Briefer is an open-source data platform that allows users to run SQL and Python code, transforming notebooks into dashboards and data applications. It supports connections to various data sources, such as Postgres, BigQuery, Redshift, and enables the direct use of query results in Python code blocks. Additionally, it features pre-installed libraries and an integrated AI assistant to help users write code faster. The dashboard and data application functionalities of Briefer empower users to create interactive pages for data exploration and decision support.