diff --git a/src/evt_core.c b/src/evt_core.c
index 498679e..064ce0a 100644
--- a/src/evt_core.c
+++ b/src/evt_core.c
@@ -65,7 +65,7 @@ void evt_core_add_cat(struct evt_core_ctx* ctx, struct evt_core_cat* cat) {
 }
 
 void evt_core_mv_fd(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, struct evt_core_cat* to_cat) {
-  if (ctx->verbose) printf("Moving fd=%d from cat=%s to cat=%s\n",fdinfo->fd, fdinfo->cat->name, to_cat->name);
+  if (ctx->verbose) fprintf(stderr, "Moving fd=%d from cat=%s to cat=%s\n",fdinfo->fd, fdinfo->cat->name, to_cat->name);
 
   // 1. Update old category
   for (int i = 0; i < fdinfo->cat->socklist->len; i++) {
@@ -130,7 +130,7 @@ struct evt_core_fdinfo* evt_core_add_fd(struct evt_core_ctx* ctx, struct evt_cor
 
   // 5. Add file descriptor to epoll
   add_fd_to_epoll(ctx->epollfd, user_data->fd, cat->flags);
-  if (ctx->verbose) printf("Added fd=%d with url=%s in cat=%s\n", fdinfo->fd, fdinfo->url, fdinfo->cat->name);
+  if (ctx->verbose) fprintf(stderr, "Added fd=%d with url=%s in cat=%s\n", fdinfo->fd, fdinfo->url, fdinfo->cat->name);
 
   // 6. Ensure that events arrived before epoll registering are handled
   fdinfo->cat->cb(ctx, fdinfo);
@@ -145,7 +145,7 @@ struct evt_core_cat* evt_core_rm_fd(struct evt_core_ctx* ctx, int fd) {
   struct evt_core_fdinfo* fdinfo = g_hash_table_lookup (ctx->socklist, &fd);
   if (fdinfo == NULL) return NULL;
   cat = fdinfo->cat;
-  if (ctx->verbose) printf("Closing fd=%d from cat=%s\n",fdinfo->fd, fdinfo->cat->name);
+  if (ctx->verbose) fprintf(stderr, "Closing fd=%d from cat=%s\n",fdinfo->fd, fdinfo->cat->name);
 
   // 2. Update category
   for (int i = 0; i < cat->socklist->len; i++) {
@@ -238,7 +238,7 @@ void evt_core_loop(struct evt_core_ctx* ctx) {
       if (ctx->verbose) {
         end = clock();
         elapsed_in_cb = ((double) (end - start)) / CLOCKS_PER_SEC;
-        printf("%s cb took %f seconds to execute.\n", fdinfo->url, elapsed_in_cb);
+        fprintf(stderr, "%s cb took %f seconds to execute.\n", fdinfo->url, elapsed_in_cb);
       }
     }
   }