Do I have to pray in a mosque?

The earth itself was made a place of prayer, which is why a Muslim can pray in an office, an airport, or a field, and why the requirement is a clean spot rather than a consecrated one.

Praying alone is a valid, complete prayer. What congregation adds is reward: “The prayer in congregation is twenty seven times superior to the prayer offered by a person alone” (Sahih al-Bukhari 645). That is an encouragement of considerable weight, and it is why mosque attendance matters so much in practice — but it is a comparison between two valid prayers, not between a valid one and an invalid one.

The exception is Jumu‘ah, the Friday midday prayer, which replaces Dhuhr and is a gathering by definition: “O you who have believed, when the adhān is called for the prayer on the day of Jumuʿah Friday, then proceed to the remembrance of Allah and leave trade. That is better for you, if you only knew.” (Qur’an 62:9)

On Friday attendance is obligatory for men who are able; the scholarly discussion concerns who counts as excused — illness, genuine inability to leave work, distance, and similar. For women it is not obligatory, though they may attend and are not turned away.

Some practical notes for anyone praying outside a mosque:

• You need a clean place, not a prayer mat. A mat is convenience, not a condition.
• You face the qibla as best you can determine it. If you get it wrong after making a genuine effort, the prayer counts.
• A prayer at work in a stairwell or an empty meeting room is a real prayer. The Prophet’s ﷺ companions prayed on journeys, in tents and on the road.

If you can reach a mosque, there is real good in it beyond the reward — it is where you meet people who will teach you things no app can. But your prayer at home was never waiting on that.