Letos is an open-source SQLite database administration and development tool designed to help users create, modify, query, and manage SQLite databases through a desktop application. Previously distributed as SQLiteStudio, the software provides a graphical interface for working with database tables, columns, indexes, views, triggers, and other database objects. Its SQL editor includes syntax highlighting, intelligent code suggestions, automatic formatting, error identification, and query execution tools to improve productivity. A built-in entity relationship diagram editor allows users to visually create database schemas, inspect relationships, and apply structural changes to existing databases. Letos supports multiple databases simultaneously and allows users to execute SQL queries that reference tables across different database files. Data browsing tools include editable grid and form views, column pinning, JSON editing, image previews, sorting, and filtering. Import and export functionality supports CSV, SQL, HTML, XML, PDF, and JSON formats, making it easier to transfer and analyze database information. The application also provides SQLCipher support, custom SQL functions, scripting through JavaScript, Python, and Tcl, and automated generation of sample database records. Letos is available for Windows, macOS, and Linux, with portable distributions, customizable interface settings, plugin support, and free licensing for personal and commercial use.