New City Catechism

New City Catechism, developed by Timothy Keller and The Gospel Coalition, adapts the great Reformation catechisms into 52 memorable questions and answers on the core doctrines of the Christian faith. Its logic is simple and time-tested: you cannot defend what you have not first internalized, and the app is built to help you actually learn and retain sound doctrine. Each of the 52 questions pairs a question and answer with a supporting Scripture, a short prayer, a commentary video or written meditation, and, for children, a kid-friendly song, so the same content works for a five-year-old and a fifty-year-old alike.

The execution is excellent. The app is genuinely beautiful, calm, and uncluttered, with both a shorter children's answer and a fuller adult answer, plus an interactive two-person mode that makes it easy to catechize a child or a friend. It is free, doctrinally careful, and warmly ecumenical within historic Protestant orthodoxy. The honest caveat is one of category: this is catechesis and discipleship, not apologetics in the debate-and-defense sense. You will emerge grounded in what Christians believe and why, but you will not find rebuttals to atheism, arguments for the resurrection, or engagement with skeptics here.

Understood on its own terms, it is close to ideal. As the foundation beneath your apologetics, a firm grasp of the doctrines you are defending, it is hard to imagine a more thoughtful, more accessible, or better-designed free tool. Families, new believers, and anyone wanting to shore up their doctrinal footing should install it happily, then reach for a dedicated apologetics resource when the goal shifts from knowing the faith to defending it.