Paritas

Paritas is an Oracle-compatible database built on open-source PostgreSQL technology under the Apache-2.0 licence, developed by Tech Style Ltd for companies moving off Oracle. Its own page describes it as in development and states plainly that it is not yet for sale.

The approach starts from a problem that code converters do not catch: in some places PostgreSQL computes a different answer from Oracle for the same expression, without raising an error. Paritas is built around a differential test harness that runs Oracle, stock PostgreSQL and Paritas side by side, sends the same SQL to all three and compares every answer against Oracle. A difference counts only once it has been measured on a live engine. The page gives a measured example from August 2026, a floating-point expression past the top of its type, where Oracle returns infinity, PostgreSQL rejects the expression, and Paritas matches Oracle. It also lists open gaps, such as integer division, rather than claiming full compatibility.

According to the page, the harness runs, Paritas builds and installs, its regression suite passes at parity with upstream, and one fix has been accepted into the upstream open-source project, with further defects reported. Almost everything else is not built yet. Tech Style pairs it with pgrecon, an assessment tool for Oracle estates.