diff --git a/src/main/java/de/maishai/ast/Node.java b/src/main/java/de/maishai/ast/Node.java
index b07e221..250bab9 100644
--- a/src/main/java/de/maishai/ast/Node.java
+++ b/src/main/java/de/maishai/ast/Node.java
@@ -1,4 +1,11 @@
 package de.maishai.ast;
 
+import de.maishai.typedast.Type;
+import de.maishai.ast.records.Class;
+import java.util.Map;
+
 public interface Node {
+
+   public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes);
+
 }
diff --git a/src/main/java/de/maishai/ast/Statement.java b/src/main/java/de/maishai/ast/Statement.java
index c9e690c..2d38f50 100644
--- a/src/main/java/de/maishai/ast/Statement.java
+++ b/src/main/java/de/maishai/ast/Statement.java
@@ -1,3 +1,4 @@
 package de.maishai.ast;
 public interface Statement extends Node  {
+    
 }
diff --git a/src/main/java/de/maishai/ast/Type.java b/src/main/java/de/maishai/ast/Type.java
deleted file mode 100644
index 8e1f050..0000000
--- a/src/main/java/de/maishai/ast/Type.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package de.maishai.ast;
-
-public enum Type {
-    INT,
-    BOOL,
-    CHAR
-}
diff --git a/src/main/java/de/maishai/ast/records/Assignment.java b/src/main/java/de/maishai/ast/records/Assignment.java
index a5c596b..33d5f14 100644
--- a/src/main/java/de/maishai/ast/records/Assignment.java
+++ b/src/main/java/de/maishai/ast/records/Assignment.java
@@ -3,6 +3,20 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Expression;
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record Assignment(Id loc, Expression value) implements Statement, Expression {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+
+        if (localVars.get(loc.name()) == null) {
+            throw new RuntimeException("Variable " + loc.name() + " not declared");
+        }
+        if (!localVars.get(loc.name()).equals(value.typeCheck(localVars, classes))) {
+            throw new RuntimeException("Type mismatch in assignment to " + loc.name());
+        }
+        return loc.typeCheck(localVars, classes);
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Binary.java b/src/main/java/de/maishai/ast/records/Binary.java
index 40070e3..e1fe1f2 100644
--- a/src/main/java/de/maishai/ast/records/Binary.java
+++ b/src/main/java/de/maishai/ast/records/Binary.java
@@ -3,6 +3,17 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Expression;
 import de.maishai.ast.Operator;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record Binary(Expression left, Operator op, Expression right) implements Expression {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        // x = y + z -> y, z : int
+       if(left.typeCheck(localVars, classes) != Type.INT && right.typeCheck(localVars, classes) != Type.INT) {
+           throw new RuntimeException("Binary operation on non-integers");
+       }
+       return Type.INT;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Block.java b/src/main/java/de/maishai/ast/records/Block.java
index e36affe..eb0f6ef 100644
--- a/src/main/java/de/maishai/ast/records/Block.java
+++ b/src/main/java/de/maishai/ast/records/Block.java
@@ -4,8 +4,23 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Node;
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
 
 import java.util.List;
+import java.util.Map;
 
 public record Block(List<Variable> vars, List<Statement> stmts) implements Node {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        // Add the variables to the local variables
+        for (Variable var : vars) {
+            localVars.put(var.name(), var.type());
+        }
+        // Type check the statements
+        for (Statement stmt : stmts) {
+            stmt.typeCheck(localVars, classes);
+        }
+        // Return the type of the last statement
+        return stmts.get(stmts.size() - 1).typeCheck(localVars, classes);
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/BoolConstant.java b/src/main/java/de/maishai/ast/records/BoolConstant.java
index 3b6e0a9..e9f4014 100644
--- a/src/main/java/de/maishai/ast/records/BoolConstant.java
+++ b/src/main/java/de/maishai/ast/records/BoolConstant.java
@@ -2,6 +2,13 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Expression;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record BoolConstant(Boolean value) implements Expression {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return Type.BOOL;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Break.java b/src/main/java/de/maishai/ast/records/Break.java
index 9e9dc87..dfa3add 100644
--- a/src/main/java/de/maishai/ast/records/Break.java
+++ b/src/main/java/de/maishai/ast/records/Break.java
@@ -2,6 +2,13 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record Break() implements Statement {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return Type.VOID;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/CharConstant.java b/src/main/java/de/maishai/ast/records/CharConstant.java
index fdf4ec6..ea87871 100644
--- a/src/main/java/de/maishai/ast/records/CharConstant.java
+++ b/src/main/java/de/maishai/ast/records/CharConstant.java
@@ -2,6 +2,13 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Expression;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record CharConstant(char value) implements Expression {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return Type.CHAR;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Class.java b/src/main/java/de/maishai/ast/records/Class.java
index 203a48e..bd80e23 100644
--- a/src/main/java/de/maishai/ast/records/Class.java
+++ b/src/main/java/de/maishai/ast/records/Class.java
@@ -1,8 +1,25 @@
 package de.maishai.ast.records;
 
 import de.maishai.ast.Node;
+import de.maishai.typedast.Type;
 
 import java.util.List;
+import java.util.Map;
 
 public record Class(Id id ,List<Variable> variables, List<Method> methods) implements Node {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        if(classes.containsKey(id.name())) {
+            throw new RuntimeException("Class " + id.name() + " already declared");
+        }
+        classes.put(id.name(), this);
+        for(Variable variable : variables) {
+            variable.typeCheck(localVars, classes);
+        }
+        for(Method method : methods) {
+            method.typeCheck(localVars, classes);
+        }
+
+        return Type.VOID;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Continue.java b/src/main/java/de/maishai/ast/records/Continue.java
index 29b7382..2f9141c 100644
--- a/src/main/java/de/maishai/ast/records/Continue.java
+++ b/src/main/java/de/maishai/ast/records/Continue.java
@@ -2,6 +2,13 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record Continue() implements Statement {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return Type.VOID;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/For.java b/src/main/java/de/maishai/ast/records/For.java
index 2440947..0e1aea1 100644
--- a/src/main/java/de/maishai/ast/records/For.java
+++ b/src/main/java/de/maishai/ast/records/For.java
@@ -3,6 +3,21 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Expression;
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record For(Expression assign, Expression cond, Expression inc, Block block) implements Statement {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        // like int i = 0
+        assign.typeCheck(localVars, classes);
+        // like i < 10 -> bool
+        if (cond.typeCheck(localVars, classes) != Type.BOOL) {
+            throw new RuntimeException("Condition must be of type bool");
+        }
+        // like i++
+        inc.typeCheck(localVars, classes);
+        return block.typeCheck(localVars, classes);
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Id.java b/src/main/java/de/maishai/ast/records/Id.java
index 5e5f3ea..57599fa 100644
--- a/src/main/java/de/maishai/ast/records/Id.java
+++ b/src/main/java/de/maishai/ast/records/Id.java
@@ -2,6 +2,16 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Expression;
+import de.maishai.typedast.Type;
 
-public record Id(String name) implements Expression {
-}
+import java.util.Map;
+
+    public record Id(String name) implements Expression {
+        @Override
+        public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+            if(!localVars.containsKey(name)) {
+                throw new RuntimeException("Variable " + name + " not declared");
+            }
+            return localVars.get(name);
+        }
+    }
diff --git a/src/main/java/de/maishai/ast/records/IfElse.java b/src/main/java/de/maishai/ast/records/IfElse.java
index 50c355b..e867f11 100644
--- a/src/main/java/de/maishai/ast/records/IfElse.java
+++ b/src/main/java/de/maishai/ast/records/IfElse.java
@@ -2,5 +2,21 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Expression;
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
+
 public record IfElse(Expression cond, Block ifBlock, Block elseBlock) implements Statement {
+
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+
+        // Con must be type bool and both blocks must have the same type
+        if(cond.typeCheck(localVars, classes).equals(Type.BOOL)
+            && ifBlock.typeCheck(localVars, classes).equals(elseBlock.typeCheck(localVars, classes))) {
+            return ifBlock.typeCheck(localVars, classes);
+        }
+
+        throw new RuntimeException("IfElse statement type check failed");
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/IntConstant.java b/src/main/java/de/maishai/ast/records/IntConstant.java
index 79c1ea7..c049b94 100644
--- a/src/main/java/de/maishai/ast/records/IntConstant.java
+++ b/src/main/java/de/maishai/ast/records/IntConstant.java
@@ -2,6 +2,13 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Expression;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record IntConstant(Integer value) implements Expression {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return Type.INT;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/MainMethod.java b/src/main/java/de/maishai/ast/records/MainMethod.java
index 0da1915..bbb5335 100644
--- a/src/main/java/de/maishai/ast/records/MainMethod.java
+++ b/src/main/java/de/maishai/ast/records/MainMethod.java
@@ -4,8 +4,15 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Node;
 import de.maishai.ast.ReturnType;
+import de.maishai.typedast.Type;
 
 import java.util.List;
+import java.util.Map;
 
 public record MainMethod(ReturnType type, Id id, List<Parameter> params, Block block) implements Node {
+
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return null;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Method.java b/src/main/java/de/maishai/ast/records/Method.java
index 742bb54..7bfb8f6 100644
--- a/src/main/java/de/maishai/ast/records/Method.java
+++ b/src/main/java/de/maishai/ast/records/Method.java
@@ -1,11 +1,32 @@
 package de.maishai.ast.records;
 
 
-
 import de.maishai.ast.Node;
 import de.maishai.ast.ReturnType;
+import de.maishai.typedast.Type;
 
 import java.util.List;
+import java.util.Map;
 
-public record Method(ReturnType type, Id id, List<Parameter> params, Block block) implements Node {
+public record Method(Type type, Id id, List<Parameter> params, Block block) implements Node {
+
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        if (localVars.containsKey(id.name())) {
+            throw new RuntimeException("Variable " + id.name() + " already declared");
+        }
+        localVars.put(id.name(), type);
+
+        for (Parameter parameter : params) {
+            parameter.typeCheck(localVars, classes);
+        }
+
+        Type returnType = block.typeCheck(localVars, classes);
+        if (!returnType.equals(type)) {
+            throw new RuntimeException("Return type mismatch");
+        }
+        
+        return returnType;
+
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/MethodCall.java b/src/main/java/de/maishai/ast/records/MethodCall.java
index 2f84949..265b356 100644
--- a/src/main/java/de/maishai/ast/records/MethodCall.java
+++ b/src/main/java/de/maishai/ast/records/MethodCall.java
@@ -4,8 +4,49 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Expression;
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
 
 import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+public record MethodCall(Optional<String> receiver, String name, List<Expression> args) implements Expression, Statement {
+
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        Type returnType = null;
+
+        if(receiver.isPresent()) {
+            // check if receiver is a local variable
+             if(!localVars.containsKey(receiver.get())){
+                 throw new RuntimeException("Variable " + receiver.get() + " not found");
+            }
+        }
+
+        // check if method exists in class
+        if(localVars.get(name) == null) {
+            throw new RuntimeException("Variable " + name + " not found");
+        }
+
+        Type type = localVars.get(name);
+        Class class1 = classes.get(type.name());
+        if(class1 == null) {
+            throw new RuntimeException("Class " + type + " not found");
+        }
+        for(Method method : class1.methods()){
+            if(method.id().name().equals(name)){
+                for(int i = 0; i < method.params().size(); i++){
+                    if(!method.params().get(i).type().equals(args.get(i).typeCheck(localVars, classes))){
+                        throw new RuntimeException("Type mismatch in method call " + name);
+                    }
+                }
+                returnType = method.type();
+                break;
+            }else{
+                throw new RuntimeException("Method " + name + " not found in class " + type);
+            }
+        }
+        return returnType;
+    }
 
-public record MethodCall(String name, List<Expression> args) implements Expression, Statement {
 }
diff --git a/src/main/java/de/maishai/ast/records/New.java b/src/main/java/de/maishai/ast/records/New.java
index 347fb7d..2acece2 100644
--- a/src/main/java/de/maishai/ast/records/New.java
+++ b/src/main/java/de/maishai/ast/records/New.java
@@ -1,12 +1,18 @@
 package de.maishai.ast.records;
 
 
-
 import de.maishai.ast.Expression;
+
 import de.maishai.ast.Statement;
-import de.maishai.ast.Type;
+import de.maishai.typedast.Type;
 
 import java.util.List;
+import java.util.Map;
 
 public record New(Type type, List<Expression> args) implements Expression, Statement {
+
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return type;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Parameter.java b/src/main/java/de/maishai/ast/records/Parameter.java
index 508ef1e..8952fcd 100644
--- a/src/main/java/de/maishai/ast/records/Parameter.java
+++ b/src/main/java/de/maishai/ast/records/Parameter.java
@@ -2,7 +2,18 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Node;
-import de.maishai.ast.Type;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record Parameter(String name, Type type) implements Node {
+
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        if (localVars.containsKey(name)) {
+            throw new RuntimeException("Variable " + name + " already declared");
+        }
+        localVars.put(name, type);
+        return type;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Program.java b/src/main/java/de/maishai/ast/records/Program.java
index ec638c0..6952d2e 100644
--- a/src/main/java/de/maishai/ast/records/Program.java
+++ b/src/main/java/de/maishai/ast/records/Program.java
@@ -2,8 +2,14 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Node;
+import de.maishai.typedast.Type;
 
 import java.util.List;
+import java.util.Map;
 
 public record Program(List<Class> variables) implements Node {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return null;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Return.java b/src/main/java/de/maishai/ast/records/Return.java
index 5e3e0bd..4e8330e 100644
--- a/src/main/java/de/maishai/ast/records/Return.java
+++ b/src/main/java/de/maishai/ast/records/Return.java
@@ -3,6 +3,15 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Expression;
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
+
 
 public record Return(Expression ret) implements Statement {
+
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return ret.typeCheck(localVars, classes);
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/ReturnVoid.java b/src/main/java/de/maishai/ast/records/ReturnVoid.java
index 7100004..1b2d662 100644
--- a/src/main/java/de/maishai/ast/records/ReturnVoid.java
+++ b/src/main/java/de/maishai/ast/records/ReturnVoid.java
@@ -2,6 +2,14 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
 
+import java.util.Map;
+
+// Why does ReturnVoid not have statements
 public record ReturnVoid() implements Statement {
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        return Type.VOID;
+    }
 }
diff --git a/src/main/java/de/maishai/ast/records/Variable.java b/src/main/java/de/maishai/ast/records/Variable.java
index 1f2901c..791b339 100644
--- a/src/main/java/de/maishai/ast/records/Variable.java
+++ b/src/main/java/de/maishai/ast/records/Variable.java
@@ -2,7 +2,18 @@ package de.maishai.ast.records;
 
 
 import de.maishai.ast.Node;
-import de.maishai.ast.Type;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record Variable(String name, Type type) implements Node {
+
+        @Override
+        public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+            if (localVars.containsKey(name)) {
+                throw new RuntimeException("Variable " + name + " already declared");
+            }
+            localVars.put(name, type);
+            return type;
+        }
 }
diff --git a/src/main/java/de/maishai/ast/records/While.java b/src/main/java/de/maishai/ast/records/While.java
index 47b7548..d48c6f2 100644
--- a/src/main/java/de/maishai/ast/records/While.java
+++ b/src/main/java/de/maishai/ast/records/While.java
@@ -3,6 +3,19 @@ package de.maishai.ast.records;
 
 import de.maishai.ast.Expression;
 import de.maishai.ast.Statement;
+import de.maishai.typedast.Type;
+
+import java.util.Map;
 
 public record While(Expression cond, Block block) implements Statement {
+
+
+    @Override
+    public Type typeCheck(Map<String, Type> localVars, Map<String, Class> classes) {
+        Type condType = cond.typeCheck(localVars, classes);
+        if (condType != Type.BOOL) {
+            throw new RuntimeException("Condition must be of type bool");
+        }
+        return block.typeCheck(localVars, classes);
+    }
 }