COBOL

Business-oriented programming language designed for data processing, file handling, and transactional systems. Executes on mainframes and open systems, with a readable, English-like syntax optimized for financial calculations and record-oriented workloads.

Over 800 billion lines of COBOL remain in production across banking, insurance, government, and healthcare. Major financial institutions and agencies run core systems on it. GnuCOBOL provides a free, cross-platform compiler used commercially, while Otterkit offers a modern open source compiler conforming to ISO COBOL 2023. Compared to general-purpose languages, it excels at fixed-point decimal arithmetic without rounding errors, sequential and indexed file processing, and long-lived batch jobs.

Notable capabilities:

• Native fixed-point decimal arithmetic suited for money and exact calculations
• Record-oriented file handling: sequential, indexed, and relative access
• Support for JSON and XML in modern compilers, with GnuCOBOL and Otterkit
• Integration with C, Java, and other languages via call conventions
• GnuCOBOL runs on Linux, BSD, macOS, and Windows with 19 COBOL dialects

Powers core banking, insurance claims, payroll, government benefits, and batch processing. Developers modernize legacy systems with transpilers that convert COBOL to Go or Java, or extend them using web frameworks like cobol-on-wheelchair for CGI and FastCGI. VS Code extensions and GnuCOBOL’s gdb integration support debugging and IDE workflows.