diff --git a/effekt/shared/src/main/scala/effekt/core/ArityRaising.scala b/effekt/shared/src/main/scala/effekt/core/ArityRaising.scala
new file mode 100644
index 000000000..0540d732b
--- /dev/null
+++ b/effekt/shared/src/main/scala/effekt/core/ArityRaising.scala
@@ -0,0 +1,87 @@
+package effekt
+package core
+import effekt.context.Context
+import effekt.core.optimizer.Deadcode
+import effekt.typer.Typer.checkMain
+
+object ArityRaising extends Phase[CoreTransformed, CoreTransformed] {
+  override val phaseName: String = "arity raising"
+
+
+  override def run(input: CoreTransformed)(using C: Context): Option[CoreTransformed] = input match {
+    case CoreTransformed(source, tree, mod, core) => {
+      implicit val pctx: DeclarationContext = new DeclarationContext(core.declarations, core.externs)
+      Context.module = mod
+      val main = C.ensureMainExists(mod)
+      val res = Deadcode.remove(main, core)
+      val transformed = Context.timed(phaseName, source.name) { transform(res) }
+      println(PrettyPrinter.format(transformed))
+      Some(CoreTransformed(source, tree, mod, transformed))
+    }
+  }
+
+  def transform(decl: ModuleDecl)(using Context, DeclarationContext): ModuleDecl = decl match {
+    case ModuleDecl(path, includes, declarations, externs, definitions, exports) =>
+      ModuleDecl(path, includes, declarations, externs, definitions map transform, exports)
+  }
+
+  def transform(toplevel: Toplevel)(using Context, DeclarationContext): Toplevel = toplevel match {
+    case Toplevel.Def(id, block) => Toplevel.Def(id, transform(block))
+    case Toplevel.Val(id, tpe, binding) => Toplevel.Val(id, tpe, transform(binding))
+  }
+
+  def transform(block: Block.BlockLit)(using Context, DeclarationContext): Block.BlockLit = block match {
+    case Block.BlockLit(tparams, cparams, vparams, bparams, body) =>
+      Block.BlockLit(tparams, cparams, vparams, bparams, transform(body))
+  }
+  
+  def transform(block: Block)(using Context, DeclarationContext): Block = block match {
+    case Block.BlockVar(id, annotatedTpe, annotatedCapt) => block
+    case b: Block.BlockLit => transform(b)
+    case Block.Unbox(pure) => Block.Unbox(transform(pure))
+    case Block.New(impl) => block
+  }
+
+  def transform(stmt: Stmt)(using Context, DeclarationContext): Stmt = stmt match {
+    case Stmt.Def(id, block, rest) =>
+      Stmt.Def(id, transform(block), transform(rest))
+    case Stmt.Let(id, tpe, binding, rest) =>
+      Stmt.Let(id, tpe, transform(binding), transform(rest))
+    case Stmt.Return(expr) =>
+      Stmt.Return(transform(expr))
+    case Stmt.Val(id, tpe, binding, body) =>
+      Stmt.Val(id, tpe, transform(binding), transform(body))
+    case Stmt.App(callee, targs, vargs, bargs) =>
+      Stmt.App(transform(callee), targs, vargs map transform, bargs map transform) // possible args
+    case Stmt.Invoke(callee, method, methodTpe, targs, vargs, bargs) =>
+      Stmt.Invoke(transform(callee), method, methodTpe, targs, vargs map transform, bargs map transform) // possible args
+    case Stmt.If(cond, thn, els) =>
+      Stmt.If(transform(cond), transform(thn), transform(els))
+    case Stmt.Match(scrutinee, clauses, default) =>
+      Stmt.Match(transform(scrutinee), clauses.map { case (id, clause) => (id, transform(clause)) }, default map transform)
+    case _ => stmt
+  }
+
+  def transform(expr: Expr)(using Context, DeclarationContext): Expr = expr match {
+    case DirectApp(b, targs, vargs, bargs) =>
+      DirectApp(b, targs, vargs map transform, bargs map transform) // possible args
+    case pure: Pure =>
+      transform(pure)
+  }
+
+  def transform(pure: Pure)(using Context, DeclarationContext): Pure = pure match {
+    case Pure.ValueVar(id, annotatedType) => pure
+    case Pure.Literal(value, annotatedType) => pure
+    case Pure.Box(b, annotatedCapture) => pure
+    case Pure.PureApp(b, targs, vargs) =>
+      Pure.PureApp(b, targs, vargs map transform) // possible args
+    case Pure.Make(data, tag, targs, vargs) =>
+      Pure.Make(data, tag, targs, vargs map transform) // possibe args
+      
+  }
+
+  def transform(valueType: ValueType.Data)(using Context, DeclarationContext): ValueType.Data = valueType match {
+    case ValueType.Data(symbol, targs) => valueType // trainsform
+  }
+
+}
\ No newline at end of file
diff --git a/effekt/shared/src/main/scala/effekt/generator/js/JavaScript.scala b/effekt/shared/src/main/scala/effekt/generator/js/JavaScript.scala
index a79cdb12f..378025c07 100644
--- a/effekt/shared/src/main/scala/effekt/generator/js/JavaScript.scala
+++ b/effekt/shared/src/main/scala/effekt/generator/js/JavaScript.scala
@@ -7,6 +7,7 @@ import effekt.context.Context
 import effekt.core.optimizer.{ DropBindings, Optimizer }
 import kiama.output.PrettyPrinterTypes.Document
 import kiama.util.Source
+import effekt.core.ArityRaising
 
 
 class JavaScript(additionalFeatureFlags: List[String] = Nil) extends Compiler[String] {
@@ -42,7 +43,7 @@ class JavaScript(additionalFeatureFlags: List[String] = Nil) extends Compiler[St
     Frontend andThen Middleend
   }
 
-  lazy val Optimized = allToCore(Core) andThen Aggregate andThen Optimizer andThen DropBindings map {
+  lazy val Optimized = allToCore(Core) andThen Aggregate andThen ArityRaising andThen Optimizer andThen DropBindings map {
     case input @ CoreTransformed(source, tree, mod, core) =>
       val mainSymbol = Context.ensureMainExists(mod)
       val mainFile = path(mod)