diff --git a/src/main/java/io/github/lonamiwebs/overgram/generator/Generator.java b/src/main/java/io/github/lonamiwebs/overgram/generator/Generator.java
index 4a1cda0..c5b0304 100644
--- a/src/main/java/io/github/lonamiwebs/overgram/generator/Generator.java
+++ b/src/main/java/io/github/lonamiwebs/overgram/generator/Generator.java
@@ -7,6 +7,9 @@ import java.io.*;
 import java.util.*;
 
 public class Generator {
+
+    private static final String VARIABLE_SUFFIX = "$";
+
     public static void generateJava(
             final List<TLObject> types, final List<TLObject> functions,
             final File abstractsFile, final File typesFile, final File functionsFile) throws IOException {
@@ -68,16 +71,13 @@ public class Generator {
                 writer.write(extendsName);
                 writer.write(" {\n");
 
-                int n = 0;
-                for (TLArg arg : object.args) {
-                    if (arg.flags) {
+                for (int i = 0; i < object.args.size(); ++i) {
+                    if (object.args.get(i).flags) {
                         continue;
                     }
-
                     writer.write("private ");
-                    writer.write(arg.javaType());
-                    writer.write(" var" + n);
-                    ++n;
+                    writer.write(object.args.get(i).javaType());
+                    writer.write(" " + VARIABLE_SUFFIX + i);
                     writer.write(";\n");
                 }
 
@@ -89,7 +89,7 @@ public class Generator {
                 // Objects will be created with nothing set and the arguments set with .argument(value).
                 // TODO
 
-                writer.write("public void serialize(final BinaryWriter writer) {}\n");
+                writeSerialize(writer, object);
                 writer.write("public void deserialize(final BinaryReader reader) {}\n");
 
                 writer.write("}\n");
@@ -101,6 +101,49 @@ public class Generator {
         writer.write("}\n");
     }
 
+    private static void writeSerialize(final Writer writer, final TLObject object) throws IOException {
+        writer.write("public void serialize(final BinaryWriter writer) {\n");
+        for (final TLArg arg : object.args) {
+            if (arg.flags) {
+                writer.write("int ");
+                writer.write(arg.name);
+                writer.write(" = 0;\n");
+            }
+        }
+        for (int i = 0; i < object.args.size(); ++i) {
+            final TLArg arg = object.args.get(i);
+            if (arg.flag != null) {
+                writer.write("if (" + VARIABLE_SUFFIX + i);
+                writer.write(arg.javaSetCheck());
+                writer.write(") { ");
+                writer.write(arg.flag.flagName);
+                writer.write(" |= " + (1 << arg.flag.flagIndex));
+                writer.write("; }\n");
+            }
+        }
+        for (int i = 0; i < object.args.size(); ++i) {
+            final TLArg arg = object.args.get(i);
+            if (arg.flag != null) {
+                writer.write("if (" + VARIABLE_SUFFIX + i);
+                writer.write(arg.javaSetCheck());
+                writer.write(") { ");
+            }
+            if (!arg.flags) {
+                writer.write("writer.write(" + VARIABLE_SUFFIX + i + ");");
+            } else {
+                writer.write("writer.write(");
+                writer.write(arg.name);
+                writer.write(");");
+            }
+            if (arg.flag != null) {
+                writer.write(" }\n");
+            } else {
+                writer.write('\n');
+            }
+        }
+        writer.write("}\n");
+    }
+
     private static Map<String, List<TLObject>> byNamespace(final Iterable<TLObject> objects) {
         final Map<String, List<TLObject>> result = new HashMap<>();
         for (final TLObject object : objects) {
diff --git a/src/main/java/io/github/lonamiwebs/overgram/parser/TLArg.java b/src/main/java/io/github/lonamiwebs/overgram/parser/TLArg.java
index a21e9dd..32d5061 100644
--- a/src/main/java/io/github/lonamiwebs/overgram/parser/TLArg.java
+++ b/src/main/java/io/github/lonamiwebs/overgram/parser/TLArg.java
@@ -61,7 +61,7 @@ public class TLArg {
                     }
                     break;
                 case "long":
-                // TODO handle int128 and int256 properly
+                    // TODO handle int128 and int256 properly
                 case "int128":
                 case "int256":
                     if (flag == null && !nested) {
@@ -110,6 +110,10 @@ public class TLArg {
         return builder.toString();
     }
 
+    public String javaSetCheck() {
+        return types.size() == 1 && types.get(0).equals("true") ? "" : " != null";
+    }
+
     @Override
     public String toString() {
         final StringBuilder builder = new StringBuilder();
@@ -134,9 +138,9 @@ public class TLArg {
         return builder.toString();
     }
 
-    private static final class Flag {
-        private final String flagName;
-        private final int flagIndex;
+    public static final class Flag {
+        public final String flagName;
+        public final int flagIndex;
 
         private Flag(final String flagName, final int flagIndex) {
             this.flagName = flagName;
diff --git a/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryWriter.java b/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryWriter.java
index d59b8db..3e9f8f7 100644
--- a/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryWriter.java
+++ b/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryWriter.java
@@ -1,5 +1,91 @@
 package io.github.lonamiwebs.overgram.utils;
 
 
+import io.github.lonamiwebs.overgram.tl.TLObject;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+
 public class BinaryWriter {
+    private final ByteBuffer buffer;
+
+    public BinaryWriter() {
+        buffer = ByteBuffer.allocate(128);
+        buffer.order(ByteOrder.LITTLE_ENDIAN);
+    }
+
+    public void write(final int value) {
+        buffer.putInt(value);
+    }
+
+    public void write(final long value) {
+        buffer.putLong(value);
+    }
+
+    public void write(final double value) {
+        buffer.putDouble(value);
+    }
+
+    public void write(final boolean value) {
+        buffer.putInt(value ? 0x997275b5 : 0xbc799737);
+    }
+
+    public void write(final byte[] bytes) {
+        int padding;
+        if (bytes.length < 254) {
+            padding = (bytes.length + 1) % 4;
+            buffer.put((byte) bytes.length);
+            buffer.put(bytes);
+        } else {
+            padding = bytes.length % 4;
+            buffer.putInt(bytes.length << 8 | 0xfe);
+            buffer.put(bytes);
+        }
+        if (padding != 0) {
+            for (padding = 4 - padding; padding-- != 0; ) {
+                buffer.put((byte) 0);
+            }
+        }
+    }
+
+    public void write(final String string) {
+        buffer.put(StandardCharsets.UTF_8.encode(string));
+    }
+
+    // TODO Handle boxed vs unboxed types (and vector<>)
+    public void write(final TLObject object) {
+        object.serialize(this);
+    }
+
+    @SuppressWarnings("unchecked")
+    public void write(final List<?> objects) {
+        write(0x1cb5c415);
+        write(objects.size());
+        if (objects.isEmpty()) {
+            return;
+        }
+
+        final Object first = objects.get(0);
+        if (first instanceof TLObject) {
+            for (final TLObject obj : (List<TLObject>) objects) {
+                write(obj);
+            }
+        } else if (first instanceof Integer) {
+            for (final Integer obj : (List<Integer>) objects) {
+                write(obj);
+            }
+        } else if (first instanceof Long) {
+            for (final Long obj : (List<Long>) objects) {
+                write(obj);
+            }
+        } else if (first instanceof byte[]) {
+            for (final byte[] obj : (List<byte[]>) objects) {
+                write(obj);
+            }
+        } else {
+            throw new UnsupportedOperationException();
+        }
+    }
 }