diff --git a/userapi/storage/postgres/account_data_table.go b/userapi/storage/postgres/account_data_table.go
index 71cead0d0..07dba66b1 100644
--- a/userapi/storage/postgres/account_data_table.go
+++ b/userapi/storage/postgres/account_data_table.go
@@ -38,13 +38,13 @@ CREATE TABLE IF NOT EXISTS userapi_account_datas (
     -- The account data content
     content TEXT NOT NULL,
 
-    PRIMARY KEY(localpart, room_id, type)
+    PRIMARY KEY(localpart, server_name, room_id, type)
 );
 `
 
 const insertAccountDataSQL = `
 	INSERT INTO userapi_account_datas(localpart, server_name, room_id, type, content) VALUES($1, $2, $3, $4, $5)
-	ON CONFLICT (localpart, room_id, type) DO UPDATE SET content = EXCLUDED.content
+	ON CONFLICT (localpart, server_name, room_id, type) DO UPDATE SET content = EXCLUDED.content
 `
 
 const selectAccountDataSQL = "" +
diff --git a/userapi/storage/postgres/accounts_table.go b/userapi/storage/postgres/accounts_table.go
index 9b30b5d8f..1512eb818 100644
--- a/userapi/storage/postgres/accounts_table.go
+++ b/userapi/storage/postgres/accounts_table.go
@@ -35,7 +35,7 @@ const accountsSchema = `
 -- Stores data about accounts.
 CREATE TABLE IF NOT EXISTS userapi_accounts (
     -- The Matrix user ID localpart for this account
-    localpart TEXT NOT NULL PRIMARY KEY,
+    localpart TEXT NOT NULL,
 	server_name TEXT NOT NULL,
     -- When this account was first created, as a unix timestamp (ms resolution).
     created_ts BIGINT NOT NULL,
@@ -46,9 +46,10 @@ CREATE TABLE IF NOT EXISTS userapi_accounts (
     -- If the account is currently active
     is_deactivated BOOLEAN DEFAULT FALSE,
 	-- The account_type (user = 1, guest = 2, admin = 3, appservice = 4)
-	account_type SMALLINT NOT NULL
+	account_type SMALLINT NOT NULL,
     -- TODO:
     -- upgraded_ts, devices, any email reset stuff?
+	PRIMARY KEY (localpart, server_name)
 );
 `
 
@@ -138,8 +139,8 @@ func (s *accountsStatements) InsertAccount(
 
 	return &api.Account{
 		Localpart:    localpart,
-		UserID:       userutil.MakeUserID(localpart, s.serverName),
-		ServerName:   s.serverName,
+		UserID:       userutil.MakeUserID(localpart, serverName),
+		ServerName:   serverName,
 		AppServiceID: appserviceID,
 		AccountType:  accountType,
 	}, nil
@@ -185,9 +186,7 @@ func (s *accountsStatements) SelectAccountByLocalpart(
 		acc.AppServiceID = appserviceIDPtr.String
 	}
 
-	acc.UserID = userutil.MakeUserID(localpart, s.serverName)
-	acc.ServerName = s.serverName
-
+	acc.UserID = userutil.MakeUserID(acc.Localpart, acc.ServerName)
 	return &acc, nil
 }
 
diff --git a/userapi/storage/postgres/devices_table.go b/userapi/storage/postgres/devices_table.go
index cd715437b..2dd216189 100644
--- a/userapi/storage/postgres/devices_table.go
+++ b/userapi/storage/postgres/devices_table.go
@@ -67,7 +67,7 @@ CREATE TABLE IF NOT EXISTS userapi_devices (
 );
 
 -- Device IDs must be unique for a given user.
-CREATE UNIQUE INDEX IF NOT EXISTS userapi_device_localpart_id_idx ON userapi_devices(localpart, device_id);
+CREATE UNIQUE INDEX IF NOT EXISTS userapi_device_localpart_id_idx ON userapi_devices(localpart, server_name, device_id);
 `
 
 const insertDeviceSQL = "" +
diff --git a/userapi/storage/postgres/openid_table.go b/userapi/storage/postgres/openid_table.go
index 953956aa5..68d87f007 100644
--- a/userapi/storage/postgres/openid_table.go
+++ b/userapi/storage/postgres/openid_table.go
@@ -60,7 +60,7 @@ func (s *openIDTokenStatements) InsertOpenIDToken(
 	expiresAtMS int64,
 ) (err error) {
 	stmt := sqlutil.TxStmt(txn, s.insertTokenStmt)
-	_, err = stmt.ExecContext(ctx, token, serverName, localpart, expiresAtMS)
+	_, err = stmt.ExecContext(ctx, token, localpart, serverName, expiresAtMS)
 	return
 }
 
diff --git a/userapi/storage/postgres/profile_table.go b/userapi/storage/postgres/profile_table.go
index 28d24a4d0..0d0ff705c 100644
--- a/userapi/storage/postgres/profile_table.go
+++ b/userapi/storage/postgres/profile_table.go
@@ -30,12 +30,13 @@ const profilesSchema = `
 -- Stores data about accounts profiles.
 CREATE TABLE IF NOT EXISTS userapi_profiles (
     -- The Matrix user ID localpart for this account
-    localpart TEXT NOT NULL PRIMARY KEY,
+    localpart TEXT NOT NULL,
 	server_name TEXT NOT NULL,
     -- The display name for this account
     display_name TEXT,
     -- The URL of the avatar for this account
-    avatar_url TEXT
+    avatar_url TEXT,
+	PRIMARY KEY (localpart, server_name)
 );
 `
 
diff --git a/userapi/storage/postgres/threepid_table.go b/userapi/storage/postgres/threepid_table.go
index 8578e018e..f41c43122 100644
--- a/userapi/storage/postgres/threepid_table.go
+++ b/userapi/storage/postgres/threepid_table.go
@@ -39,7 +39,7 @@ CREATE TABLE IF NOT EXISTS userapi_threepids (
 	PRIMARY KEY(threepid, medium)
 );
 
-CREATE INDEX IF NOT EXISTS userapi_threepid_idx ON userapi_threepids(localpart);
+CREATE INDEX IF NOT EXISTS userapi_threepid_idx ON userapi_threepids(localpart, server_name);
 `
 
 const selectLocalpartForThreePIDSQL = "" +
diff --git a/userapi/storage/shared/storage.go b/userapi/storage/shared/storage.go
index c02ad6d12..4eac1ad56 100644
--- a/userapi/storage/shared/storage.go
+++ b/userapi/storage/shared/storage.go
@@ -293,7 +293,7 @@ func (d *Database) SaveThreePIDAssociation(
 	medium string,
 ) (err error) {
 	return d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
-		user, domain, err := d.ThreePIDs.SelectLocalpartForThreePID(
+		user, _, err := d.ThreePIDs.SelectLocalpartForThreePID(
 			ctx, txn, threepid, medium,
 		)
 		if err != nil {
@@ -304,7 +304,7 @@ func (d *Database) SaveThreePIDAssociation(
 			return Err3PIDInUse
 		}
 
-		return d.ThreePIDs.InsertThreePID(ctx, txn, threepid, medium, localpart, domain)
+		return d.ThreePIDs.InsertThreePID(ctx, txn, threepid, medium, localpart, serverName)
 	})
 }
 
diff --git a/userapi/storage/sqlite3/account_data_table.go b/userapi/storage/sqlite3/account_data_table.go
index b8f125bdf..01ff6a8d3 100644
--- a/userapi/storage/sqlite3/account_data_table.go
+++ b/userapi/storage/sqlite3/account_data_table.go
@@ -37,13 +37,13 @@ CREATE TABLE IF NOT EXISTS userapi_account_datas (
     -- The account data content
     content TEXT NOT NULL,
 
-    PRIMARY KEY(localpart, room_id, type)
+    PRIMARY KEY(localpart, server_name, room_id, type)
 );
 `
 
 const insertAccountDataSQL = `
 	INSERT INTO userapi_account_datas(localpart, server_name, room_id, type, content) VALUES($1, $2, $3, $4, $5)
-	ON CONFLICT (localpart, room_id, type) DO UPDATE SET content = $4
+	ON CONFLICT (localpart, server_name, room_id, type) DO UPDATE SET content = $4
 `
 
 const selectAccountDataSQL = "" +
diff --git a/userapi/storage/sqlite3/accounts_table.go b/userapi/storage/sqlite3/accounts_table.go
index 6f855b1e8..861d794d9 100644
--- a/userapi/storage/sqlite3/accounts_table.go
+++ b/userapi/storage/sqlite3/accounts_table.go
@@ -34,7 +34,7 @@ const accountsSchema = `
 -- Stores data about accounts.
 CREATE TABLE IF NOT EXISTS userapi_accounts (
     -- The Matrix user ID localpart for this account
-    localpart TEXT NOT NULL PRIMARY KEY,
+    localpart TEXT NOT NULL,
     server_name TEXT NOT NULL,
     -- When this account was first created, as a unix timestamp (ms resolution).
     created_ts BIGINT NOT NULL,
@@ -45,9 +45,10 @@ CREATE TABLE IF NOT EXISTS userapi_accounts (
     -- If the account is currently active
     is_deactivated BOOLEAN DEFAULT 0,
 	-- The account_type (user = 1, guest = 2, admin = 3, appservice = 4)
-	account_type INTEGER NOT NULL
+	account_type INTEGER NOT NULL,
     -- TODO:
     -- upgraded_ts, devices, any email reset stuff?
+	PRIMARY KEY (localpart, server_name)
 );
 `
 
@@ -138,8 +139,8 @@ func (s *accountsStatements) InsertAccount(
 
 	return &api.Account{
 		Localpart:    localpart,
-		UserID:       userutil.MakeUserID(localpart, s.serverName),
-		ServerName:   s.serverName,
+		UserID:       userutil.MakeUserID(localpart, serverName),
+		ServerName:   serverName,
 		AppServiceID: appserviceID,
 		AccountType:  accountType,
 	}, nil
@@ -185,9 +186,7 @@ func (s *accountsStatements) SelectAccountByLocalpart(
 		acc.AppServiceID = appserviceIDPtr.String
 	}
 
-	acc.UserID = userutil.MakeUserID(localpart, s.serverName)
-	acc.ServerName = s.serverName
-
+	acc.UserID = userutil.MakeUserID(acc.Localpart, acc.ServerName)
 	return &acc, nil
 }
 
diff --git a/userapi/storage/sqlite3/devices_table.go b/userapi/storage/sqlite3/devices_table.go
index 95d92f45d..c5db34bd7 100644
--- a/userapi/storage/sqlite3/devices_table.go
+++ b/userapi/storage/sqlite3/devices_table.go
@@ -47,7 +47,7 @@ CREATE TABLE IF NOT EXISTS userapi_devices (
     ip TEXT,
     user_agent TEXT,
 
-		UNIQUE (localpart, device_id)
+	UNIQUE (localpart, server_name, device_id)
 );
 `
 
@@ -186,7 +186,7 @@ func (s *devicesStatements) DeleteDevices(
 	params[0] = localpart
 	params[1] = serverName
 	for i, v := range devices {
-		params[i+1] = v
+		params[i+2] = v
 	}
 	_, err = stmt.ExecContext(ctx, params...)
 	return err
diff --git a/userapi/storage/sqlite3/openid_table.go b/userapi/storage/sqlite3/openid_table.go
index 0201c39ba..f06429741 100644
--- a/userapi/storage/sqlite3/openid_table.go
+++ b/userapi/storage/sqlite3/openid_table.go
@@ -62,7 +62,7 @@ func (s *openIDTokenStatements) InsertOpenIDToken(
 	expiresAtMS int64,
 ) (err error) {
 	stmt := sqlutil.TxStmt(txn, s.insertTokenStmt)
-	_, err = stmt.ExecContext(ctx, token, serverName, localpart, expiresAtMS)
+	_, err = stmt.ExecContext(ctx, token, localpart, serverName, expiresAtMS)
 	return
 }
 
diff --git a/userapi/storage/sqlite3/profile_table.go b/userapi/storage/sqlite3/profile_table.go
index 4f01f3813..7b151adf6 100644
--- a/userapi/storage/sqlite3/profile_table.go
+++ b/userapi/storage/sqlite3/profile_table.go
@@ -30,12 +30,13 @@ const profilesSchema = `
 -- Stores data about accounts profiles.
 CREATE TABLE IF NOT EXISTS userapi_profiles (
     -- The Matrix user ID localpart for this account
-    localpart TEXT NOT NULL PRIMARY KEY,
+    localpart TEXT NOT NULL,
 	server_name TEXT NOT NULL,
     -- The display name for this account
     display_name TEXT,
     -- The URL of the avatar for this account
-    avatar_url TEXT
+    avatar_url TEXT,
+	PRIMARY KEY (localpart, server_name)
 );
 `
 
@@ -135,6 +136,7 @@ func (s *profilesStatements) SetDisplayName(
 ) (*authtypes.Profile, bool, error) {
 	profile := &authtypes.Profile{
 		Localpart:   localpart,
+		ServerName:  string(serverName),
 		DisplayName: displayName,
 	}
 	old, err := s.SelectProfileByLocalpart(ctx, localpart, serverName)
diff --git a/userapi/storage/sqlite3/threepid_table.go b/userapi/storage/sqlite3/threepid_table.go
index 2d3c7f2ee..2db7d5887 100644
--- a/userapi/storage/sqlite3/threepid_table.go
+++ b/userapi/storage/sqlite3/threepid_table.go
@@ -40,11 +40,11 @@ CREATE TABLE IF NOT EXISTS userapi_threepids (
 	PRIMARY KEY(threepid, medium)
 );
 
-CREATE INDEX IF NOT EXISTS account_threepid_localpart ON userapi_threepids(localpart);
+CREATE INDEX IF NOT EXISTS account_threepid_localpart ON userapi_threepids(localpart, server_name);
 `
 
 const selectLocalpartForThreePIDSQL = "" +
-	"SELECT localpart FROM userapi_threepids WHERE threepid = $1 AND medium = $2"
+	"SELECT localpart, server_name FROM userapi_threepids WHERE threepid = $1 AND medium = $2"
 
 const selectThreePIDsForLocalpartSQL = "" +
 	"SELECT threepid, medium FROM userapi_threepids WHERE localpart = $1 AND server_name = $2"
diff --git a/userapi/storage/storage_test.go b/userapi/storage/storage_test.go
index 79af7b853..23aafff03 100644
--- a/userapi/storage/storage_test.go
+++ b/userapi/storage/storage_test.go
@@ -377,7 +377,10 @@ func Test_Profile(t *testing.T) {
 
 		gotProfile, err := db.GetProfileByLocalpart(ctx, aliceLocalpart, aliceDomain)
 		assert.NoError(t, err, "unable to get profile by localpart")
-		wantProfile := &authtypes.Profile{Localpart: aliceLocalpart}
+		wantProfile := &authtypes.Profile{
+			Localpart:  aliceLocalpart,
+			ServerName: string(aliceDomain),
+		}
 		assert.Equal(t, wantProfile, gotProfile)
 
 		// set avatar & displayname