diff --git a/authentication/pkg.go b/authentication/pkg.go
index bcd84ed..9eb6245 100644
--- a/authentication/pkg.go
+++ b/authentication/pkg.go
@@ -2,8 +2,9 @@ package authentication
 
 import (
 	// External
-	_ "git.gibonuddevalla.se/go/wrappederror"
+	werr "git.gibonuddevalla.se/go/wrappederror"
 	"github.com/golang-jwt/jwt/v5"
+	"github.com/google/uuid"
 	"github.com/jmoiron/sqlx"
 	"github.com/lib/pq"
 
@@ -146,6 +147,14 @@ func (mngr *Manager) AuthenticationHandler(w http.ResponseWriter, r *http.Reques
 	data["uid"] = user.ID
 	data["login"] = user.Username
 	data["name"] = user.Name
+
+	data["cid"], err = mngr.NewClientUUID(user)
+	if err != nil {
+		mngr.log.Error("authentication", "error", err)
+		httpError(w, err)
+		return
+	}
+
 	token, err = mngr.GenerateToken(data)
 	if err != nil {
 		mngr.log.Error("authentication", "error", err)
@@ -269,3 +278,31 @@ func (mngr *Manager) ChangePassword(username, currentPassword, newPassword strin
 	changed = (rowsAffected == 1)
 	return
 } // }}}
+func (mngr *Manager) NewClientUUID(user User) (clientUUID string, err error) { // {{{
+	// Each client session has its own UUID.
+	// Loop through until a unique one is established.
+	var proposedClientUUID string
+	var numSessions int
+	for {
+		proposedClientUUID = uuid.NewString()
+		row := mngr.db.QueryRow("SELECT COUNT(id) FROM public.client WHERE client_uuid = $1", proposedClientUUID)
+		err = row.Scan(&numSessions)
+		if err != nil {
+			err = werr.Wrap(err).WithData(proposedClientUUID)
+			return
+		}
+
+		if numSessions > 0 {
+			continue
+		}
+
+		_, err = mngr.db.Exec(`INSERT INTO public.client(user_id, client_uuid) VALUES($1, $2)`, user.ID, proposedClientUUID)
+		if err != nil {
+			err = werr.Wrap(err).WithData(proposedClientUUID)
+			return
+		}
+		clientUUID = proposedClientUUID
+		break
+	}
+	return
+} // }}}
diff --git a/main.go b/main.go
index 7e63d9e..5bd0f5e 100644
--- a/main.go
+++ b/main.go
@@ -167,7 +167,7 @@ func authenticated(fn func(http.ResponseWriter, *http.Request)) func(http.Respon
 		user := NewUser(claims)
 		r = r.WithContext(context.WithValue(r.Context(), CONTEXT_USER, user))
 
-		Log.Info("webserver", "op", "request", "method", r.Method, "url", r.URL.String(), "username", user.Username)
+		Log.Debug("webserver", "op", "request", "method", r.Method, "url", r.URL.String(), "username", user.Username, "client", user.ClientUUID)
 		fn(w, r)
 	}
 } // }}}
@@ -246,22 +246,11 @@ func actionSyncFromServer(w http.ResponseWriter, r *http.Request) { // {{{
 	// The purpose of the Client UUID is to avoid
 	// sending nodes back once again to a client that
 	// just created or modified it.
-	request := struct {
-		ClientUUID string
-	}{}
-	body, _ := io.ReadAll(r.Body)
-	err := json.Unmarshal(body, &request)
-	if err != nil {
-		Log.Error("/node/tree", "error", err)
-		httpError(w, err)
-		return
-	}
-
 	user := getUser(r)
 	changedFrom, _ := strconv.Atoi(r.PathValue("sequence"))
 	offset, _ := strconv.Atoi(r.PathValue("offset"))
 
-	nodes, maxSeq, moreRowsExist, err := Nodes(user.ID, offset, uint64(changedFrom), request.ClientUUID)
+	nodes, maxSeq, moreRowsExist, err := Nodes(user.UserID, offset, uint64(changedFrom), user.ClientUUID)
 	if err != nil {
 		Log.Error("/node/tree", "error", err)
 		httpError(w, err)
@@ -285,7 +274,7 @@ func actionNodeRetrieve(w http.ResponseWriter, r *http.Request) { // {{{
 	var err error
 
 	uuid := r.PathValue("uuid")
-	node, err := RetrieveNode(user.ID, uuid)
+	node, err := RetrieveNode(user.UserID, uuid)
 	if err != nil {
 		responseError(w, err)
 		return
@@ -301,7 +290,6 @@ func actionSyncToServer(w http.ResponseWriter, r *http.Request) { // {{{
 
 	body, _ := io.ReadAll(r.Body)
 	var request struct {
-		ClientUUID string
 		NodeData   string
 	}
 	err := json.Unmarshal(body, &request)
@@ -310,7 +298,7 @@ func actionSyncToServer(w http.ResponseWriter, r *http.Request) { // {{{
 		return
 	}
 
-	db.Exec(`CALL add_nodes($1, $2, $3::jsonb)`, user.ID, request.ClientUUID, request.NodeData)
+	db.Exec(`CALL add_nodes($1, $2, $3::jsonb)`, user.UserID, user.ClientUUID, request.NodeData)
 
 	responseData(w, map[string]interface{}{
 		"OK": true,
@@ -359,7 +347,7 @@ func changePassword(username string) { // {{{
 
 	fmt.Printf("\nPassword changed\n")
 } // }}}
-func getUser(r *http.Request) User { // {{{
-	user, _ := r.Context().Value(CONTEXT_USER).(User)
+func getUser(r *http.Request) UserSession { // {{{
+	user, _ := r.Context().Value(CONTEXT_USER).(UserSession)
 	return user
 } // }}}
diff --git a/sql/00010.sql b/sql/00010.sql
new file mode 100644
index 0000000..c0f14ee
--- /dev/null
+++ b/sql/00010.sql
@@ -0,0 +1,10 @@
+CREATE TABLE public.client (
+	id serial NOT NULL,
+	user_id int4 NOT NULL,
+	client_uuid bpchar(36) DEFAULT '' NOT NULL,
+	created timestamptz DEFAULT NOW() NOT NULL,
+	description varchar DEFAULT '' NOT NULL,
+	CONSTRAINT client_pk PRIMARY KEY (id)
+);
+
+CREATE UNIQUE INDEX client_uuid_idx ON public.client (client_uuid);
diff --git a/static/js/node_store.mjs b/static/js/node_store.mjs
index c640cc6..e1253a4 100644
--- a/static/js/node_store.mjs
+++ b/static/js/node_store.mjs
@@ -70,7 +70,6 @@ export class NodeStore {
 				this.sendQueue = new SimpleNodeStore(this.db, 'send_queue')
 				this.nodesHistory = new SimpleNodeStore(this.db, 'nodes_history')
 				this.initializeRootNode()
-					.then(() => this.initializeClientUUID())
 					.then(() => resolve())
 			}
 
@@ -110,13 +109,6 @@ export class NodeStore {
 			getRequest.onerror = (event) => reject(event.target.error)
 		})
 	}//}}}
-	async initializeClientUUID() {//{{{
-		let clientUUID = await this.getAppState('client_uuid')
-		if (clientUUID !== null)
-			return
-		clientUUID = crypto.randomUUID()
-		return this.setAppState('client_uuid', clientUUID)
-	}//}}}
 
 	node(uuid, dataIfUndefined, newLevel) {//{{{
 		let n = this.nodes[uuid]
diff --git a/static/js/sync.mjs b/static/js/sync.mjs
index 95d554d..6321db6 100644
--- a/static/js/sync.mjs
+++ b/static/js/sync.mjs
@@ -13,7 +13,6 @@ export class Sync {
 			// The latest sync node value is used to retrieve the changes
 			// from the backend.
 			const state = await nodeStore.getAppState('latest_sync_node')
-			const clientUUID = await nodeStore.getAppState('client_uuid')
 			const oldMax = (state?.value ? state.value : 0)
 			let currMax = oldMax
 
@@ -22,7 +21,7 @@ export class Sync {
 			let batch = 0
 			do {
 				batch++
-				res = await API.query('POST', `/sync/from_server/${oldMax}/${offset}`, { ClientUUID: clientUUID.value })
+				res = await API.query('POST', `/sync/from_server/${oldMax}/${offset}`)
 				if (res.Nodes.length > 0)
 					console.log(`Node sync batch #${batch}`)
 				offset += res.Nodes.length
@@ -96,10 +95,8 @@ export class Sync {
 					break
 				console.debug(`Sending ${nodesToSend.length} node(s) to server`)
 
-				const clientUUID = await nodeStore.getAppState('client_uuid')
 				const request = {
 					NodeData: JSON.stringify(nodesToSend),
-					ClientUUID: clientUUID.value,
 				}
 				const res = await API.query('POST', '/sync/to_server', request)
 				if (!res.OK) {
diff --git a/user.go b/user.go
index fcd1cb9..b1c2abf 100644
--- a/user.go
+++ b/user.go
@@ -5,20 +5,23 @@ import (
 	"github.com/golang-jwt/jwt/v5"
 )
 
-type User struct {
-	ID       int
-	Username string
-	Password string
-	Name     string
+type UserSession struct {
+	UserID         int
+	Username   string
+	Password   string
+	Name       string
+	ClientUUID string
 }
 
-func NewUser(claims jwt.MapClaims) (u User) {
+func NewUser(claims jwt.MapClaims) (u UserSession) {
 	uid, _ := claims["uid"].(float64)
 	name, _ := claims["name"].(string)
 	username, _ := claims["login"].(string)
+	clientUUID, _ := claims["cid"].(string)
 
-	u.ID = int(uid)
+	u.UserID = int(uid)
 	u.Username = username
 	u.Name = name
+	u.ClientUUID = clientUUID
 	return
 }