diff --git a/src/docker-config.php b/src/docker-config.php
index 7b810be..8d6dd9d 100644
--- a/src/docker-config.php
+++ b/src/docker-config.php
@@ -2,14 +2,14 @@
 
 // Rename it to config.php before using in docker.
 
-if (getenv('MTT_DB_TYPE') == 'mysql') {
-    define("MTT_DB_TYPE", "mysql");
-    define("MTT_DB_HOST", getenv('MTT_DB_HOST'));
-    define("MTT_DB_NAME", getenv('MTT_DB_NAME'));
-    define("MTT_DB_USER", getenv('MTT_DB_USER'));
-    define("MTT_DB_PASSWORD", getenv('MTT_DB_PASSWORD'));
-    define("MTT_DB_PREFIX", getenv('MTT_DB_PREFIX'));
-    define("MTT_DB_DRIVER", getenv('MTT_DB_DRIVER'));
+if (getenv('MTT_DB_TYPE') == 'mysql' || getenv('MTT_DB_TYPE') == 'postgres') {
+    define("MTT_DB_TYPE", getenv('MTT_DB_TYPE'));
+    define("MTT_DB_HOST", getenv('MTT_DB_HOST') ?: "undefined_host");
+    define("MTT_DB_NAME", getenv('MTT_DB_NAME') ?: "undefined_db");
+    define("MTT_DB_USER", getenv('MTT_DB_USER') ?: "undefined_user");
+    define("MTT_DB_PASSWORD", getenv('MTT_DB_PASSWORD') ?: "");
+    define("MTT_DB_PREFIX", getenv('MTT_DB_PREFIX') ?: "mtt_");
+    define("MTT_DB_DRIVER", getenv('MTT_DB_DRIVER') ?: "");
 }
 else if (getenv('MTT_DB_TYPE') == 'sqlite') {
     define("MTT_DB_TYPE", "sqlite");
diff --git a/src/includes/class.db.postgres.php b/src/includes/class.db.postgres.php
new file mode 100644
index 0000000..776c557
--- /dev/null
+++ b/src/includes/class.db.postgres.php
@@ -0,0 +1,208 @@
+<?php declare(strict_types=1);
+
+/*
+    This file is a part of myTinyTodo.
+    (C) Copyright 2023 Max Pozdeev <maxpozdeev@gmail.com>
+    Licensed under the GNU GPL version 2 or any later. See file COPYRIGHT for details.
+*/
+
+// ---------------------------------------------------------------------------- //
+class DatabaseResult_Postgres extends DatabaseResult_Abstract
+{
+    /** @var PDOStatement */
+    protected $q;
+
+    /** @var int */
+    protected $affected;
+
+    /** @var string  const */
+    protected $schema = 'public';
+
+    function __construct(PDO $dbh, string $query, bool $resultless = false)
+    {
+        // use with DELETE, INSERT, UPDATE
+        if ($resultless)
+        {
+            $this->affected = (int) $dbh->exec($query); //throws PDOException
+        }
+        // SELECT
+        else
+        {
+            $this->q = $dbh->query($query); //throws PDOException
+            $this->affected = $this->q->rowCount();
+        }
+    }
+
+    function fetchRow(): ?array
+    {
+        $res = $this->q->fetch(PDO::FETCH_NUM);
+        if ($res === false || !is_array($res)) {
+            return null;
+        }
+        return $res;
+    }
+
+    function fetchAssoc(): ?array
+    {
+        $res = $this->q->fetch(PDO::FETCH_ASSOC);
+        if ($res === false || !is_array($res)) {
+            return null;
+        }
+        return $res;
+    }
+
+    function rowsAffected(): int
+    {
+        return $this->affected;
+    }
+}
+
+// ---------------------------------------------------------------------------- //
+class Database_Postgres extends Database_Abstract
+{
+    const DBTYPE = 'postgres';
+
+    /** @var PDO */
+    protected $dbh;
+
+    /** @var int */
+    protected $affected = 0;
+
+    protected $dbname;
+
+    function __construct()
+    {
+    }
+
+    function connect(array $params): void
+    {
+        $host = $params['host'];
+        $user = $params['user'];
+        $pass = $params['password'];
+        $db = $params['db'];
+        $options = array(
+            PDO::PGSQL_ATTR_DISABLE_PREPARES => 1,
+            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
+        );
+        $this->dbname = $db;
+        $this->dbh = new PDO("pgsql:host=$host;dbname=$db", $user, $pass, $options);
+    }
+
+
+
+    /*
+        Returns single row of SELECT query as indexed array (FETCH_NUM).
+        Returns single field value if resulting array has only one field.
+    */
+    function sq(string $query, ?array $values = null)
+    {
+        $q = $this->_dq($query, $values);
+
+        $res = $q->fetchRow();
+        if ($res === false || !is_array($res)) {
+            return null;
+        }
+
+        if (sizeof($res) > 1) return $res;
+        else return $res[0];
+    }
+
+    /*
+        Returns single row of SELECT query as dictionary array (FETCH_ASSOC).
+    */
+    function sqa(string $query, ?array $values = null): ?array
+    {
+        $q = $this->_dq($query, $values);
+        $res = $q->fetchAssoc();
+        if ($res === false || !is_array($res)){
+            return null;
+        }
+        return $res;
+    }
+
+    function dq(string $query, ?array $values = null) : DatabaseResult_Abstract
+    {
+        return $this->_dq($query, $values);
+    }
+
+    /*
+        for resultless queries like INSERT,UPDATE,DELETE
+    */
+    function ex(string $query, ?array $values = null): void
+    {
+        $this->_dq($query, $values, true);
+    }
+
+    private function _dq(string $query, ?array $values = null, bool $resultless = false) : DatabaseResult_Abstract
+    {
+        if (null !== $values && sizeof($values) > 0)
+        {
+            $m = explode('?', $query);
+            if (sizeof($m) < sizeof($values)+1) {
+                throw new Exception("params to set MORE than query params");
+            }
+            if (sizeof($m) > sizeof($values)+1) {
+                throw new Exception("params to set LESS than query params");
+            }
+            $query = "";
+            for ($i=0; $i<sizeof($m)-1; $i++) {
+                $query .= $m[$i]. $this->quote($values[$i]);
+            }
+            $query .= $m[$i];
+        }
+        $this->lastQuery = $query;
+        $dbr = new DatabaseResult_Postgres($this->dbh, $query, $resultless);
+        $this->affected = $dbr->rowsAffected();
+        return $dbr;
+    }
+
+    function affected(): int
+    {
+        return $this->affected;
+    }
+
+    function quote($value): string
+    {
+        if (null === $value) {
+            return 'null';
+        }
+        return $this->dbh->quote((string) $value);
+    }
+
+    function quoteForLike(string $format, string $string): string
+    {
+        $string = str_replace(array('\\','%','_'), array('\\\\','\%','\_'), $string);
+        return $this->dbh->quote(sprintf($format, $string)). " ESCAPE '\'";
+    }
+
+    function like(string $column, string $format, string $string): string
+    {
+        $column = str_replace('"', '""', $column);
+        return '"'. $column. '" ILIKE '. $this->quoteForLike($format, $string);
+    }
+
+    function lastInsertId(?string $name = null): ?string
+    {
+        $ret = $this->dbh->lastInsertId();
+        if (false === $ret) {
+            return null;
+        }
+        return (string) $ret;
+    }
+
+    function tableExists(string $table): bool
+    {
+        $r = $this->sq("SELECT 1 FROM information_schema.tables WHERE table_catalog = ? AND table_name = ?",
+                        array($this->dbname, $table) );
+        if ($r === false || $r === null) return false;
+        return true;
+    }
+
+    function tableFieldExists(string $table, string $field): bool
+    {
+        $r = $this->sq("SELECT 1 FROM information_schema.columns WHERE table_name = ? AND column_name = ? AND table_schema = ?",
+                        array($table, $field, $this->schema) );
+        if ($r === false || $r === null) return false;
+        return true;
+    }
+}
diff --git a/src/init.php b/src/init.php
index ea8a145..89ca472 100644
--- a/src/init.php
+++ b/src/init.php
@@ -116,6 +116,31 @@ function configureDbConnection()
         $db->dq("SET NAMES utf8mb4");
     }
 
+    # PostgreSQL Database
+    else if (MTT_DB_TYPE == 'postgres')
+    {
+        require_once(MTTINC. 'class.db.postgres.php');
+        $db = DBConnection::init(new Database_Postgres());
+        try {
+            $db->connect([
+                'host' => MTT_DB_HOST,
+                'user' => MTT_DB_USER,
+                'password' => MTT_DB_PASSWORD,
+                'db' => MTT_DB_NAME,
+            ]);
+        }
+        catch(Exception $e) {
+            $errlog = "Failed to connect to PostgreSQL database: ". $e->getMessage();
+            if (MTT_DEBUG) {
+                logAndDie($errlog);
+            }
+            else {
+                logAndDie("Failed to connect to database", $errlog);
+            }
+        }
+        $db->dq("SET NAMES 'utf8'");
+    }
+
     # SQLite3 Database
     elseif (MTT_DB_TYPE == 'sqlite')
     {
diff --git a/src/setup.php b/src/setup.php
index 51a854b..ea3bccc 100644
--- a/src/setup.php
+++ b/src/setup.php
@@ -77,22 +77,28 @@ if ($configExists)
     // Determine current installed db version
     $ver = databaseVersion($db);
 
-    if ($ver == '1.4') {
+    if ($ver == '') {
+        // clean install
+        // will not load settings from database in init.php
+        Config::$noDatabase = true;
+    }
+    else if (version_compare($ver, '1.4') < 0) {
+        // Very old or previously failed while install
+        exitMessage(htmlspecialchars("Can not update. Unsupported database version ($ver)."));
+    }
+    else if ($ver == '1.4') {
         // Need to upgrade. Do not ask for old password
         require_once(MTTPATH. 'db/config.php');
         Config::loadConfigV14($config);
         unset($config);
         DBConnection::init($db);
     }
-    else {
-        if ($ver == '') {
-            Config::$noDatabase = true; //will not load settings from database in init.php
-        }
-        require_once('./init.php');
-        if ( !is_logged() ) {
-            die("Access denied!<br> Disable password protection or Log in.");
-        }
+
+    require_once('./init.php');
+    if ( !is_logged() ) {
+        die("Access denied!<br> Disable password protection or Log in.");
     }
+
 }
 
 if ($ver == '')
@@ -102,7 +108,7 @@ if ($ver == '')
     if ($install == '' && $db !== null)
     {
         # We already have settings file and need to create tables.
-        exitMessage("<form method=post>Click next to create tables in '". htmlspecialchars($dbtype). "' database.<br><br>
+        exitMessage("<form method=post>Click next to create tables in ". htmlspecialchars(databaseTypeName($db)). " database.<br><br>
                     <input type=hidden name=stoken value='$setupToken'>
                     <input type=hidden name=install value=create>
                     <input type=submit value=' Next '></form>");
@@ -114,9 +120,10 @@ if ($ver == '')
             <form method=post>Select database type to use:<br><br>
             <input type=hidden name=install value=config>
             <input type=hidden name=stoken value='$setupToken'>
-            <label><input type=radio name=db_type value=sqlite checked=checked onclick=\"document.getElementById('mysqlsettings').style.display='none'\">SQLite</label><br><br>
-            <label><input type=radio name=db_type value=mysql onclick=\"document.getElementById('mysqlsettings').style.display=''\">MySQL</label><br>
-            <div id='mysqlsettings' style='display:none; margin-left:30px;'><br><table>
+            <label><input type=radio name=db_type value=sqlite checked=checked onclick=\"document.getElementById('dbsettings').style.display='none'\"> SQLite</label><br><br>
+            <label><input type=radio name=db_type value=mysql onclick=\"document.getElementById('dbsettings').style.display=''\"> MySQL</label><br><br>
+            <label><input type=radio name=db_type value=postgres onclick=\"document.getElementById('dbsettings').style.display=''\"> PostgreSQL (beta)</label><br>
+            <div id='dbsettings' style='display:none; margin-left:30px;'><br><table>
             <tr><td>Host:</td><td><input name=db_host value=localhost></td></tr>
             <tr><td>Database:</td><td><input name=db_name value=mytinytodo></td></tr>
             <tr><td>User:</td><td><input name=db_user value=mtt></td></tr>
@@ -129,9 +136,12 @@ if ($ver == '')
     {
         check_post_stoken();
         # Save configuration
-        $dbtype = ($_POST['db_type'] == 'mysql') ? 'mysql' : 'sqlite';
+        $dbtype = $_POST['db_type'] ?? '';
+        if ($dbtype != 'mysql' && $dbtype != 'postgres' && $dbtype != 'sqlite') {
+            exitMessage("Unknown database type $dbtype");
+        }
         Config::set('db.type', $dbtype);
-        if ($dbtype == 'mysql') {
+        if ($dbtype == 'mysql' || $dbtype == 'postgres') {
             Config::set('db.host', _post('db_host'));
             Config::set('db.name', _post('db_name'));
             Config::set('db.user', _post('db_user'));
@@ -240,12 +250,15 @@ function createAllTables($db, $dbtype)
     if ($dbtype == 'mysql') {
         createMysqlTables($db);
     }
+    else if ($dbtype == 'postgres') {
+        createPostgresTables($db);
+    }
     else {
         createSqliteTables($db);
     }
 }
 
-
+/* ===== mysql ========================================================= */
 function createMysqlTables($db)
 {
     $db->ex(
@@ -324,6 +337,78 @@ function createMysqlTables($db)
 }
 
 
+/* ===== postgres =============================================== */
+function createPostgresTables($db)
+{
+    $db->ex(
+"CREATE TABLE {$db->prefix}lists (
+    id INTEGER NOT NULL GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+    uuid CHAR(36) NOT NULL default '',
+    ow INTEGER NOT NULL default 0,
+    name VARCHAR(250) NOT NULL default '',
+    d_created INTEGER NOT NULL default 0,
+    d_edited INTEGER NOT NULL default 0,
+    sorting SMALLINT NOT NULL default 0,
+    published SMALLINT NOT NULL default 0,
+    taskview INTEGER NOT NULL default 0,
+    extra TEXT
+) ");
+    $db->ex("CREATE UNIQUE INDEX {$db->prefix}lists_uuid ON {$db->prefix}lists (uuid)");
+
+    $db->ex(
+"CREATE TABLE {$db->prefix}todolist (
+    id INTEGER NOT NULL GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+    uuid CHAR(36) NOT NULL default '',
+    list_id INTEGER NOT NULL default 0,
+    d_created INTEGER NOT NULL default 0,
+    d_completed INTEGER NOT NULL default 0,
+    d_edited INTEGER NOT NULL default 0,
+    compl SMALLINT NOT NULL default 0,
+    title VARCHAR(250) NOT NULL default '',
+    note TEXT default NULL,
+    prio SMALLINT NOT NULL default 0,
+    ow INTEGER NOT NULL default 0,
+    duedate DATE default NULL
+) ");
+    $db->ex("CREATE INDEX {$db->prefix}todo_list_id ON {$db->prefix}todolist (list_id)");
+    $db->ex("CREATE UNIQUE INDEX {$db->prefix}todo_uuid ON {$db->prefix}todolist (uuid)");
+
+    $db->ex(
+"CREATE TABLE {$db->prefix}tags (
+    id INTEGER NOT NULL GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+    name VARCHAR(250) NOT NULL DEFAULT ''
+) ");
+    $db->ex("CREATE UNIQUE INDEX {$db->prefix}tags_name ON {$db->prefix}tags (name)");
+
+    $db->ex(
+"CREATE TABLE {$db->prefix}tag2task (
+    tag_id INTEGER NOT NULL,
+    task_id INTEGER NOT NULL,
+    list_id INTEGER NOT NULL
+) ");
+    $db->ex("CREATE INDEX {$db->prefix}tag2task_tag_id ON {$db->prefix}tag2task (tag_id)");
+    $db->ex("CREATE INDEX {$db->prefix}tag2task_task_id ON {$db->prefix}tag2task (task_id)");
+    $db->ex("CREATE INDEX {$db->prefix}tag2task_list_id ON {$db->prefix}tag2task (list_id)");
+
+    $db->ex(
+"CREATE TABLE {$db->prefix}settings (
+    param_key   VARCHAR(250) NOT NULL default '',
+    param_value TEXT
+) ");
+    $db->ex("CREATE UNIQUE INDEX {$db->prefix}settings_key ON {$db->prefix}settings (param_key)");
+
+    $db->ex(
+"CREATE TABLE {$db->prefix}sessions (
+    id          VARCHAR(64) NOT NULL default '',
+    data        TEXT,
+    last_access INTEGER NOT NULL default 0,
+    expires     INTEGER NOT NULL default 0
+) ");
+    $db->ex("CREATE UNIQUE INDEX {$db->prefix}sessions_id ON {$db->prefix}sessions (id)");
+}
+
+
+/* ===== sqlite =============================================== */
 function createSqliteTables($db)
 {
     $db->ex(
@@ -364,7 +449,7 @@ function createSqliteTables($db)
     $db->ex(
 "CREATE TABLE {$db->prefix}tags (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
-    name VARCHAR(50) NOT NULL DEFAULT '' COLLATE UTF8CI
+    name VARCHAR(250) NOT NULL DEFAULT '' COLLATE UTF8CI
 ) ");
     $db->ex("CREATE INDEX tags_name ON {$db->prefix}tags (name)"); //NB: unique in mysql
 
@@ -515,12 +600,31 @@ function testConnect(&$error)
                 if (!defined($c)) throw new Exception("$c is not defined");
             }
 
-            $db->connect( array(
+            $db->connect([
                 'host' => MTT_DB_HOST,
                 'user' => MTT_DB_USER,
                 'password' => MTT_DB_PASSWORD,
                 'db' => MTT_DB_NAME
-            ));
+            ]);
+        }
+        else if (MTT_DB_TYPE == 'postgres')
+        {
+            if (!defined('PDO::PGSQL_ATTR_DISABLE_PREPARES')) {
+                throw new Exception("Required PHP extension 'PDO_PostgreSQL' is not installed.");
+            }
+            require_once(MTTINC. 'class.db.postgres.php');
+
+            foreach (['MTT_DB_HOST', 'MTT_DB_USER', 'MTT_DB_PASSWORD', 'MTT_DB_NAME', 'MTT_DB_PREFIX'] as $c) {
+                if (!defined($c)) throw new Exception("$c is not defined");
+            }
+
+            $db = new Database_Postgres;
+            $db->connect([
+                'host' => MTT_DB_HOST,
+                'user' => MTT_DB_USER,
+                'password' => MTT_DB_PASSWORD,
+                'db' => MTT_DB_NAME
+            ]);
         }
         else if (MTT_DB_TYPE == 'sqlite')
         {
@@ -535,7 +639,9 @@ function testConnect(&$error)
             }
             require_once(MTTINC. 'class.db.sqlite3.php');
             $db = new Database_Sqlite3;
-            $db->connect( array( 'filename' => MTTPATH. 'db/todolist.db' ) );
+            $db->connect([
+                'filename' => MTTPATH. 'db/todolist.db'
+            ]);
         }
         else {
             throw new Exception("Unsupported database type: ". MTT_DB_TYPE);
@@ -566,6 +672,17 @@ function myExceptionHandler($e)
     exit;
 }
 
+function databaseTypeName(Database_Abstract $db)
+{
+    $s = get_class($db);
+    switch ($s) {
+        case "Database_Mysql": return "MySQL";
+        case "Database_Postgres": return "PostgreSQL";
+        case "Database_Sqlite3": return "SQLite";
+        default: return $s;
+    }
+}
+
 
 ### update v1.4 to v1.7 ##########
 function update_14_17(Database_Abstract $db, $dbtype)