diff --git a/assembly/api.ts b/assembly/api.ts
index 6fed52b..af2b687 100644
--- a/assembly/api.ts
+++ b/assembly/api.ts
@@ -8,7 +8,6 @@ import { decodeProgram, liftBytes } from "./program";
 import { NO_OF_REGISTERS, REG_SIZE_BYTES, Registers } from "./registers";
 
 let interpreter: Interpreter | null = null;
-const builder = new MemoryBuilder();
 
 export function resetGeneric(program: u8[], flatRegisters: u8[], initialGas: Gas): void {
   const p = decodeProgram(liftBytes(program));
@@ -30,6 +29,7 @@ export function resetGenericWithMemory(
   const registers: Registers = new StaticArray(NO_OF_REGISTERS);
   fillRegisters(registers, flatRegisters);
 
+  const builder = new MemoryBuilder();
   const memory = buildMemory(builder, readPages(pageMap), readChunks(chunks));
 
   const int = new Interpreter(p, registers, memory);