diff --git a/core/kg/model/config.go b/core/kg/model/config.go
new file mode 100644
index 0000000..991ea5d
--- /dev/null
+++ b/core/kg/model/config.go
@@ -0,0 +1,29 @@
+package model
+
+const (
+	databaseDriverPostgres = "postgres"
+	defaultDataSource      = "postgres://user:test@localhost/pcloud_test?sslmode=disable&connect_timeout=10"
+)
+
+type Config struct {
+	SqlSettings SqlSettings
+}
+
+func (c *Config) SetDefaults() {
+	c.SqlSettings.SetDefaults()
+}
+
+type SqlSettings struct {
+	DriverName string `access:"environment,write_restrictable,cloud_restrictable"`
+	DataSource string `access:"environment,write_restrictable,cloud_restrictable"`
+}
+
+func (s *SqlSettings) SetDefaults() {
+	if s.DriverName == "" {
+		s.DriverName = databaseDriverPostgres
+	}
+
+	if s.DataSource == "" {
+		s.DataSource = defaultDataSource
+	}
+}
diff --git a/core/kg/model/user.go b/core/kg/model/user.go
new file mode 100644
index 0000000..4ed6cc8
--- /dev/null
+++ b/core/kg/model/user.go
@@ -0,0 +1,112 @@
+package model
+
+import (
+	"net/mail"
+	"regexp"
+	"strings"
+	"unicode"
+
+	"github.com/pkg/errors"
+)
+
+const (
+	userNameMaxLength  = 64
+	userNameMinLength  = 1
+	userEmailMaxLength = 128
+)
+
+// User contains the details about the user.
+// This struct's serializer methods are auto-generated. If a new field is added/removed,
+// please run make gen-serialized.
+type User struct {
+	ID                 string `json:"id"`
+	CreateAt           int64  `json:"create_at,omitempty"`
+	UpdateAt           int64  `json:"update_at,omitempty"`
+	DeleteAt           int64  `json:"delete_at"`
+	Username           string `json:"username"`
+	Password           string `json:"password,omitempty"`
+	Email              string `json:"email"`
+	EmailVerified      bool   `json:"email_verified,omitempty"`
+	FirstName          string `json:"first_name"`
+	LastName           string `json:"last_name"`
+	LastPasswordUpdate int64  `json:"last_password_update,omitempty"`
+}
+
+// IsValid validates the user and returns an error if it isn't configured
+// correctly.
+func (u *User) IsValid() error {
+	if !isValidID(u.ID) {
+		return invalidUserError("id", "")
+	}
+
+	if u.CreateAt == 0 {
+		return invalidUserError("create_at", u.ID)
+	}
+
+	if u.UpdateAt == 0 {
+		return invalidUserError("update_at", u.ID)
+	}
+
+	if !isValidUsername(u.Username) {
+		return invalidUserError("username", u.ID)
+	}
+
+	if !isValidEmail(u.Email) {
+		return invalidUserError("email", u.ID)
+	}
+
+	return nil
+}
+
+func isValidID(value string) bool {
+	if len(value) != 26 {
+		return false
+	}
+
+	for _, r := range value {
+		if !unicode.IsLetter(r) && !unicode.IsNumber(r) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func invalidUserError(fieldName string, userID string) error {
+	return errors.Errorf("Invalid User field: %s; id: %s", fieldName, userID)
+}
+
+func isValidUsername(s string) bool {
+	if len(s) < userNameMinLength || len(s) > userNameMaxLength {
+		return false
+	}
+
+	validUsernameChars := regexp.MustCompile(`^[a-z0-9\.\-_]+$`)
+	if !validUsernameChars.MatchString(s) {
+		return false
+	}
+
+	return true
+}
+
+func isValidEmail(email string) bool {
+	if len(email) > userEmailMaxLength || email == "" {
+		return false
+	}
+	if !isLower(email) {
+		return false
+	}
+
+	if addr, err := mail.ParseAddress(email); err != nil {
+		return false
+	} else if addr.Name != "" {
+		// mail.ParseAddress accepts input of the form "Billy Bob <billy@example.com>" which we don't allow
+		return false
+	}
+
+	return true
+}
+
+func isLower(s string) bool {
+	return strings.ToLower(s) == s
+}