Twenty years ago, I wrote a Python component that integrates with IBM-MQ and uses a response structure in IBM COBOL/DB2. It accesses DB2 data and a VSAM database to return a huge string to be structured on a screen of an e-commerce website for a Brazilian airline. Twenty years ago… It was the beginning of my journey into high-end computing and what they call the cloud, and I never imagined that, in 2025, this language created in the 1950s would still support the backbone of the digital economy. It still supports a lot!
COBOL alive !
While Python, JavaScript, and Go dominate the headlines, COBOL continues to process trillions of dollars a day. Quietly, with the same reliability as ever.
In the 1950s, programming was chaotic. Each manufacturer had its own language, and changing machines required rewriting everything from scratch. That's when the US Department of Defense called on industry and academia to create a common, readable, and portable language. COBOL (Common Business Oriented Language) was born, with the brilliant Grace Hopper championing the idea that code should look like English, not math. Imagine???
The result? A language any business analyst could read and that quickly became the universal language of corporate mainframes.
From the 1960s to the 1980s, COBOL reigned supreme in banks, governments, and large corporations. At its peak, 80% of the world's business systems were written in it. Today, in the midst of the AI era, the numbers are still impressive, with estimates indicating that between 220 and 850 billion lines of COBOL remain active. US$3 trillion is processed every day using COBOL code, and 95% of ATMs and 80% of card transactions depend on it. In 2022, in the US alone, banks spent US$36.7 billion on legacy system maintenance, a figure expected to exceed US$57 billion by 2028!
What explains this longevity? Several factors, such as stability and performance: COBOL systems are robust and virtually immune to failure. The cost of replacement, as rewriting millions of lines is risky and extremely expensive, is high. And the embedded knowledge, when much of the business rules live solely within these systems.
Far from being a museum piece, COBOL has evolved. Recent versions support object orientation, JSON, XML, and REST APIs. Today, it runs on hybrid clouds, communicates with Java, Python, and C#, and can be accessed via microservices. The trend isn't to erase COBOL, but to encapsulate, refactor, and integrate it, preserving decades of business logic with new digital layers.
COBOL isn't seen on tech conference stages, but it holds the stage. And the fact that COBOL is still here, 65 years later, is perhaps the greatest testament to software engineering the world has ever seen, coexisting with JS, Python, and Java! To those new to the market, I hope one day to see the legacy operating as it does today.
Think, the MAINFRAME concept is today CLOUD Computing !
