diff --git a/netmap/doc.go b/netmap/doc.go
index 082089aa..88505854 100644
--- a/netmap/doc.go
+++ b/netmap/doc.go
@@ -1,5 +1,5 @@
 /*
-Netmap contract is a contract deployed in NeoFS sidechain.
+Package netmap contains implementation of the Netmap contract for NeoFS systems.
 
 Netmap contract stores and manages NeoFS network map, Storage node candidates
 and epoch number counter. In notary disabled environment, contract also stores
@@ -32,3 +32,55 @@ in the network by invoking NewEpoch method.
 	    type: Integer
 */
 package netmap
+
+/*
+Contract storage model.
+
+# Summary
+Key-value storage format:
+ - 'snapshotEpoch' -> int
+   current epoch
+ - 'snapshotBlock' -> int
+   block which "ticked" the current epoch
+ - 'snapshotCount' -> int
+   number of stored network maps including current one
+ - 'snapshot_<ID>' -> std.Serialize([]Node)
+   network map by snapshot ID (where Node is a type)
+ - 'snapshotCurrent' -> int
+   ID of the snapshot representing current network map
+ - 'candidate<public_key>' -> std.Serialize(Node)
+   information about the particular network map candidate (where Node is a type)
+ - 'containerScriptHash' -> 20-byte script hash
+   Container contract reference
+ - 'balanceScriptHash' -> 20-byte script hash
+   Balance contract reference
+ - 'notary' -> bool
+   is notary mode disabled
+ - 'innerring' -> []interop.PublicKey
+   public keys of the Inner Ring members
+ - 'config<name>' -> []byte
+   value of the particular NeoFS network parameter
+
+# Setting
+Contract can be deployed in notary and notary-disabled mode. In notary-disabled
+mode contract stores the Inner Ring members.
+
+To handle some events, the contract refers to other contracts.
+
+# Epoch
+Contract stores the current (last) NeoFS timestamp for the network within which
+the contract is deployed.
+
+# Network maps
+Contract records set of network parties representing the network map. Current
+network map is updated on each epoch tick. Contract also holds limited number of
+previous network maps (SNAPSHOT_LIMIT). Timestamped network maps are called
+snapshots. Snapshots are identified by the numerical ring [0:SNAPSHOT_LIMIT).
+
+# Network map candidates
+Contract stores information about the network parties which were requested to be
+added to the network map.
+
+# Network configuration
+Contract stores NeoFS network configuration declared in the NeoFS API protocol.
+*/