Getting existing systems to work with the new API was also a challenge at the World Bank, says Malarvizhi Veerappan, the bank's open data systems lead. Her group originally struggled with latency issues because their 8,000 economic indicators were not all directly linked to each another. It was important, she says, to create a structure that could incorporate all that historical data and grow as new information accumulated.
We didn't want the API to be a separate application. We wanted it to be part of everything else we did with the data. Malarvizhi Veerappan, open data systems lead, World Bank
"We didn't want the API to be a separate application. We wanted it to be part of everything else we did with the data," she says. "We needed to connect it back to our data system. It did require our improving our internal data system."
As the API grew, the team added performance monitoring and instituted policies to ensure good traffic flow. The organization also increased server capacity and added server redundancy to ensure availability of the API.
When financial information provider Bloomberg LP launched its Open Market Data Initiative in February 2012, the new open API — BLPAPI — was actually Version 3 of the software development kit the company had already been using internally, says Bloomberg CTO Shawn Edwards. In the old days, Bloomberg customers were given a dedicated terminal that connected them to the company's mainframe, which delivered market data, news and analysis.
Bloomberg's project has since evolved into a software package that customers install on their own systems. Even before making it open, the company used the API to develop specific applications that allow customers to manipulate Bloomberg data on their own desktops.
We're not in the business of selling software. We're going to win their business by providing the best services and the best data. Shawn Edwards, CTO, Bloomberg
With the launch of its open API, the company is now allowing customers to create their own apps, such as watch lists for selected securities or their own trading systems. It also allows outside developers to create apps that draw on other data sources besides Bloomberg's. "We're not giving away market data. What this allows people to do is integrate with other services," Edwards says. "The API is a piece of software that connects to the Bloomberg cloud."
It makes sense to let others do the app development, he explains. "We're not in the business of selling software," he says. "We're going to win their business by providing the best services and the best data."
When Bloomberg put out the open API, it decided to remove some of the features that the previous versions supported. There was discussion as to whether the API should be backward-compatible. "We said no," Edwards says. That meant some customers wound up with features that no longer worked, but Edwards says it makes the API less cluttered with obsolete functions.
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