System requirements
From TYPO3Wiki
Here is an overview about the requirements needed to use TYPO3:
- Operating System: Unix (e.g. Linux), Windows or Mac
- Web server: Apache, IIS
- Middleware: PHP5.2 (Note: Starting with TYPO3 4.6, all releases require PHP 5.3!)
- Database: MySQL 5.0 or any other database system supported by the TYPO3 DBAL (e.g. Oracle, Postgres and many others)(Note: Only some extensions feature full support for DBAL at this moment.)
- Hardware: A normal web server setup with a modern CPU and at least 256 MB RAM will do. As with all database-driven applications, more RAM is advisable though.
Keep in mind that many webspace-providers have a runtime-, memory- and cpu-load-limits set on their servers, preventing some parts of TYPO3 (Extension Manager, Indexed Search or some other extensions) to function as expected. Changing to a dedicated server or to a specialized TYPO3-hosting-environment can solve those problems.
You'll find the list originally at typo3.org.
Special requirements for the current versions of TYPO3 are available directly on the download page.