructorAccessMap.get(id).newInstance();
+        if (packet == null)
+            System.err.println("Packet id 0x" + Integer.toHexString(id) + " isn't registered!");
+        return packet;
     }
 
 }
diff --git a/src/main/java/fr/themode/minestom/net/packet/server/play/ExplosionPacket.java b/src/main/java/fr/themode/minestom/net/packet/server/play/ExplosionPacket.java
new file mode 100644
index 000000000..7f42c6f7b
--- /dev/null
+++ b/src/main/java/fr/themode/minestom/net/packet/server/play/ExplosionPacket.java
@@ -0,0 +1,31 @@
+package fr.themode.minestom.net.packet.server.play;
+
+import fr.adamaq01.ozao.net.Buffer;
+import fr.themode.minestom.net.packet.server.ServerPacket;
+
+public class ExplosionPacket implements ServerPacket {
+
+    public float x, y, z;
+    public float radius; // UNUSED
+    public byte[] records;
+    public float playerMotionX, playerMotionY, playerMotionZ;
+
+    @Override
+    public void write(Buffer buffer) {
+        buffer.putFloat(x);
+        buffer.putFloat(y);
+        buffer.putFloat(z);
+        buffer.putFloat(radius);
+        buffer.putInt(records.length);
+        for (byte record : records)
+            buffer.putByte(record);
+        buffer.putFloat(playerMotionX);
+        buffer.putFloat(playerMotionY);
+        buffer.putFloat(playerMotionZ);
+    }
+
+    @Override
+    public int getId() {
+        return 0x1C;
+    }
+}
diff --git a/src/main/java/fr/themode/minestom/net/packet/server/play/TradeListPacket.java b/src/main/java/fr/themode/minestom/net/packet/server/play/TradeListPacket.java
new file mode 100644
index 000000000..2576ec613
--- /dev/null
+++ b/src/main/java/fr/themode/minestom/net/packet/server/play/TradeListPacket.java
@@ -0,0 +1,66 @@
+package fr.themode.minestom.net.packet.server.play;
+
+import fr.adamaq01.ozao.net.Buffer;
+import fr.themode.minestom.item.ItemStack;
+import fr.themode.minestom.net.packet.server.ServerPacket;
+import fr.themode.minestom.utils.Utils;
+
+public class TradeListPacket implements ServerPacket {
+
+    public int windowId;
+    public Trade[] trades;
+    public int villagerLevel;
+    public int experience;
+    public boolean regularVillager;
+    public boolean canRestock;
+
+    @Override
+    public void write(Buffer buffer) {
+        Utils.writeVarInt(buffer, windowId);
+        buffer.putByte((byte) trades.length);
+        for (Trade trade : trades) {
+            trade.write(buffer);
+        }
+        Utils.writeVarInt(buffer, villagerLevel);
+        Utils.writeVarInt(buffer, experience);
+        buffer.putBoolean(regularVillager);
+        buffer.putBoolean(canRestock);
+    }
+
+    @Override
+    public int getId() {
+        return 0x27;
+    }
+
+    public static class Trade {
+
+        public ItemStack inputItem1;
+        public ItemStack result;
+        public ItemStack inputItem2;
+        public boolean tradeDisabled;
+        public int tradeUsesNumber;
+        public int maxTradeUsesNumber;
+        public int exp;
+        public int specialPrice;
+        public float priceMultiplier;
+        public int demand;
+
+
+        private void write(Buffer buffer) {
+            Utils.writeItemStack(buffer, inputItem1);
+            Utils.writeItemStack(buffer, result);
+            buffer.putBoolean(inputItem2 != null);
+            if (inputItem2 != null)
+                Utils.writeItemStack(buffer, inputItem2);
+            buffer.putBoolean(tradeDisabled);
+            buffer.putInt(tradeUsesNumber);
+            buffer.putInt(maxTradeUsesNumber);
+            buffer.putInt(exp);
+            buffer.putInt(specialPrice);
+            buffer.putFloat(priceMultiplier);
+            buffer.putInt(demand);
+        }
+
+    }
+
+}
diff --git a/src/main/java/fr/themode/minestom/net/packet/server/play/WindowPropertyPacket.java b/src/main/java/fr/themode/minestom/net/packet/server/play/WindowPropertyPacket.java
new file mode 100644
index 000000000..e1fad3dd4
--- /dev/null
+++ b/src/main/java/fr/themode/minestom/net/packet/server/play/WindowPropertyPacket.java
@@ -0,0 +1,23 @@
+package fr.themode.minestom.net.packet.server.play;
+
+import fr.adamaq01.ozao.net.Buffer;
+import fr.themode.minestom.net.packet.server.ServerPacket;
+
+public class WindowPropertyPacket implements ServerPacket {
+
+    public byte windowId;
+    public short property;
+    public short value;
+
+    @Override
+    public void write(Buffer buffer) {
+        buffer.putByte(windowId);
+        buffer.putShort(property);
+        buffer.putShort(value);
+    }
+
+    @Override
+    public int getId() {
+        return 0x15;
+    }
+}
diff --git a/src/main/java/fr/themode/minestom/utils/ArrayUtils.java b/src/main/java/fr/themode/minestom/utils/ArrayUtils.java
index af3a993d1..7b533f715 100644
--- a/src/main/java/fr/themode/minestom/utils/ArrayUtils.java
+++ b/src/main/java/fr/themode/minestom/utils/ArrayUtils.java
@@ -17,6 +17,10 @@ public class ArrayUtils {
         return result;
     }
 
+    public static void removeElement(Object[] arr, int index) {
+        System.arraycopy(arr, index + 1, arr, index, arr.length - 1 - index);
+    }
+
     /**
      * @param a
      * @param b
diff --git a/src/main/java/fr/themode/minestom/utils/ChunkUtils.java b/src/main/java/fr/themode/minestom/utils/ChunkUtils.java
index 9bf1f2bd3..2e2b33b21 100644
--- a/src/main/java/fr/themode/minestom/utils/ChunkUtils.java
+++ b/src/main/java/fr/themode/minestom/utils/ChunkUtils.java
@@ -1,7 +1,5 @@
 package fr.themode.minestom.utils;
 
-import fr.themode.minestom.Main;
-
 public class ChunkUtils {
 
     public static long getChunkIndex(int chunkX, int chunkZ) {
@@ -14,12 +12,11 @@ public class ChunkUtils {
         return new int[]{chunkX, chunkZ};
     }
 
-    public static long[] getVisibleChunks(final Position position) {
-        final int viewDistance = Main.CHUNK_VIEW_DISTANCE;
+    public static long[] getChunksInRange(final Position position, int range) {
 
-        long[] visibleChunks = new long[MathUtils.square(viewDistance + 1)];
-        final int startLoop = -(viewDistance / 2);
-        final int endLoop = viewDistance / 2 + 1;
+        long[] visibleChunks = new long[MathUtils.square(range + 1)];
+        final int startLoop = -(range / 2);
+        final int endLoop = range / 2 + 1;
         int counter = 0;
         for (int x = startLoop; x < endLoop; x++) {
             for (int z = startLoop; z < endLoop; z++) {
diff --git a/src/main/java/fr/themode/minestom/utils/EntityUtils.java b/src/main/java/fr/themode/minestom/utils/EntityUtils.java
new file mode 100644
index 000000000..2355bf865
--- /dev/null
+++ b/src/main/java/fr/themode/minestom/utils/EntityUtils.java
@@ -0,0 +1,29 @@
+package fr.themode.minestom.utils;
+
+import fr.themode.minestom.Main;
+import fr.themode.minestom.entity.Entity;
+import fr.themode.minestom.instance.Chunk;
+
+public class EntityUtils {
+
+    public static boolean areVisible(Entity ent1, Entity ent2) {
+        if (ent1.getInstance() == null || ent2.getInstance() == null)
+            return false;
+        if (!ent1.getInstance().equals(ent2.getInstance()))
+            return false;
+
+        Chunk chunk = ent1.getInstance().getChunkAt(ent1.getPosition());
+
+        long[] visibleChunksEntity = ChunkUtils.getChunksInRange(ent2.getPosition(), Main.ENTITY_VIEW_DISTANCE);
+        for (long visibleChunk : visibleChunksEntity) {
+            int[] chunkPos = ChunkUtils.getChunkCoord(visibleChunk);
+            int chunkX = chunkPos[0];
+            int chunkZ = chunkPos[1];
+            if (chunk.getChunkX() == chunkX && chunk.getChunkZ() == chunkZ)
+                return true;
+        }
+
+        return false;
+    }
+
+}
diff --git a/src/main/java/fr/themode/minestom/utils/Position.java b/src/main/java/fr/themode/minestom/utils/Position.java
index 16b7bf785..1e16cb5f9 100644
--- a/src/main/java/fr/themode/minestom/utils/Position.java
+++ b/src/main/java/fr/themode/minestom/utils/Position.java
@@ -132,6 +132,10 @@ public class Position {
         this.pitch = pitch;
     }
 
+    public BlockPosition toBlockPosition() {
+        return new BlockPosition((int) getX(), (int) getY(), (int) getZ());
+    }
+
     @Override
     public String toString() {
         return "Position[" + x + ":" + y + ":" + z + "] (" + yaw + "/" + pitch + ")";