Observing the evolution of the economy in real time and high definition can be essential when evaluating the economic impact of an event with few precedents in the world economy like the current Covid19 crisis. Although it is not the first or the last time we are faced with a disaster, expected or unexpected, the characteristics of this one make it almost unique. That is why an accurate diagnosis of “what, how, when and where” is quite important. The analysis of granular data in real time with Big Data helps us precisely to solve most of these questions and, consequently, allows economic agents, institutions and policymakers to have quick and precise answers for decision making. Every day, banks, payments systems providers, and other financial intermediaries record and store massive amounts of individual transaction records arising from the normal course of economic life. Financial and payments systems throughout the world generate a vast amount of naturally occurring, and digitally recorded, transaction data, but national statistical agencies mainly rely on surveys of much smaller scale for constructing official economic series. This paper considers data transactions from credit- and debit card data from BBVA, the second largest bank in Spain and also with a major market presence in numerous other countries, as an alternative source of information for measuring consumption, a key component of GDP. Particularly, we process more than 6 billion transactions collected from BBVA cardholders and BBVA-operated point-of-sale terminals from seven countries, 2.1 billion of which arise in Spain. We analyze the data along three different dimensions: as a coincident indicator for aggregate and subnational consumption; as a detailed household consumption survey; and as a mobility index. While card spending growth is more volatile than non-durable consumption growth, normalized spending correlates strongly with official consumption measures. In the cross section, patterns in card spending match those in official household budget surveys very closely. The implication is that card spending can stand in for consumption surveys in environments where official data is not available, for example due to reporting delays or to insufficient geographic or household detail. We apply the idea of card spending as a consumption survey to the COVID-19 crisis in Spain, where we present four findings: (1) a strong consumption reaction to lockdown and its easing at the national and regional levels; (2) a rapid, V-shaped consumption recovery in the aggregate; (3) an adjustment to the average consumption basket during lockdown towards the goods basket of low-income households; (4) a divergence in mobility patterns during lockdown according to income in which poorer households travel more during the workweek. Exploring the relation between mobility and disease incidence, we show that in the absense of direct mobility proxies, card transactions in transportation categories can be used as a mobility proxy at narrow geographical and socioeconomic status levels of analysis. Therefore, our main conclusion is that transaction data provides high-quality information about household consumption, which makes it a potentially important input into national statistics and research on household consumption, as well as for the business and policymakers, to have rapid and accurate responses about what is happening in real time and measure the impact of COVID-19 and the policy interventions made to limit its spread.