diff --git a/relayapi/storage/tables/interface.go b/relayapi/storage/tables/interface.go
index a615c7848..9056a5678 100644
--- a/relayapi/storage/tables/interface.go
+++ b/relayapi/storage/tables/interface.go
@@ -21,15 +21,46 @@ import (
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
+// RelayQueue table contains a mapping of server name to transaction id and the corresponding nid.
+// These are the transactions being stored for the given destination server.
+// The nids correspond to entries in the RelayQueueJSON table.
 type RelayQueue interface {
+	// Adds a new transaction_id: server_name mapping with associated json table nid to the table.
+	// Will ensure only one transaction id is present for each server_name: nid mapping.
+	// Adding duplicates will silently do nothing.
 	InsertQueueEntry(ctx context.Context, txn *sql.Tx, transactionID gomatrixserverlib.TransactionID, serverName gomatrixserverlib.ServerName, nid int64) error
+
+	// Removes multiple entries from the table corresponding the the list of nids provided.
+	// If any of the provided nids don't match a row in the table, that deletion is considered
+	// successful.
 	DeleteQueueEntries(ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, jsonNIDs []int64) error
+
+	// Get a list of nids associated with the provided server name.
+	// Returns up to `limit` nids. The entries are returned oldest first.
+	// Will return an empty list if no matches were found.
 	SelectQueueEntries(ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, limit int) ([]int64, error)
+
+	// Get the number of entries in the table associated with the provided server name.
+	// If there are no matching rows, a count of 0 is returned with err set to nil.
 	SelectQueueEntryCount(ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName) (int64, error)
 }
 
+// RelayQueueJSON table contains a map of nid to the raw transaction json.
 type RelayQueueJSON interface {
+	// Adds a new transaction to the table.
+	// Adding a duplicate transaction will result in a new row being added and a new unique nid.
+	// return: unique nid representing this entry.
 	InsertQueueJSON(ctx context.Context, txn *sql.Tx, json string) (int64, error)
+
+	// Removes multiple nids from the table.
+	// If any of the provided nids don't match a row in the table, that deletion is considered
+	// successful.
 	DeleteQueueJSON(ctx context.Context, txn *sql.Tx, nids []int64) error
+
+	// Get the transaction json corresponding to the provided nids.
+	// Will return a partial result containing any matching nid from the table.
+	// Will return an empty map if no matches were found.
+	// It is the caller's responsibility to deal with the results appropriately.
+	// return: map indexed by nid of each matching transaction json.
 	SelectQueueJSON(ctx context.Context, txn *sql.Tx, jsonNIDs []int64) (map[int64][]byte, error)
 }