diff --git a/api/src/main/java/me/filoghost/holographicdisplays/api/HolographicDisplaysAPI.java b/api/src/main/java/me/filoghost/holographicdisplays/api/HolographicDisplaysAPI.java
index 03d97f02..6c90b0b7 100644
--- a/api/src/main/java/me/filoghost/holographicdisplays/api/HolographicDisplaysAPI.java
+++ b/api/src/main/java/me/filoghost/holographicdisplays/api/HolographicDisplaysAPI.java
@@ -192,6 +192,7 @@ public interface HolographicDisplaysAPI {
      * Returns if a placeholder with a given identifier is registered.
      *
      * @param identifier the case-insensitive identifier of the placeholder
+     * @return if the given placeholder identifier exists
      * @since 1
      */
     boolean isRegisteredPlaceholder(@NotNull String identifier);
diff --git a/api/src/main/java/me/filoghost/holographicdisplays/api/Position.java b/api/src/main/java/me/filoghost/holographicdisplays/api/Position.java
index a5411fb9..3de96611 100644
--- a/api/src/main/java/me/filoghost/holographicdisplays/api/Position.java
+++ b/api/src/main/java/me/filoghost/holographicdisplays/api/Position.java
@@ -199,6 +199,7 @@ public interface Position {
      * @param x the length to add to the X coordinate
      * @param y the length to add to the Y coordinate
      * @param z the length to add to the Z coordinate
+     * @return the new position
      * @since 1
      */
     @NotNull Position add(double x, double y, double z);
@@ -209,6 +210,7 @@ public interface Position {
      * @param x the length to subtract from the X coordinate
      * @param y the length to subtract from the Y coordinate
      * @param z the length to subtract from the Z coordinate
+     * @return the new position
      * @since 1
      */
     @NotNull Position subtract(double x, double y, double z);
diff --git a/api/src/main/java/me/filoghost/holographicdisplays/api/hologram/VisibilitySettings.java b/api/src/main/java/me/filoghost/holographicdisplays/api/hologram/VisibilitySettings.java
index 2b21a834..66497104 100644
--- a/api/src/main/java/me/filoghost/holographicdisplays/api/hologram/VisibilitySettings.java
+++ b/api/src/main/java/me/filoghost/holographicdisplays/api/hologram/VisibilitySettings.java
@@ -41,6 +41,8 @@ public interface VisibilitySettings {
      * ({@link #getGlobalVisibility()}). The individual visibility value can be removed with
      * {@link #removeIndividualVisibility(Player)}.
      *
+     * @param player the player for which to set the individual visibility
+     * @param visibility the new individual visibility to use for the player
      * @since 1
      */
     void setIndividualVisibility(@NotNull Player player, @NotNull Visibility visibility);
@@ -49,6 +51,7 @@ public interface VisibilitySettings {
      * Removes the individual visibility for a player. The visibility for the player will then be determined by the
      * global visibility ({@link #getGlobalVisibility()}).
      *
+     * @param player the player for which to remove the individual visibility
      * @since 1
      */
     void removeIndividualVisibility(@NotNull Player player);
@@ -65,7 +68,7 @@ public interface VisibilitySettings {
      * Checks if a hologram is visible to a player, taking into account both the global visibility and the individual
      * visibility for the player (if set).
      *
-     * @param player the player
+     * @param player the player for which to check the visibility
      * @return if the player can see the hologram
      * @since 1
      */
diff --git a/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/GlobalPlaceholderReplaceFunction.java b/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/GlobalPlaceholderReplaceFunction.java
index af502dc6..9b9173ce 100644
--- a/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/GlobalPlaceholderReplaceFunction.java
+++ b/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/GlobalPlaceholderReplaceFunction.java
@@ -22,6 +22,8 @@ public interface GlobalPlaceholderReplaceFunction {
     /**
      * Same as {@link GlobalPlaceholder#getReplacement(String)}.
      *
+     * @param argument the optional placeholder argument, null if not specified
+     * @return the optional placeholder replacement, null to leave the placeholder unreplaced
      * @since 1
      */
     @Nullable String getReplacement(@Nullable String argument);
diff --git a/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/IndividualPlaceholderReplaceFunction.java b/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/IndividualPlaceholderReplaceFunction.java
index c9f7d2ad..2bcdd6a5 100644
--- a/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/IndividualPlaceholderReplaceFunction.java
+++ b/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/IndividualPlaceholderReplaceFunction.java
@@ -24,6 +24,9 @@ public interface IndividualPlaceholderReplaceFunction {
     /**
      * Same as {@link IndividualPlaceholder#getReplacement(Player, String)}.
      *
+     * @param player the player that will see the provided replacement
+     * @param argument the optional placeholder argument, null if not specified
+     * @return the optional placeholder replacement, null to leave the placeholder unreplaced
      * @since 1
      */
     @Nullable String getReplacement(@NotNull Player player, @Nullable String argument);
diff --git a/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/Placeholder.java b/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/Placeholder.java
index 35151454..676af2e5 100644
--- a/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/Placeholder.java
+++ b/api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/Placeholder.java
@@ -49,6 +49,7 @@ public interface Placeholder {
      * Note that more ticks can pass between invocations if no player is near, do not use the replacement callback as a
      * timer.
      *
+     * @return the refresh interval in ticks
      * @since 1
      */
     int getRefreshIntervalTicks();