diff --git a/src/strategies/call-block-logs/transformer.mjs b/src/strategies/call-block-logs/transformer.mjs
new file mode 100644
index 0000000..7a680eb
--- /dev/null
+++ b/src/strategies/call-block-logs/transformer.mjs
@@ -0,0 +1,35 @@
+// @format
+import { resolve } from "path";
+import { env } from "process";
+
+import logger from "../../logger.mjs";
+
+export const name = "call-block-logs";
+const log = logger(name);
+export const version = "0.1.0";
+
+const topics = [
+  "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
+];
+
+export function onClose() {
+  log("closed");
+  return {
+    write: null,
+    messages: [],
+  };
+}
+
+export function onError(error) {
+  log(error.toString());
+  throw error;
+}
+
+export function onLine(line) {
+  const logs = JSON.parse(line);
+  const filtered = logs.filter((log) => topics.includes(log.topics[0]));
+  return {
+    messages: [],
+    write: JSON.stringify(filtered),
+  };
+}