diff --git a/cmd/registeruser/main.go b/cmd/registeruser/main.go
index fd573db..b642ff6 100644
--- a/cmd/registeruser/main.go
+++ b/cmd/registeruser/main.go
@@ -2,6 +2,8 @@ package main
 
 import (
 	"database/sql"
+	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 
@@ -10,22 +12,64 @@ import (
 	"git.tilde.town/tildetown/town/towndb"
 )
 
-// TODO this command adds a new user to /town/var/town.db
-// it's meant to be invoked by the welcome binary upon successfully
-// creating a new user account
+// this command adds a new user to /town/var/town.db. it's meant to be invoked
+// by the welcome binary upon successfully creating a new user account
 
-func _main(db *sql.DB) error {
-	return nil
+func _main(tdb *sql.DB, userData towndb.TownUser) error {
+	if userData.Username == "" {
+		return errors.New("no username")
+	}
+
+	if len(userData.Emails) == 0 {
+		return errors.New("no email set")
+	}
+
+	for _, e := range userData.Emails {
+		if e == "" {
+			return errors.New("blank email in email list")
+		}
+	}
+
+	if userData.IsAdmin {
+		return errors.New("please stop")
+	}
+
+	if userData.State != towndb.StateActive {
+		return errors.New("bad state")
+	}
+
+	return userData.Insert(tdb)
+}
+
+func parseInput(stdin *os.File) (u towndb.TownUser, err error) {
+	var n int
+	input := make([]byte, 3000) // arbitrary
+	if n, err = stdin.Read(input); err != nil {
+		return
+	}
+	if n == 0 {
+		err = errors.New("nothing passed on input")
+		return
+	}
+	err = json.Unmarshal(input[0:n], &u)
+	return
 }
 
 func main() {
-	towndb, err := towndb.ConnectDB()
+	tdb, err := towndb.ConnectDB()
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
 	}
-	if err = _main(towndb); err != nil {
+
+	userData, err := parseInput(os.Stdin)
+	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(2)
 	}
+
+	if err = _main(tdb, userData); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(3)
+	}
 }