diff --git a/storagenode/bandwidth/doc.go b/storagenode/bandwidth/doc.go
new file mode 100644
index 000000000..392997fb4
--- /dev/null
+++ b/storagenode/bandwidth/doc.go
@@ -0,0 +1,5 @@
+// Copyright (C) 2021 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+// Package bandwidth system keeps track of bandwidth usage as reported by order limits and orders.
+package bandwidth
diff --git a/storagenode/inspector/inspector.go b/storagenode/inspector/inspector.go
index 426e43880..ec3f65d24 100644
--- a/storagenode/inspector/inspector.go
+++ b/storagenode/inspector/inspector.go
@@ -1,6 +1,7 @@
 // Copyright (C) 2019 Storj Labs, Inc.
 // See LICENSE for copying information.
 
+// Package inspector provides a private endpoint for monitoring status.
 package inspector
 
 import (
diff --git a/storagenode/monitor/monitor.go b/storagenode/monitor/monitor.go
index aecf1ee44..d6c127e89 100644
--- a/storagenode/monitor/monitor.go
+++ b/storagenode/monitor/monitor.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019 Storj Labs, Inc.
 // See LICENSE for copying information.
 
+// Package monitor is responsible for monitoring the disk is well-behaved.
+// It checks whether there's sufficient space and whether directories are writable.
 package monitor
 
 import (
diff --git a/storagenode/orders/doc.go b/storagenode/orders/doc.go
new file mode 100644
index 000000000..9e149bff0
--- /dev/null
+++ b/storagenode/orders/doc.go
@@ -0,0 +1,7 @@
+// Copyright (C) 2021 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+// Package orders handles order limit management.
+// It contains file database for the orders.
+// Similarly, it manages settlement, where order limits are sent to the satellite.
+package orders
diff --git a/storagenode/pieces/doc.go b/storagenode/pieces/doc.go
new file mode 100644
index 000000000..eebbe38a7
--- /dev/null
+++ b/storagenode/pieces/doc.go
@@ -0,0 +1,6 @@
+// Copyright (C) 2021 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+// Package pieces is responsible for the low level piece management.
+// It also provides ways to keep track of pieces metadata.
+package pieces
diff --git a/storagenode/piecestore/doc.go b/storagenode/piecestore/doc.go
new file mode 100644
index 000000000..12d4a01e3
--- /dev/null
+++ b/storagenode/piecestore/doc.go
@@ -0,0 +1,7 @@
+// Copyright (C) 2021 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+// Package piecestore contains the endpoint for responding to requests from the uplinks and satellites.
+// It implements the upload and download protocol, where the counterpart is in uplink.
+// It uses trust packages to establish trusted satellites.
+package piecestore
diff --git a/storagenode/trust/doc.go b/storagenode/trust/doc.go
new file mode 100644
index 000000000..fd931017c
--- /dev/null
+++ b/storagenode/trust/doc.go
@@ -0,0 +1,5 @@
+// Copyright (C) 2021 Storj Labs, Inc.
+// See LICENSE for copying information.
+
+// Package trust handles rules for accepting and denying connections from satellites.
+package trust