diff --git a/core/src/com/riiablo/io/ByteInput.java b/core/src/com/riiablo/io/ByteInput.java
index 8cb8df21..f073b1cb 100644
--- a/core/src/com/riiablo/io/ByteInput.java
+++ b/core/src/com/riiablo/io/ByteInput.java
@@ -217,6 +217,7 @@ public class ByteInput {
    * @see ByteBuf#readSlice(int)
    */
   public ByteInput readSlice(long numBytes) {
+    assert aligned() : "not aligned";
     assert numBytes <= Integer.MAX_VALUE : "ByteBuf only supports int length";
     final int mark = updateMark(); // updates mark to start offset of slice
     final ByteBuf slice = buffer.readSlice((int) numBytes);
diff --git a/core/src/com/riiablo/io/ByteOutput.java b/core/src/com/riiablo/io/ByteOutput.java
index 08b5ced7..60c8ccc5 100644
--- a/core/src/com/riiablo/io/ByteOutput.java
+++ b/core/src/com/riiablo/io/ByteOutput.java
@@ -51,6 +51,7 @@ public class ByteOutput {
   }
 
   public ByteOutput skipBytes(int bytes) {
+    assert aligned() : "not aligned";
     incrementBitsWritten((long) bytes * Byte.SIZE);
     buffer.writeZero(bytes);
     return this;
@@ -108,6 +109,7 @@ public class ByteOutput {
   }
 
   public ByteOutput writeString(CharSequence chars) {
+    assert aligned() : "not aligned";
     incrementBitsWritten((long) chars.length() * Byte.SIZE);
     buffer.writeCharSequence(chars, CharsetUtil.US_ASCII);
     return this;