Hallow's accessible language introduces different methods of prayer, along with inspiring talks, guides to spiritual practices and notifications to encourage users to set goals and stay on track.
As a priest, I know that helping people develop healthy prayer habits is important. But both as a scholar of Christian spirituality and as someone who provides spiritual direction to others, I see limitations in what prayer apps can achieve.
Churches have long adopted communications technology enthusiastically to spread their message. The Reformation started by Martin Luther and his followers in 16th-century Germany spread rapidly through the use of Gutenberg's printing press.
Currently, Catholic faith-based media include the Eternal Word Television Network, founded by Catholic nun Mother Angelica, which provides news, radio programming, live-streamed services and web-based religious instruction to an estimated viewership of more than 250,000,000 viewers.
The kind of community that technology fosters is an important spiritual question to consider, however. Evidence suggests that the unstoppable reach of technology into all aspects of our lives is shaping how people think and relate to one another. Research has shown that while people have far more access to information, their attention span is less. Since prayer involves both the mind and emotions, this has spiritual implications.
An embodied community asks people to show up regularly in real time and gather together with those they may not know well or even like. The time-consuming inconvenience and lack of choice are in fact spiritual riches because they involve the needs of others. This kind of sacrifice is not what prayer apps facilitate.
In the Catholic tradition, prayer is not primarily about finding peace, joy or reducing stress. Those can be achieved, but they aren't always present or necessary. Deepening one's prayer is often a slow process that involves passing through periods of being bored, distracted or frustrated.
People with excellent intentions can sometimes end up being confused about what they are experiencing in prayer, especially if it is unfamiliar. As a priest, I tell people a good rule of thumb is that growth in prayer leads to greater kindness to others, and less focus on oneself.
Many religious traditions, within and outside Christianity, insist that healthy spiritual growth can be aided by the personal guidance of people more experienced in prayer.
The "spiritual father" in monasticism is a teacher of prayer. Within Catholicism, spiritual directors, who can be laypeople or ordained, listen to people talk about their experiences in prayer, helping them relate their prayer to their everyday lives. While this tradition of spiritual guidance can help provide guidance, each person's prayer is always unique to them.
Even the best-designed algorithms are unlikely to tend to the human soul adequately.
Hallow's many enthusiastic reviews insist that this prayer app is a force for good. So do the many users of other apps.
From my perspective, the measure of a prayer app's success is not the number of downloads. Jesus insists on looking at the fruit of good intentions. If any app helps people to be more patient, humble, just and attentive to the poor, it's a good thing. But being an active member of a real community is likely needed as well.
Dorian Llywelyn is president of the Institute for Advanced Catholic Studies, USC Dornsife College of Letters, Arts and Sciences.