The prostration of gratitude (sujud ash-shukr)

When Ka'b ibn Malik was pardoned after missing the Tabuk expedition, he immediately prostrated in gratitude (reported); the Prophet (may Allah's peace and blessings be upon him) prostrated at good news:

Whenever something happened that delighted him, he prostrated in gratitude to Allah.Abu Dawud 2774, judged good

The form

• A single prostration, outside prayer: saying the takbir ("Allahu akbar"), prostrating, saying "Subhana Rabbiya al-A'la" or any praise and gratitude, then rising.
• No fixed formula: no text fixed a single text: one praises and thanks freely; ablution is required per the majority (prayer fragment), Abu Hanifa excuses it.
• Without a two-rak'a prayer: gratitude prostration is a prostration, not a full prayer; some scholars preferred the two thanksgiving rak'as (reported of Ka'b): two lawful practices.
• Ibn Baz (Fatawa Nur ala ad-Darb, pp. 463-464): the gratitude prostration answers a general or personal blessing (a child's birth, an avoided accident); Abu Bakr prostrated at Musaylima's death; one says there what one says in the prayer's prostration; at the soundest view, purity is not required (the contrary view is judged unsupported).
• Dar al-Ifta Misriyya (Atiyya Saqr's fatwa, p. 43): a single prostration per the jumhur (Abu Bakra's hadith: Abu Dawud, Ibn Majah, at-Tirmidhi who judged it good); the prayer's conditions (purity, qibla, covering) apply there per the jumhur: takbir with intention, prostration then salam; the Malikis have no gratitude prostration: they prefer two rak'as; ash-Shawkani: no text requires purity for it.

Reported and recommended occasions

• Good news (birth, pardon, remission, useful success): the gratitude prostration is the prophetic answer to joy.
• Avoiding harm (avoided accident, healing): same practice, with recommended thanksgiving charity.
• Lawful business successes: thanksgiving and charity (the voluntary tenth on gains, reported of Companions as praiseworthy practice).

Status per schools

Recommended (sunna) per most jurists; some make it a simple lawful act; none forbids it: the gratitude prostration is among the Sunna's most accessible, sincerest gestures. It neither replaces nor delays an obligatory prayer: it adds to it.

Practical note

A mat, a takbir, a few seconds: the gratitude prostration is taught to children at the first good news. It is anti-arrogance: every success promptly returned to the One who gives it.