diff --git a/futur-api/src/main/java/dev/tommyjs/futur/executor/PromiseExecutor.java b/futur-api/src/main/java/dev/tommyjs/futur/executor/PromiseExecutor.java
index a66d07f..1143ec2 100644
--- a/futur-api/src/main/java/dev/tommyjs/futur/executor/PromiseExecutor.java
+++ b/futur-api/src/main/java/dev/tommyjs/futur/executor/PromiseExecutor.java
@@ -6,6 +6,9 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * An executor that can run tasks and schedule tasks to run in the future.
+ */
 public interface PromiseExecutor<T> {
 
     /**
diff --git a/futur-api/src/main/java/dev/tommyjs/futur/promise/PromiseFactory.java b/futur-api/src/main/java/dev/tommyjs/futur/promise/PromiseFactory.java
index 0aac0c9..a651855 100644
--- a/futur-api/src/main/java/dev/tommyjs/futur/promise/PromiseFactory.java
+++ b/futur-api/src/main/java/dev/tommyjs/futur/promise/PromiseFactory.java
@@ -15,6 +15,9 @@ import java.util.function.Function;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
+/**
+ * A factory for creating and combining promises.
+ */
 @SuppressWarnings("unchecked")
 public interface PromiseFactory {