My wallet stayed home. My phone went everywhere.

Video: How QR code payments work in China's cashless economy.

Before my first trip to China, a friend asked me, “How much cash should I bring?”
“I don’t know,” I said. “Maybe a few hundred pounds?”
She laughed. “You won’t need it. Just your phone.”

I didn't believe her. In London, I use my phone for some things, like contactless payments on the Tube and ordering takeaway. But cash and cards are still everywhere. You can't buy a newspaper from a street vendor with Apple Pay. You can't pay for a bus ticket with a wave of your phone if you're not on a specific route.

So I packed my wallet anyway. I even went to the bank to get crisp new notes.

But on my first morning in Shanghai, I decided to try an experiment. I left my wallet in the hotel safe. I took only my phone and a photocopy of my passport just in case.

I walked to a convenience store. Picked up a bottle of water and a rice ball. The cashier pointed at a QR code. I opened Alipay (zhīfùbǎo), which I'd set up the night before using my foreign credit card. Scanned. The screen flashed "Payment successful: ¥9.80". That was it. No fumbling for coins, no signature, no PIN.

I felt a strange thrill. This is how they live every day.

Over the next two weeks, I pushed the experiment further.

I took a ride-hailing app (China's version of Uber) from my hotel to the Bund. The app charged me automatically. I didn't even have to press "pay". I ordered lunch from a dumpling shop through a food delivery app. Twenty minutes later, a scooter rider handed me a warm bag. I bought a high-speed train ticket from Shanghai to Hangzhou on my phone, with no ticket office, no queue, just a QR code on my screen.

By day four, I'd forgotten my wallet even existed.

The most surprising moment came in a small alley in Hangzhou. An old woman was roasting sweet potatoes in a charcoal drum. The smell was incredible. I asked how much. "Six yuan," she said. I pulled out my phone, expecting her to shake her head. Instead, she pointed to a faded QR code taped to the side of her cart. I scanned, paid with Alipay (zhīfùbǎo), and walked away with a steaming sweet potato.

That's when it hit me: this isn't just convenience. It's infrastructure. From a street vendor to a five-star hotel, from a museum ticket booth to a hospital registration desk, everyone, everywhere, expects you to pay with your phone.

One evening, I tried to find a limit. I booked a hotel room, ordered dinner, bought a ticket for a light show, paid for a shared bike, and sent money to a friend, all on my phone, all within an hour. No card swiped. No cash handed over.

Later, when I needed to split dinner with new friends, I used WeChat Pay (wēixìn zhīfù). They scanned my QR code, and the money appeared in my account instantly. No awkward "I'll get it next time", just seamless digital trust.

Back in London, after my trip, I went to a café. I automatically reached for my phone to pay. The cashier looked at me strangely. "Card or cash only," she said. I fumbled for my wallet. It felt clumsy, slow, old-fashioned.

I realised then: China hadn't just been a trip. It had reset my default.