diff --git a/src/main/java/net/minestom/server/chat/ChatClickEvent.java b/src/main/java/net/minestom/server/chat/ChatClickEvent.java
index ad82358d3..ec5cbd1b4 100644
--- a/src/main/java/net/minestom/server/chat/ChatClickEvent.java
+++ b/src/main/java/net/minestom/server/chat/ChatClickEvent.java
@@ -1,5 +1,7 @@
 package net.minestom.server.chat;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * Represents a click event for a specific portion of the message.
  */
@@ -8,7 +10,7 @@ public class ChatClickEvent {
     private final String action;
     private final String value;
 
-    private ChatClickEvent(String action, String value) {
+    private ChatClickEvent(@NotNull String action, @NotNull String value) {
         this.action = action;
         this.value = value;
     }
@@ -19,7 +21,8 @@ public class ChatClickEvent {
      * @param url the URL to open
      * @return the chat click event
      */
-    public static ChatClickEvent openUrl(String url) {
+    @NotNull
+    public static ChatClickEvent openUrl(@NotNull String url) {
         return new ChatClickEvent("open_url", url);
     }
 
@@ -29,7 +32,8 @@ public class ChatClickEvent {
      * @param command the command to run
      * @return the chat click event
      */
-    public static ChatClickEvent runCommand(String command) {
+    @NotNull
+    public static ChatClickEvent runCommand(@NotNull String command) {
         return new ChatClickEvent("run_command", command);
     }
 
@@ -39,14 +43,17 @@ public class ChatClickEvent {
      * @param command the command to suggest
      * @return the chat click event
      */
-    public static ChatClickEvent suggestCommand(String command) {
+    @NotNull
+    public static ChatClickEvent suggestCommand(@NotNull String command) {
         return new ChatClickEvent("suggest_command", command);
     }
 
+    @NotNull
     protected String getAction() {
         return action;
     }
 
+    @NotNull
     protected String getValue() {
         return value;
     }
diff --git a/src/main/java/net/minestom/server/chat/ChatColor.java b/src/main/java/net/minestom/server/chat/ChatColor.java
index 90c2c00ef..e61c957c3 100644
--- a/src/main/java/net/minestom/server/chat/ChatColor.java
+++ b/src/main/java/net/minestom/server/chat/ChatColor.java
@@ -5,6 +5,8 @@ import it.unimi.dsi.fastutil.chars.Char2ObjectOpenHashMap;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import net.minestom.server.utils.validate.Check;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -148,6 +150,7 @@ public class ChatColor {
      * @param b the blue component
      * @return a chat color with the specified RGB color
      */
+    @NotNull
     public static ChatColor fromRGB(byte r, byte g, byte b) {
         return fromRGB(r, g, b, -1, null);
     }
@@ -162,6 +165,7 @@ public class ChatColor {
      * @param name the color name
      * @return the color associated with the name, {@link #NO_COLOR} if not found
      */
+    @NotNull
     public static ChatColor fromName(String name) {
         return colorCode.getOrDefault(name.toLowerCase(), NO_COLOR);
     }
@@ -172,6 +176,7 @@ public class ChatColor {
      * @param id the id of the color
      * @return the color associated with the id, {@link #NO_COLOR} if not found
      */
+    @NotNull
     public static ChatColor fromId(int id) {
         return idColorMap.getOrDefault(id, NO_COLOR);
     }
@@ -180,8 +185,9 @@ public class ChatColor {
      * Gets a color based on its legacy color code (eg: 1, 2, 3,... f).
      *
      * @param colorCode the color legacy code
-     * @return the color associated with the code
+     * @return the color associated with the code, {@link #NO_COLOR} if not found
      */
+    @NotNull
     public static ChatColor fromLegacyColorCodes(char colorCode) {
         return legacyColorCodesMap.getOrDefault(colorCode, NO_COLOR);
     }
@@ -227,10 +233,11 @@ public class ChatColor {
     }
 
     /**
-     * Gets the code name is the color is "special".
+     * Gets the code name if the color is "special".
      *
      * @return the special code name
      */
+    @Nullable
     protected String getCodeName() {
         return codeName;
     }
@@ -240,6 +247,7 @@ public class ChatColor {
         return id;
     }
 
+    @NotNull
     @Override
     public String toString() {
         if (empty)
diff --git a/src/main/java/net/minestom/server/chat/ChatHoverEvent.java b/src/main/java/net/minestom/server/chat/ChatHoverEvent.java
index 64a96b8fa..be292addf 100644
--- a/src/main/java/net/minestom/server/chat/ChatHoverEvent.java
+++ b/src/main/java/net/minestom/server/chat/ChatHoverEvent.java
@@ -3,6 +3,8 @@ package net.minestom.server.chat;
 import com.google.gson.JsonObject;
 import net.minestom.server.entity.Entity;
 import net.minestom.server.item.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 /**
@@ -15,26 +17,31 @@ public class ChatHoverEvent {
     private JsonObject valueObject;
     private final boolean isJson;
 
-    private ChatHoverEvent(String action, String value) {
+    private ChatHoverEvent(@NotNull String action, @NotNull String value) {
         this.action = action;
         this.value = value;
+        this.valueObject = null;
         this.isJson = false;
     }
 
-    private ChatHoverEvent(String action, JsonObject valueObject) {
+    private ChatHoverEvent(@NotNull String action, @NotNull JsonObject valueObject) {
         this.action = action;
+        this.value = null;
         this.valueObject = valueObject;
         this.isJson = true;
     }
 
+    @NotNull
     protected String getAction() {
         return action;
     }
 
+    @Nullable
     protected String getValue() {
         return value;
     }
 
+    @Nullable
     protected JsonObject getValueObject() {
         return valueObject;
     }
@@ -49,7 +56,8 @@ public class ChatHoverEvent {
      * @param text the text to show
      * @return the chat hover event
      */
-    public static ChatHoverEvent showText(ColoredText text) {
+    @NotNull
+    public static ChatHoverEvent showText(@NotNull ColoredText text) {
         return new ChatHoverEvent("show_text", text.getJsonObject());
     }
 
@@ -59,7 +67,8 @@ public class ChatHoverEvent {
      * @param text the text to show
      * @return the chat hover event
      */
-    public static ChatHoverEvent showText(String text) {
+    @NotNull
+    public static ChatHoverEvent showText(@NotNull String text) {
         return new ChatHoverEvent("show_text", text);
     }
 
@@ -69,7 +78,8 @@ public class ChatHoverEvent {
      * @param itemStack the item to show
      * @return the chat hover event
      */
-    public static ChatHoverEvent showItem(ItemStack itemStack) {
+    @NotNull
+    public static ChatHoverEvent showItem(@NotNull ItemStack itemStack) {
         final String json = itemStack.toNBT().toSNBT();
         return new ChatHoverEvent("show_item", json);
     }
@@ -80,7 +90,8 @@ public class ChatHoverEvent {
      * @param entity the entity to show
      * @return the chat hover event
      */
-    public static ChatHoverEvent showEntity(Entity entity) {
+    @NotNull
+    public static ChatHoverEvent showEntity(@NotNull Entity entity) {
         NBTCompound compound = new NBTCompound()
                 .setString("id", entity.getUuid().toString())
                 .setString("type", entity.getEntityType().getNamespaceID());
diff --git a/src/main/java/net/minestom/server/chat/ChatParser.java b/src/main/java/net/minestom/server/chat/ChatParser.java
index c985dd001..6211fd1e0 100644
--- a/src/main/java/net/minestom/server/chat/ChatParser.java
+++ b/src/main/java/net/minestom/server/chat/ChatParser.java
@@ -2,6 +2,7 @@ package net.minestom.server.chat;
 
 
 import com.google.gson.*;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Class used to convert JSON string to proper chat message representation.
@@ -16,7 +17,8 @@ public final class ChatParser {
      * @param json the json containing the text and color
      * @return a {@link ColoredText} representing the text
      */
-    public static ColoredText toColoredText(String json) {
+    @NotNull
+    public static ColoredText toColoredText(@NotNull String json) {
         StringBuilder builder = new StringBuilder();
 
         try {
@@ -40,7 +42,7 @@ public final class ChatParser {
         }
     }
 
-    private static void appendBuilder(StringBuilder builder, JsonObject object) {
+    private static void appendBuilder(@NotNull StringBuilder builder, @NotNull JsonObject object) {
         builder.append(parseText(object));
 
         final boolean hasExtra = object.has("extra");
@@ -59,7 +61,8 @@ public final class ChatParser {
      * @param textObject the text component to parse
      * @return the colored text format of the text component
      */
-    private static String parseText(JsonObject textObject) {
+    @NotNull
+    private static String parseText(@NotNull JsonObject textObject) {
         final boolean hasText = textObject.has("text");
         if (!hasText)
             return "";
@@ -80,7 +83,7 @@ public final class ChatParser {
         return builder.toString();
     }
 
-    private static void appendColor(JsonObject textObject, StringBuilder builder) {
+    private static void appendColor(@NotNull JsonObject textObject, @NotNull StringBuilder builder) {
         if (textObject.has("color")) {
             final String colorString = textObject.get("color").getAsString();
             if (colorString.startsWith("#")) {
@@ -94,7 +97,8 @@ public final class ChatParser {
         }
     }
 
-    private static void appendExtra(JsonObject textObject, StringBuilder builder, String name) {
+    private static void appendExtra(@NotNull JsonObject textObject, @NotNull StringBuilder builder,
+                                    @NotNull String name) {
         if (textObject.has(name)) {
             final boolean value = textObject.get(name).getAsBoolean();
             if (value) {
diff --git a/src/main/java/net/minestom/server/chat/TranslatableText.java b/src/main/java/net/minestom/server/chat/TranslatableText.java
index 82e41c030..9be8b7d37 100644
--- a/src/main/java/net/minestom/server/chat/TranslatableText.java
+++ b/src/main/java/net/minestom/server/chat/TranslatableText.java
@@ -1,5 +1,8 @@
 package net.minestom.server.chat;
 
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
 /**
  * Represents a translatable component which can be used in {@link ColoredText}.
  */
@@ -8,7 +11,7 @@ public class TranslatableText {
     private final String code;
     private final String[] arguments;
 
-    private TranslatableText(String code, String[] arguments) {
+    private TranslatableText(@NotNull String code, @Nullable String[] arguments) {
         this.code = code;
         this.arguments = arguments;
     }
@@ -19,7 +22,8 @@ public class TranslatableText {
      * @param code the translatable code
      * @return the translatable component linked to the code
      */
-    public static TranslatableText of(String code) {
+    @NotNull
+    public static TranslatableText of(@NotNull String code) {
         return new TranslatableText(code, null);
     }
 
@@ -30,7 +34,8 @@ public class TranslatableText {
      * @param arguments the translatable component arguments in order
      * @return the translatable component linked to the code and arguments
      */
-    public static TranslatableText of(String code, String... arguments) {
+    @NotNull
+    public static TranslatableText of(@NotNull String code, @NotNull String... arguments) {
         return new TranslatableText(code, arguments);
     }