Robinhood

Robinhood’s original iPhone app let individual investors open a brokerage account with no minimum balance and buy and sell stocks without paying a commission on each trade. The company has since expanded beyond stock trading to offer retirement accounts, crypto trading and digital banking.

Before founding Robinhood, Vlad Tenev and Baiju Bhatt sold trading software to hedge funds in New York. They saw how little large firms paid to trade stocks while most individual investors paid a commission on every trade. The two returned to California and started Robinhood in Palo Alto in 2013. When the app opened to the public in March 2015, the company reported that one in four customers had chosen Robinhood for their first investment account.

The trading day shaped how Robinhood’s engineers scheduled the batch processing behind services such as transaction statements and tax documents. In 2024, most of Robinhood’s Apache Spark jobs ran at night, when the clusters that handled customer traffic had capacity to spare. The team built that schedule into its job management service. After market close, the service could send new jobs to those clusters. Before the market opened, it switched routing back to dedicated analytics clusters, freeing capacity for the trading day.