diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/MinecraftPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/MinecraftPacket.java
index e54ee770..1722f42b 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/MinecraftPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/MinecraftPacket.java
@@ -32,13 +32,18 @@ public interface MinecraftPacket {
 
   boolean handle(MinecraftSessionHandler handler);
 
-  default int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+  default int decodeExpectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
       ProtocolVersion version) {
     return -1;
   }
 
-  default int expectedMinLength(ByteBuf buf, ProtocolUtils.Direction direction,
+  default int decodeExpectedMinLength(ByteBuf buf, ProtocolUtils.Direction direction,
       ProtocolVersion version) {
     return 0;
   }
+
+  default int encodeSizeHint(ProtocolUtils.Direction direction,
+      ProtocolVersion version) {
+    return -1;
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/ProtocolUtils.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/ProtocolUtils.java
index 6e8ba6ac..efc0ed17 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/ProtocolUtils.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/ProtocolUtils.java
@@ -292,6 +292,17 @@ public enum ProtocolUtils {
     return str;
   }
 
+  /**
+   * Determines the size of the written {@code str} if encoded as a VarInt-prefixed UTF-8 string.
+   *
+   * @param str the string to write
+   * @return the encoded size
+   */
+  public static int stringSizeHint(CharSequence str) {
+    int size = ByteBufUtil.utf8Bytes(str);
+    return varIntBytes(size) + size;
+  }
+
   /**
    * Writes the specified {@code str} to the {@code buf} with a VarInt prefix.
    *
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftDecoder.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftDecoder.java
index 5389de73..35ddccd5 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftDecoder.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftDecoder.java
@@ -96,8 +96,8 @@ public class MinecraftDecoder extends ChannelInboundHandlerAdapter {
   }
 
   private void doLengthSanityChecks(ByteBuf buf, MinecraftPacket packet) throws Exception {
-    int expectedMinLen = packet.expectedMinLength(buf, direction, registry.version);
-    int expectedMaxLen = packet.expectedMaxLength(buf, direction, registry.version);
+    int expectedMinLen = packet.decodeExpectedMinLength(buf, direction, registry.version);
+    int expectedMaxLen = packet.decodeExpectedMaxLength(buf, direction, registry.version);
     if (expectedMaxLen != -1 && buf.readableBytes() > expectedMaxLen) {
       throw handleOverflow(packet, expectedMaxLen, buf.readableBytes());
     }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftEncoder.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftEncoder.java
index 7133f1d2..4af366ce 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftEncoder.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftEncoder.java
@@ -54,6 +54,19 @@ public class MinecraftEncoder extends MessageToByteEncoder<MinecraftPacket> {
     msg.encode(out, direction, registry.version);
   }
 
+  @Override
+  protected ByteBuf allocateBuffer(ChannelHandlerContext ctx, MinecraftPacket msg,
+      boolean preferDirect) throws Exception {
+    int hint = msg.encodeSizeHint(direction, registry.version);
+    if (hint < 0) {
+      return super.allocateBuffer(ctx, msg, preferDirect);
+    }
+
+    int packetId = this.registry.getPacketId(msg);
+    int totalHint = ProtocolUtils.varIntBytes(packetId) + hint;
+    return preferDirect ? ctx.alloc().ioBuffer(totalHint) : ctx.alloc().heapBuffer(totalHint);
+  }
+
   public void setProtocolVersion(final ProtocolVersion protocolVersion) {
     this.registry = state.getProtocolRegistry(direction, protocolVersion);
   }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftVarintFrameDecoder.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftVarintFrameDecoder.java
index 1301ed5b..7d4d8d6d 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftVarintFrameDecoder.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftVarintFrameDecoder.java
@@ -131,8 +131,8 @@ public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder {
 
     // We 'technically' have the incoming bytes of a payload here, and so, these can actually parse
     // the packet if needed, so, we'll take advantage of the existing methods
-    int expectedMinLen = packet.expectedMinLength(in, direction, registry.version);
-    int expectedMaxLen = packet.expectedMaxLength(in, direction, registry.version);
+    int expectedMinLen = packet.decodeExpectedMinLength(in, direction, registry.version);
+    int expectedMaxLen = packet.decodeExpectedMaxLength(in, direction, registry.version);
     if (expectedMaxLen != -1 && payloadLength > expectedMaxLen) {
       throw handleOverflow(packet, expectedMaxLen, in.readableBytes());
     }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/AvailableCommandsPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/AvailableCommandsPacket.java
index 08fe23b2..d3fc3a82 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/AvailableCommandsPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/AvailableCommandsPacket.java
@@ -362,4 +362,12 @@ public class AvailableCommandsPacket implements MinecraftPacket {
       return builder.buildFuture();
     }
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    // This is a very complex packet to encode. Paper 1.21.10 + Velocity with Spark has a size of
+    // 30,334, but this is likely on the lower side. We'll use 128KiB as a more realistically-sized
+    // amount.
+    return 128 * 1024;
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/EncryptionResponsePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/EncryptionResponsePacket.java
index d6591e7b..fedb67a5 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/EncryptionResponsePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/EncryptionResponsePacket.java
@@ -107,7 +107,7 @@ public class EncryptionResponsePacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
+  public int decodeExpectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
     // It turns out these come out to the same length, whether we're talking >=1.8 or not.
     // The length prefix always winds up being 2 bytes.
     int base = 256 + 2 + 2;
@@ -123,8 +123,8 @@ public class EncryptionResponsePacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMinLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
-    int base = expectedMaxLength(buf, direction, version);
+  public int decodeExpectedMinLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
+    int base = decodeExpectedMaxLength(buf, direction, version);
     if (version.noLessThan(ProtocolVersion.MINECRAFT_1_19)) {
       // These are "optional"
       base -= 128 + 8;
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/HandshakePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/HandshakePacket.java
index 9eb7a93e..88cb3688 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/HandshakePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/HandshakePacket.java
@@ -24,6 +24,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import io.netty.buffer.ByteBuf;
 
 public class HandshakePacket implements MinecraftPacket {
@@ -108,14 +109,21 @@ public class HandshakePacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMinLength(ByteBuf buf, ProtocolUtils.Direction direction,
+  public int decodeExpectedMinLength(ByteBuf buf, ProtocolUtils.Direction direction,
                                ProtocolVersion version) {
     return 7;
   }
 
   @Override
-  public int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+  public int decodeExpectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
                                ProtocolVersion version) {
     return 9 + (MAXIMUM_HOSTNAME_LENGTH * 3);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    // We could compute an exact size, but 4KiB ought to be enough to encode all reasonable
+    // sizes of this packet.
+    return 4 * 1024;
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginAcknowledgedPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginAcknowledgedPacket.java
index dad9e08d..16cf519b 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginAcknowledgedPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginAcknowledgedPacket.java
@@ -36,7 +36,7 @@ public class LoginAcknowledgedPacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+  public int decodeExpectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
                                ProtocolVersion version) {
     return 0;
   }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginMessagePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginMessagePacket.java
index 682785eb..2fa82e92 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginMessagePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginMessagePacket.java
@@ -21,6 +21,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
@@ -86,4 +87,9 @@ public class LoginPluginMessagePacket extends DeferredByteBufHolder implements M
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    return content().readableBytes();
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginResponsePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginResponsePacket.java
index dee33c13..e7d9443d 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginResponsePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginPluginResponsePacket.java
@@ -21,6 +21,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
@@ -88,4 +89,9 @@ public class LoginPluginResponsePacket extends DeferredByteBufHolder implements
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    return content().readableBytes();
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/PluginMessagePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/PluginMessagePacket.java
index d78ed833..ecf2887f 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/PluginMessagePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/PluginMessagePacket.java
@@ -23,6 +23,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
 import io.netty.buffer.ByteBuf;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
@@ -143,4 +144,9 @@ public class PluginMessagePacket extends DeferredByteBufHolder implements Minecr
   public PluginMessagePacket touch(Object hint) {
     return (PluginMessagePacket) super.touch(hint);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    return content().readableBytes();
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerDataPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerDataPacket.java
index 610462a9..325a3c9d 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerDataPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerDataPacket.java
@@ -22,6 +22,7 @@ import com.velocitypowered.api.util.Favicon;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import com.velocitypowered.proxy.protocol.packet.chat.ComponentHolder;
 import io.netty.buffer.ByteBuf;
 import org.jetbrains.annotations.Nullable;
@@ -121,4 +122,9 @@ public class ServerDataPacket implements MinecraftPacket {
   public void setSecureChatEnforced(boolean secureChatEnforced) {
     this.secureChatEnforced = secureChatEnforced;
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    return 8 * 1024;
+  }
 }
\ No newline at end of file
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginPacket.java
index 74eabb5c..65693cd8 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginPacket.java
@@ -150,7 +150,7 @@ public class ServerLoginPacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
+  public int decodeExpectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
     // Accommodate the rare (but likely malicious) use of UTF-8 usernames, since it is technically
     // legal on the protocol level.
     int base = 1 + (16 * 3);
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginSuccessPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginSuccessPacket.java
index 1e70568f..322cd9b1 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginSuccessPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginSuccessPacket.java
@@ -23,6 +23,7 @@ import com.velocitypowered.api.util.UuidUtils;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import com.velocitypowered.proxy.util.VelocityProperties;
 import io.netty.buffer.ByteBuf;
 import java.util.List;
@@ -132,4 +133,11 @@ public class ServerLoginSuccessPacket implements MinecraftPacket {
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    // We could compute an exact size, but 4KiB ought to be enough to encode all reasonable
+    // sizes of this packet.
+    return 4 * 1024;
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerboundCustomClickActionPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerboundCustomClickActionPacket.java
index 2092b260..6b846c23 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerboundCustomClickActionPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerboundCustomClickActionPacket.java
@@ -21,6 +21,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
 import io.netty.buffer.ByteBuf;
 
@@ -45,4 +46,8 @@ public class ServerboundCustomClickActionPacket extends DeferredByteBufHolder im
     return handler.handle(this);
   }
 
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    return content().readableBytes();
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusPingPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusPingPacket.java
index 15999e61..30236704 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusPingPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusPingPacket.java
@@ -44,12 +44,12 @@ public class StatusPingPacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
+  public int decodeExpectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
     return 8;
   }
 
   @Override
-  public int expectedMinLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
+  public int decodeExpectedMinLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
     return 8;
   }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusRequestPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusRequestPacket.java
index 46dc0401..870d9909 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusRequestPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusRequestPacket.java
@@ -53,7 +53,7 @@ public class StatusRequestPacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
+  public int decodeExpectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
     return 0;
   }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusResponsePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusResponsePacket.java
index 8591fa03..20fada4b 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusResponsePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/StatusResponsePacket.java
@@ -21,6 +21,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import io.netty.buffer.ByteBuf;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
@@ -66,4 +67,9 @@ public class StatusResponsePacket implements MinecraftPacket {
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    return ProtocolUtils.stringSizeHint(this.status);
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/UpsertPlayerInfoPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/UpsertPlayerInfoPacket.java
index 35bf4a96..9ef40ef0 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/UpsertPlayerInfoPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/UpsertPlayerInfoPacket.java
@@ -36,6 +36,8 @@ import org.jetbrains.annotations.Nullable;
 
 public class UpsertPlayerInfoPacket implements MinecraftPacket {
 
+  private static final Action[] ALL_ACTIONS = Action.class.getEnumConstants();
+
   private final EnumSet<Action> actions;
   private final List<Entry> entries;
 
@@ -85,14 +87,13 @@ public class UpsertPlayerInfoPacket implements MinecraftPacket {
   @Override
   public void decode(ByteBuf buf, ProtocolUtils.Direction direction,
       ProtocolVersion protocolVersion) {
-    Action[] actions = Action.class.getEnumConstants();
-    byte[] bytes = new byte[-Math.floorDiv(-actions.length, 8)];
+    byte[] bytes = new byte[-Math.floorDiv(-ALL_ACTIONS.length, 8)];
     buf.readBytes(bytes);
     BitSet actionSet = BitSet.valueOf(bytes);
 
-    for (int idx = 0; idx < actions.length; idx++) {
+    for (int idx = 0; idx < ALL_ACTIONS.length; idx++) {
       if (actionSet.get(idx)) {
-        addAction(actions[idx]);
+        addAction(ALL_ACTIONS[idx]);
       }
     }
 
@@ -109,14 +110,13 @@ public class UpsertPlayerInfoPacket implements MinecraftPacket {
   @Override
   public void encode(ByteBuf buf, ProtocolUtils.Direction direction,
       ProtocolVersion protocolVersion) {
-    Action[] actions = Action.class.getEnumConstants();
-    BitSet set = new BitSet(actions.length);
-    for (int idx = 0; idx < actions.length; idx++) {
-      set.set(idx, this.actions.contains(actions[idx]));
+    BitSet set = new BitSet(ALL_ACTIONS.length);
+    for (int idx = 0; idx < ALL_ACTIONS.length; idx++) {
+      set.set(idx, this.actions.contains(ALL_ACTIONS[idx]));
     }
 
     byte[] bytes = set.toByteArray();
-    buf.writeBytes(Arrays.copyOf(bytes, -Math.floorDiv(-actions.length, 8)));
+    buf.writeBytes(Arrays.copyOf(bytes, -Math.floorDiv(-ALL_ACTIONS.length, 8)));
 
     ProtocolUtils.writeVarInt(buf, this.entries.size());
     for (Entry entry : this.entries) {
@@ -133,12 +133,6 @@ public class UpsertPlayerInfoPacket implements MinecraftPacket {
     return handler.handle(this);
   }
 
-  public BitSet readFixedBitSet(ByteBuf buf, int param0) {
-    byte[] var0 = new byte[-Math.floorDiv(-param0, 8)];
-    buf.readBytes(var0);
-    return BitSet.valueOf(var0);
-  }
-
   public enum Action {
     ADD_PLAYER((ignored, buf, info) -> { // read
       info.profile = new GameProfile(
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/CodeOfConductPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/CodeOfConductPacket.java
index 44adb743..41433307 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/CodeOfConductPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/CodeOfConductPacket.java
@@ -44,4 +44,9 @@ public class CodeOfConductPacket extends DeferredByteBufHolder implements Minecr
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    return content().readableBytes();
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/FinishedUpdatePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/FinishedUpdatePacket.java
index b4d93ec4..20d40fd4 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/FinishedUpdatePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/FinishedUpdatePacket.java
@@ -40,7 +40,7 @@ public class FinishedUpdatePacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+  public int decodeExpectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
                                ProtocolVersion version) {
     return 0;
   }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/RegistrySyncPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/RegistrySyncPacket.java
index ef0ee47a..2d9ed230 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/RegistrySyncPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/RegistrySyncPacket.java
@@ -21,6 +21,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
 import io.netty.buffer.ByteBuf;
 
@@ -47,4 +48,9 @@ public class RegistrySyncPacket extends DeferredByteBufHolder implements Minecra
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    return content().readableBytes();
+  }
 }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/StartUpdatePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/StartUpdatePacket.java
index 8d4585d8..d41265ce 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/StartUpdatePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/StartUpdatePacket.java
@@ -40,7 +40,7 @@ public class StartUpdatePacket implements MinecraftPacket {
   }
 
   @Override
-  public int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+  public int decodeExpectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
                                ProtocolVersion version) {
     return 0;
   }
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/TagsUpdatePacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/TagsUpdatePacket.java
index 6d462fb2..c0cf414e 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/TagsUpdatePacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/TagsUpdatePacket.java
@@ -22,6 +22,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import io.netty.buffer.ByteBuf;
 
 import java.util.Map;
@@ -79,4 +80,22 @@ public class TagsUpdatePacket implements MinecraftPacket {
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);
   }
+
+  @Override
+  public int encodeSizeHint(Direction direction, ProtocolVersion version) {
+    int size = ProtocolUtils.varIntBytes(tags.size());
+    for (Map.Entry<String, Map<String, int[]>> entry : tags.entrySet()) {
+      size += ProtocolUtils.stringSizeHint(entry.getKey());
+      size += ProtocolUtils.varIntBytes(entry.getValue().size());
+      for (Map.Entry<String, int[]> innerEntry : entry.getValue().entrySet()) {
+        size += ProtocolUtils.stringSizeHint(innerEntry.getKey());
+        size += ProtocolUtils.varIntBytes(innerEntry.getValue().length);
+        for (int innerEntryValue : innerEntry.getValue()) {
+          size += ProtocolUtils.varIntBytes(innerEntryValue);
+        }
+      }
+    }
+
+    return size;
+  }
 }