"The Tanzania Revenue Authority (TRA) was established by Act of Parliament No. 11 of 1995, and started its operations on 1st July 1996. In carrying out its statutory functions, TRA is regulated by law, and is responsible for administering impartially various taxes of the Central Government."
The Tanzanian Revenue Authority provides Taxpayer Identification Numbers (TIN) for organisations registered in Tanzania. This is issued under section 3A(4) of the Income Tax Act no. 33 of 1973. As amended by the financial laws (miscellaneous amendments) 2000.
There is no searchable database for TIN. It's possible that a company with a TIN could be on the Tanzanian Business Registrations and Licensing Agency (BRELA) Online Registration System, which can be searched free of charge. It is worth checking list TZ-BRLA before deciding to use this list.