diff --git a/.changeset/many-rockets-marry.md b/.changeset/many-rockets-marry.md
new file mode 100644
index 0000000000..896eb5ea7e
--- /dev/null
+++ b/.changeset/many-rockets-marry.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-techdocs-backend': patch
+---
+
+Minor type fix
diff --git a/plugins/techdocs-backend/src/cache/cacheMiddleware.ts b/plugins/techdocs-backend/src/cache/cacheMiddleware.ts
index 02b35cf7bf..78660d3c39 100644
--- a/plugins/techdocs-backend/src/cache/cacheMiddleware.ts
+++ b/plugins/techdocs-backend/src/cache/cacheMiddleware.ts
@@ -58,7 +58,11 @@ export const createCacheMiddleware = ({
       encoding?: BufferEncoding | ErrorCallback,
       callback?: ErrorCallback,
     ) => {
-      chunks.push(Buffer.from(data));
+      // This cast is obviously weird, but it covers a type bug in @types/node
+      // which does not gracefully handle union types.
+      chunks.push(
+        typeof data === 'string' ? Buffer.from(data) : Buffer.from(data),
+      );
       if (typeof encoding === 'function') {
         return realWrite(data, encoding);
       }