In Jain Dharma, there are many types of fasts (upvās / tapa). Here is a simple list of the main ones:

Partial / daily-type fasts

1. Navkārsī – First food only after about 48 minutes from sunrise.
2. Porsī / Sādhporsī – First food after ~3 or ~4 hours from sunrise.
3. Ekasana – Only one meal in the whole day, in one sitting, usually before sunset.
4. Beasana (Biyasan) – Two meals in the day, in two fixed sittings, before sunset.
5. Ayambil – One very simple, almost tasteless meal in a day (usually no milk, curd, ghee, oil, sugar, fruits, rich spices, etc.).

Full‑day fasts

1. Upvās (Upavāsa) – No food for the whole day; usually only boiled water, and that too only during daylight (rules differ a bit by sangh/sect).
2. Tivihār Upvās – No food; water allowed only till sunset.
3. Chauvihār Upvās – No food or water after sunset till next sunrise (many keep the whole day this way).
4. Nirjal Upvās – No food and no water at all for the whole fast (very strict; done only with proper guidance).

Multi‑day fasts (longer tapasya)

1. Attham – 3 continuous days of fasting.
2. Atthai – 8 continuous days of fasting (often in Paryushan / Das‑Lakshan).
3. Sol‑bhatt / other long niyams – 16 or more days with special rules (varies by tradition).
4. Masakshaman – About one month of continuous fasting (very high tapa, done only by very strong sādhaks).
5. Varsitap (Varshi Tap) – Alternate‑day fasting, usually for 13 months 13 days (connected with Bhagwān Ṛṣabhdev’s one‑year fast).

Special observance fasts

1. Pausadha / Proshadhopvās – On special tithi (Ashtami, Chaturdashi, etc.) living like a sadhu/sadhvī for the day, usually with upvās or very little food.
2. Paryushan / Das‑Lakshan fasts – During these festivals many do Ayambil, Ekasana, Upvās, Attham, Atthai, etc., according to their capacity.

Final life‑vow

1. Sallekhanā / Santhārā – Gradual, peaceful, and voluntary reduction of food and water near the end of life, taken with full awareness, detachment, and guidance. This is not just “fasting” but a very high spiritual vow.

Difference in Shvetāmbara / Digambara

• Main idea is same – self‑control, karma‑nirjarā (shedding karma), and turning inward.
• Practical rules like whether boiled water is allowed, exact Ayambil items, etc., can differ. Always follow your local ācārya / sangh’s maryādā and your health.

If you want, you can read a detailed Q&A style explanation of Jain fasts here: