A core Islamic practice of giving, Sadaqah has been defined as an act of "giving something without seeking a substitute in return and with the intention of pleasing God, expecting a reward either on the earth or on the hereafter or expiation of sins or removal of something bad that may have happened in the future".
The only 2 differences between Sadaqah & zakat are that Zakat is an obligation and must be paid, whilst Sadaqah is optional, the second difference is zakat can only be given to a select number of groups, while Sadaqah is open to wider recipients.
Sadaqah is formed from a tri-literal Arabic word for Sincerity and Truth. Hence Sadaqah is a physical act of truth and sincerity in God and expecting all good from Him in return and purification from sins Examples of Sadaqah
1. Feeding & Clothing others
2. To be just between different parties and disputes
3. To smile when meeting others especially the spouse
4. Being kind to animals, caring for and feeding them
5. Donating to someone in need (especially vulnerable groups, although donating without judging)
6. Shielding someone from something harmful
7. Visiting and caring for the sick
8. Giving directions to someone in need
9. A good word
10. Every step was taken towards the prayer or Mosque
11. Supporting disabled
12. To alleviate debt
This is just a particular form of Sadaqah, with the word Jariyah (Perpetual), meaning a reward that is perpetual and long-lasting, good examples of Sadaqah Jariyah:
1. To teach and educate
2. Build an institute, schools, mosques, orphanages, hospital, etc
3. Build or sustain a means of provision, fruit trees, water well
4. Building a Shelter for Humans or Animals
5. Investing in something that has longevity and a noble cause
In some Islamic cultures, the sacrifice of an animal (sheet, goat etc) is also seen as aform of Sadaqah, although this is definetely a form, the end result being to feed the needy.