What are some electronic payment systems available for use by foreigners in India?

RBI has recently enabled UPI transactions for foreigners and NRIs. There are two players currently allowed by RBI to do this- one of them being Cheq.
Cheq allows to onboard using either indian or international number. Cheq creates a prepaid account, you can add money to this wallet using your international debit or credit cards.
This app helps you pay at any merchants using UPI. According to me, anyone coming to India should try this as it can help you skip cash handling in India and enables you to pay through UPI at any merchants.

Here’s the app download link:
https://link-to.app/cheq

TL;DR; as of 2019.04 for groceries find a supermarket and use Visa, MasterCard or Maestro.
For anything else rely on cash. To take out cash find ATM and use Visa, MasterCard or Maestro ‘without conversion’… Do not expect any ‘western’ mobile payment systems to be available…

I have been for 4 months now in India (2019.01-2019.04) mostly in Goa, however, I took a train to Nepal (Goraphur) and back, had stopped in Mumbai and New Delhi for a day, plus took a train from Kotch to Goa, so info is across few states (India is huge and I have no clue if following applies to all of the regions in country).

To buy tickets on Indian rail website online I had to use Revolut no other card (Barclays Visa, ING Maestro, Swedbank Mastercard) would work.

In major cities in supermarkets I have used the cards mentioned above and had no issues whatsoever, also in Goa (Colva) Kadgar SuperMarket I have used ING Maestro without a problem – this is the most cost-effective way to buy groceries. Find a supermarket and use Visa, MasterCard or Maestro.

For pretty much anything else, you will need cash. I was able to find ATMs around all train stations I have been to (don’t remember if Kochi had one). I didn’t take cash there though so no idea which of the cards would be accepted and not (I had train travel planned out with small denominations beforehand). However, in Goa all ATMs I have used would take my Maestro no problem, so one might assume it should work elsewhere too.
If you are offered by ATM to ‘do conversion’ when taking out cash always say ‘no’ or you will be hit +5 Eur on 10k rupees…

I couldn’t find anywhere where I could use Samsung Pay, Google Pay and similar ‘western’ mobile payment systems (could be I didn’t explore enough in New Delhi).

Hope this helps.

In India, if you have a valid and accepted ID proof (your Passport), you can get a working SIM within a few hours especially Airtel. Airtel is one of the leading operators in India so connectivity with that would not be an issue. There are other options as well that are mentioned here: What is a good Indian SIM for south to west coast (Kochi to Goa)?

Once you get a working mobile number, you can create a Paytm account for that number within minutes. Payments using Paytm are accepted almost everywhere in cities and towns. If you go hiking or to a remote village, then it’s quite possible they won’t be accepting Paytm as well. Also, payments using Paytm require a running data connection, which may not work in remote areas as well.

Loading your payTM account with money can be done electronically using credit cards. However, Foreign credit cards are not supported as per the PPI (Prepaid Payment Instruments) guidelines issued by the Reserve Bank of India

For Taxis, you can use payTM for Uber. Given the limitation of putting money in payTM account, I suggest you use your existing Uber account. If you already have an Uber account linked with your credit card (doesn’t matter which country you are living in) then you can use the same Uber account in India as well. The payments for that will be deducted from your currently linked card in INR and foreign exchange charges will be applied.

Talking about Ola cabs, it supports Ola money, the last time when I checked(in February) it did not accept international credit cards.

Warning: outdated answer

This answer was written during the 2016 Indian banknote demonetisation crisis, and many parts of the answer was written with that in mind. Moreover, there is extremely rapid technological and economic advancement in India, so everything else in this answer is also likely to be less and less accurate as time passes. I no longer live in India, and I will not update this answer as things change.

widely accepted for daily purchases

This doesn’t exist in India. There is lots of talk of starting to use systems so that people can give and recieve payments with their smartphones, but nothing has become widespread yet.

In larger cities and towns, some of the larger shops and businesses accept payment cards, but the great majority of businesses do not. This becomes even more true in smaller towns and rural areas, in which cash is typically the only way to pay.

One of the reasons for this is that Indian banks impose fees on card payments, and the business has to pay them. Of those that do accept cards, some don’t accept foreign cards.

I use PayTM myself. I think you do indeed need an Indian number to use it. And you need an Indian payment card or internet bank to load money into it. You might be able to load money into it at an office by paying cash, but that would defeat the purpose (cash being hard to get.)

Moreover, PayTM is not very widespread as a payment method in shops. It’s slightly more common in big cities, but not really something you can depend on.

My advice: Bring a foreign payment card (VISA or MasterCard/Maestro) with low fees on it and use it when you can. And get as much cash as you can somehow. You simply can not travel in India without cash. You can also bring some US dollars with you, to be used when paying large amounts. It might not be that hard to convince people to accept them for payments, given the current situation here. You might not get change on them, though. But they are great for emergencies.

Yes, getting cash is tricky these days. But ATMs are starting to open now. You may have to stand in line for a while when you find an ATM that is open, but it’s worth it to get the cash. A friend of mine with a German debit card stood in line the other day. There was a limit of 2000 per person, but she actually managed to do 8 withrawals and thus get 16.000. Appearantly the system didn’t stop her from making multiple withrawals since she had a foreign card. For more advice on getting cash, see this related answer.