diff --git a/go.mod b/go.mod
index e2ffb7c..995478b 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,7 @@ module github.com/bouncepaw/mycorrhiza
 
 go 1.14
 
-require github.com/valyala/quicktemplate v1.6.3
+require (
+	github.com/adrg/xdg v0.2.2
+	github.com/valyala/quicktemplate v1.6.3
+)
diff --git a/go.sum b/go.sum
index a9a43a1..dbbc51b 100644
--- a/go.sum
+++ b/go.sum
@@ -1,6 +1,12 @@
+github.com/adrg/xdg v0.2.2 h1:A7ZHKRz5KGOLJX/bg7IPzStryhvCzAE1wX+KWawPiAo=
+github.com/adrg/xdg v0.2.2/go.mod h1:7I2hH/IT30IsupOpKZ5ue7/qNi3CoKzD6tL3HwpaRMQ=
 github.com/andybalholm/brotli v1.0.0/go.mod h1:loMXtMfwqflxFJPmdbJO0a3KNoPuLBgiu3qAvBg8x/Y=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/klauspost/compress v1.10.7/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/klauspost/compress v1.11.0/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
 github.com/valyala/fasthttp v1.16.0/go.mod h1:YOKImeEosDdBPnxc0gy7INqi3m1zK6A+xl6TwOBhHCA=
@@ -13,3 +19,5 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200602225109-6fdc65e7d980/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/user/fs.go b/user/fs.go
new file mode 100644
index 0000000..f47c423
--- /dev/null
+++ b/user/fs.go
@@ -0,0 +1,69 @@
+package user
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"github.com/adrg/xdg"
+	"github.com/bouncepaw/mycorrhiza/util"
+)
+
+func PopulateFixedUserStorage() {
+	contents, err := ioutil.ReadFile(util.FixedCredentialsPath)
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = json.Unmarshal(contents, &UserStorage.Users)
+	if err != nil {
+		log.Fatal(err)
+	}
+	for _, user := range UserStorage.Users {
+		user.Group = groupFromString(user.GroupString)
+	}
+	log.Println("Found", len(UserStorage.Users), "fixed users")
+
+	contents, err = ioutil.ReadFile(tokenStoragePath())
+	if os.IsNotExist(err) {
+		return
+	}
+	if err != nil {
+		log.Fatal(err)
+	}
+	var tmp map[string]string
+	err = json.Unmarshal(contents, &tmp)
+	if err != nil {
+		log.Fatal(err)
+	}
+	for token, username := range tmp {
+		user := UserStorage.userByName(username)
+		UserStorage.Tokens[token] = user
+	}
+	log.Println("Found", len(tmp), "active sessions")
+}
+
+func dumpTokens() {
+	tmp := make(map[string]string)
+	for token, user := range UserStorage.Tokens {
+		tmp[token] = user.Name
+	}
+	blob, err := json.Marshal(tmp)
+	if err != nil {
+		log.Println(err)
+	} else {
+		ioutil.WriteFile(tokenStoragePath(), blob, 0644)
+	}
+}
+
+// Return path to tokens.json.
+func tokenStoragePath() string {
+	dir, err := xdg.DataFile("mycorrhiza/tokens.json")
+	if err != nil {
+		// Yes, it is unix-only, but function above rarely fails, so this block is probably never reached.
+		path := "/home/" + os.Getenv("HOME") + "/.local/share/mycorrhiza/tokens.json"
+		os.MkdirAll(path, 0777)
+		return path
+	}
+	return dir
+}
diff --git a/user/group.go b/user/group.go
new file mode 100644
index 0000000..8ff7f1f
--- /dev/null
+++ b/user/group.go
@@ -0,0 +1,61 @@
+package user
+
+import (
+	"log"
+)
+
+func groupFromString(s string) UserGroup {
+	switch s {
+	case "admin":
+		return UserAdmin
+	case "moderator":
+		return UserModerator
+	case "trusted":
+		return UserTrusted
+	case "editor":
+		return UserEditor
+	default:
+		log.Fatal("Unknown user group", s)
+		return UserAnon
+	}
+}
+
+// UserGroup represents a group that a user is part of.
+type UserGroup int
+
+const (
+	// UserAnon is the default user group which all unauthorized visitors have.
+	UserAnon UserGroup = iota
+	// UserEditor is a user who can edit and upload stuff.
+	UserEditor
+	// UserTrusted is a trusted editor who can also rename stuff.
+	UserTrusted
+	// UserModerator is a moderator who can also delete stuff.
+	UserModerator
+	// UserAdmin can do everything.
+	UserAdmin
+)
+
+var minimalRights = map[string]UserGroup{
+	"edit":           UserEditor,
+	"upload-binary":  UserEditor,
+	"upload-text":    UserEditor,
+	"rename-ask":     UserTrusted,
+	"rename-confirm": UserTrusted,
+	"delete-ask":     UserModerator,
+	"delete-confirm": UserModerator,
+	"reindex":        UserAdmin,
+}
+
+func (ug UserGroup) CanAccessRoute(route string) bool {
+	if !AuthUsed {
+		return true
+	}
+	if minimalRight, ok := minimalRights[route]; ok {
+		if ug >= minimalRight {
+			return true
+		}
+		return false
+	}
+	return true
+}
diff --git a/user/user.go b/user/user.go
index b69268d..ed7ec42 100644
--- a/user/user.go
+++ b/user/user.go
@@ -1,8 +1,6 @@
 package user
 
 import (
-	"encoding/json"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"time"
@@ -25,6 +23,15 @@ func (us *FixedUserStorage) userByToken(token string) *User {
 	return nil
 }
 
+func (us *FixedUserStorage) userByName(username string) *User {
+	for _, user := range us.Users {
+		if user.Name == username {
+			return user
+		}
+	}
+	return nil
+}
+
 func FromRequest(rq *http.Request) *User {
 	cookie, err := rq.Cookie("mycorrhiza_token")
 	if err != nil {
@@ -62,6 +69,7 @@ func AddSession(username string) (string, error) {
 		for _, user := range UserStorage.Users {
 			if user.Name == username {
 				UserStorage.Tokens[token] = user
+				go dumpTokens()
 			}
 		}
 		log.Println("New token for", username, "is", token)
@@ -71,6 +79,7 @@ func AddSession(username string) (string, error) {
 
 func terminateSession(token string) {
 	delete(UserStorage.Tokens, token)
+	go dumpTokens()
 }
 
 func HasUsername(username string) bool {
@@ -98,21 +107,6 @@ type FixedUserStorage struct {
 
 var UserStorage = FixedUserStorage{Tokens: make(map[string]*User)}
 
-func PopulateFixedUserStorage() {
-	contents, err := ioutil.ReadFile(util.FixedCredentialsPath)
-	if err != nil {
-		log.Fatal(err)
-	}
-	err = json.Unmarshal(contents, &UserStorage.Users)
-	if err != nil {
-		log.Fatal(err)
-	}
-	for _, user := range UserStorage.Users {
-		user.Group = groupFromString(user.GroupString)
-	}
-	log.Println("Found", len(UserStorage.Users), "fixed users")
-}
-
 // AuthUsed shows if a method of authentication is used. You should set it by yourself.
 var AuthUsed bool
 
@@ -126,62 +120,6 @@ type User struct {
 	Password    string    `json:"password"`
 }
 
-func groupFromString(s string) UserGroup {
-	switch s {
-	case "admin":
-		return UserAdmin
-	case "moderator":
-		return UserModerator
-	case "trusted":
-		return UserTrusted
-	case "editor":
-		return UserEditor
-	default:
-		log.Fatal("Unknown user group", s)
-		return UserAnon
-	}
-}
-
-// UserGroup represents a group that a user is part of.
-type UserGroup int
-
-const (
-	// UserAnon is the default user group which all unauthorized visitors have.
-	UserAnon UserGroup = iota
-	// UserEditor is a user who can edit and upload stuff.
-	UserEditor
-	// UserTrusted is a trusted editor who can also rename stuff.
-	UserTrusted
-	// UserModerator is a moderator who can also delete stuff.
-	UserModerator
-	// UserAdmin can do everything.
-	UserAdmin
-)
-
-var minimalRights = map[string]UserGroup{
-	"edit":           UserEditor,
-	"upload-binary":  UserEditor,
-	"upload-text":    UserEditor,
-	"rename-ask":     UserTrusted,
-	"rename-confirm": UserTrusted,
-	"delete-ask":     UserModerator,
-	"delete-confirm": UserModerator,
-	"reindex":        UserAdmin,
-}
-
-func (ug UserGroup) CanAccessRoute(route string) bool {
-	if !AuthUsed {
-		return true
-	}
-	if minimalRight, ok := minimalRights[route]; ok {
-		if ug >= minimalRight {
-			return true
-		}
-		return false
-	}
-	return true
-}
-
 // A handy cookie constructor
 func cookie(name_suffix, val string, t time.Time) *http.Cookie {
 	return &http.Cookie{