diff --git a/include/fluent-bit/flb_io.h b/include/fluent-bit/flb_io.h
index 559bc95d7b2..7c553a5e2ed 100644
--- a/include/fluent-bit/flb_io.h
+++ b/include/fluent-bit/flb_io.h
@@ -48,5 +48,7 @@ int flb_io_net_connect(struct flb_upstream_conn *u_conn,
 int flb_io_net_write(struct flb_upstream_conn *u, const void *data,
                      size_t len, size_t *out_len);
 ssize_t flb_io_net_read(struct flb_upstream_conn *u, void *buf, size_t len);
+int flb_io_fd_write(int fd, const void *data, size_t len, size_t *out_len);
+ssize_t flb_io_fd_read(int fd, void *buf, size_t len);
 
 #endif
diff --git a/src/flb_io.c b/src/flb_io.c
index 0905843f2b3..1e0872f5f2b 100644
--- a/src/flb_io.c
+++ b/src/flb_io.c
@@ -118,12 +118,11 @@ int flb_io_net_connect(struct flb_upstream_conn *u_conn,
     return 0;
 }
 
+static int fd_io_write(int fd, const void *data, size_t len, size_t *out_len);
 static int net_io_write(struct flb_upstream_conn *u_conn,
                         const void *data, size_t len, size_t *out_len)
 {
     int ret;
-    int tries = 0;
-    size_t total = 0;
     struct flb_coro *coro;
 
     if (u_conn->fd <= 0) {
@@ -134,8 +133,17 @@ static int net_io_write(struct flb_upstream_conn *u_conn,
         }
     }
 
+    return fd_io_write(u_conn->fd, data, len, out_len);
+}
+
+static int fd_io_write(int fd, const void *data, size_t len, size_t *out_len)
+{
+    int ret;
+    int tries = 0;
+    size_t total = 0;
+
     while (total < len) {
-        ret = send(u_conn->fd, (char *) data + total, len - total, 0);
+        ret = send(fd, (char *) data + total, len - total, 0);
         if (ret == -1) {
             if (FLB_WOULDBLOCK()) {
                 /*
@@ -305,12 +313,18 @@ static FLB_INLINE int net_io_write_async(struct flb_coro *co,
     return bytes;
 }
 
+static ssize_t fd_io_read(int fd, void *buf, size_t len);
 static ssize_t net_io_read(struct flb_upstream_conn *u_conn,
                            void *buf, size_t len)
+{
+    return fd_io_read(u_conn->fd, buf, len);
+}
+
+static ssize_t fd_io_read(int fd, void *buf, size_t len)
 {
     int ret;
 
-    ret = recv(u_conn->fd, buf, len, 0);
+    ret = recv(fd, buf, len, 0);
     if (ret == -1) {
         ret = FLB_WOULDBLOCK();
         if (ret) {
@@ -368,6 +382,13 @@ static FLB_INLINE ssize_t net_io_read_async(struct flb_coro *co,
     return ret;
 }
 
+/* Write data to fd. For unix socket. */
+int flb_io_fd_write(int fd, const void *data, size_t len, size_t *out_len)
+{
+    /* TODO: support async mode */
+    return fd_io_write(fd, data, len, out_len);
+}
+
 /* Write data to an upstream connection/server */
 int flb_io_net_write(struct flb_upstream_conn *u_conn, const void *data,
                      size_t len, size_t *out_len)
@@ -408,6 +429,12 @@ int flb_io_net_write(struct flb_upstream_conn *u_conn, const void *data,
     return ret;
 }
 
+ssize_t flb_io_fd_read(int fd, void *buf, size_t len)
+{
+    /* TODO: support async mode */
+    return fd_io_read(fd, buf, len);
+}
+
 ssize_t flb_io_net_read(struct flb_upstream_conn *u_conn, void *buf, size_t len)
 {
     int ret = -1;