diff --git a/internal/router/session.go b/internal/router/session.go
index a42f04bfb..3276c38aa 100644
--- a/internal/router/session.go
+++ b/internal/router/session.go
@@ -23,6 +23,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"net/url"
 
 	"github.com/gin-contrib/sessions"
 	"github.com/gin-contrib/sessions/memstore"
@@ -31,8 +32,8 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 )
 
-// SessionOptions returns the standard set of options to use for each session.
-func SessionOptions(cfg *config.Config) sessions.Options {
+// sessionOptions returns the standard set of options to use for each session.
+func sessionOptions(cfg *config.Config) sessions.Options {
 	return sessions.Options{
 		Path:     "/",
 		Domain:   cfg.Host,
@@ -43,6 +44,22 @@ func SessionOptions(cfg *config.Config) sessions.Options {
 	}
 }
 
+func sessionName(cfg *config.Config) (string, error) {
+	// parse the protocol + host
+	u, err := url.Parse(fmt.Sprintf("%s://%s", cfg.Protocol, cfg.Host))
+	if err != nil {
+		return "", err
+	}
+
+	// take the hostname without any port attached
+	strippedHostname := u.Hostname()
+	if strippedHostname == "" {
+		return "", fmt.Errorf("could not derive hostname without port from %s://%s", cfg.Protocol, cfg.Host)
+	}
+
+	return fmt.Sprintf("gotosocial-%s", strippedHostname), nil
+}
+
 func useSession(ctx context.Context, cfg *config.Config, sessionDB db.Session, engine *gin.Engine) error {
 	// check if we have a saved router session already
 	rs, err := sessionDB.GetSession(ctx)
@@ -54,8 +71,13 @@ func useSession(ctx context.Context, cfg *config.Config, sessionDB db.Session, e
 	}
 
 	store := memstore.NewStore(rs.Auth, rs.Crypt)
-	store.Options(SessionOptions(cfg))
-	sessionName := fmt.Sprintf("gotosocial-%s", cfg.Host)
+	store.Options(sessionOptions(cfg))
+
+	sessionName, err := sessionName(cfg)
+	if err != nil {
+		return err
+	}
+
 	engine.Use(sessions.Sessions(sessionName, store))
 	return nil
 }
diff --git a/internal/router/session_test.go b/internal/router/session_test.go
new file mode 100644
index 000000000..7c2d324fd
--- /dev/null
+++ b/internal/router/session_test.go
@@ -0,0 +1,87 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package router
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+)
+
+type SessionTestSuite struct {
+	suite.Suite
+}
+
+func (suite *SessionTestSuite) TestDeriveSessionNameLocalhostWithPort() {
+	cfg := &config.Config{
+		Protocol: "http",
+		Host:     "localhost:8080",
+	}
+
+	sessionName, err := sessionName(cfg)
+	suite.NoError(err)
+	suite.Equal("gotosocial-localhost", sessionName)
+}
+
+func (suite *SessionTestSuite) TestDeriveSessionNameLocalhost() {
+	cfg := &config.Config{
+		Protocol: "http",
+		Host:     "localhost",
+	}
+
+	sessionName, err := sessionName(cfg)
+	suite.NoError(err)
+	suite.Equal("gotosocial-localhost", sessionName)
+}
+
+func (suite *SessionTestSuite) TestDeriveSessionNoProtocol() {
+	cfg := &config.Config{
+		Host: "localhost",
+	}
+
+	sessionName, err := sessionName(cfg)
+	suite.EqualError(err, "parse \"://localhost\": missing protocol scheme")
+	suite.Equal("", sessionName)
+}
+
+func (suite *SessionTestSuite) TestDeriveSessionNoHost() {
+	cfg := &config.Config{
+		Protocol: "https",
+	}
+
+	sessionName, err := sessionName(cfg)
+	suite.EqualError(err, "could not derive hostname without port from https://")
+	suite.Equal("", sessionName)
+}
+
+func (suite *SessionTestSuite) TestDeriveSessionOK() {
+	cfg := &config.Config{
+		Protocol: "https",
+		Host:     "example.org",
+	}
+
+	sessionName, err := sessionName(cfg)
+	suite.NoError(err)
+	suite.Equal("gotosocial-example.org", sessionName)
+}
+
+func TestSessionTestSuite(t *testing.T) {
+	suite.Run(t, &SessionTestSuite{})
+}
diff --git a/internal/router/template.go b/internal/router/template.go
index 787ade799..e7bdc3edf 100644
--- a/internal/router/template.go
+++ b/internal/router/template.go
@@ -1,3 +1,21 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
 package router
 
 import (