In those cases where online transaction processing was not managed by specialized mainframe systems, the transaction processing was usually managed by a relational database manager. Unlike OpenTP1, however, a relational database manager usually manages only those transactions that affect databases controlled by the database manager. OpenTP1 manages transactions that might affect a variety of databases or resources: it is unrestricted in its scope and transaction-processing services.

OpenTP1 is a TP (transaction processing) monitor. In the computing industry, the term TP monitor has started to be used for software that provides full transaction-processing services: that is, software that can manage transactions in a wide variety of systems and is not restricted to managing updates of any single type of database. Unlike the restricted transaction processing services provided by a relational database manager, OpenTP1 provides a full suite of services to support online transaction processing. For example, OpenTP1 provides the means to recover not only from application failures but also from entire system failures. When linked with a relational database management system (RDBMS) OpenTP1 provides a high-speed and high volume data processing server.

OpenTP1 also provides program-development facilities including C, C++, and COBOL support, scheduling facilities, hot-standby systems, and load-balancing facilities.

When coding user application programs (UAPs), you can use C, C++, and COBOL, whichever is convenient for your engineering environment. When coding in C, you can use either the ANSI C, which predates ANSI, or K&R (B. Kernighan and D. Ritchie) format. When coding in COBOL, you can use either COBOL/2 or COBOL85.

You can use the data manipulation language (DML) you usually use with the host computer; so, in OpenTP1 systems you can use a familiar UAP development environment.