Do you know if, all Credit Card companies charge their clients Foreign Currency Mark Up Fees for international online payment?

For HDFC CC, YES

Nearly all Credit Cards have forex fees, approximately 2-4% in general…. Yes First Exclusive CC is having one of the lowest, 1.75%; OneCard (IDFC powered CC) is also having the lowest as 1% (was 0% when it was originally launched).
As far as pre-paid cards are concerned; there are a couple of pre-paid cards like Niyo Global that have 0% forex.
And for Debit Card; Indusind Exclusive debit cards have 0% forex too,

I soemtime see payment option in rupeein foreign site will then there will be fees?

In SBI Card, forex fee will appear after 3 or 4 days as a separate entry in the statement.
For IndusInd cards, I think it is included as part of currency exchange rate. No extra fee is added after the transaction.

All chrgd

A few credit cards have high reward points so that their fx markup fee is more than covered by the value their reward points.

Only two (or three) credit cards of a high NRV bank accounts don’t have fx markup fee.

DCB Niyo card linked to your DCB savings account doesn’t have any Fx markup fee.

2 Indus debit cards don’t have fx markup fee.

Also, do note – Fx conversion RATE of Diners (is greater than) >RuPay/Discover >Amex > Visa > MasterCard – in that order. AND it is again different for different currencies!

@teriab33

Diners base conversion itself is around 0.70% more than MasterCard (tried & tested repeatedly).

Amex, Visa and Mastercard rate differential in negligible (10-20 paisa) till you are doing high value transactions. However, there is no card in Amex lineup which gives you less than 3.5% markup fee so that needs to be offset only by reward points.

Also, the only currency in which Visa gives you a better rate is Euro. Difference of Rs.50 per INR 100,000 spent. For all others, Mastercard is better (as of Feb, 2020).

Visa and MasterCard settle transactions as per the IST. Amex settles the transactions as per the EST/EDT time (true as of April, 2021) and IST is 9.5 hours ahead of EST/EDT. This would mean variation in conversion. Not sure about Diners.

Your day of transaction might be different from the day of settlement on part of merchant & that leads to conversion differential also.

Visa & MC have their conversion tools & calculators on site while Amex and Diners don’t.

Diners does have an App though as per its TnC of usage – Those rates are sourced from publicly available information and are not necessarily applicable to what Diners charges in Fx conversion. i found them to be marginally more than inter-bank rates. Again, this is only for reference while traveling/payment online.

Disclaimer: Forget all i mentioned above if you want to maintain your peace of mind.

@Ramta_Jogi good post, kg+ pending(can’t give it currently).