Describe a website or app you find useful

The app I find most useful is M-Pesa. It's a mobile money service in Kenya, so you can keep money on your phone and send it to anyone with a phone number. Almost everybody in my country is using it, even people in small villages.

I found out about it when I was very young, because my parents used it all the time, but I started using myself when I was eighteen. My mother helped me to register with my ID card and then she showed me how to download the app.

Now I use it for nearly everything. I pay my rent with it every month, and I buy things at the small shop near my house without cash. Also, I use it to pay the fare in some matatus, which are minibuses in Nairobi. The most important thing is that I send money to my grandmother every month. She lives in Nyeri and she don't have a bank account.

I think it's very useful because it saves a lot of time. Before, my father had to stand in long queue at the bank or he sent money with the bus drivers, and sometimes it was lost. Now it takes few seconds. It's also more safe, because I don't need to carry cash in the city. For me, it's really changed the way how we live.

The app I'd find it hardest to manage without is M-Pesa, which is Kenya's mobile money service. Basically, your phone number works like a bank account, so you can pay for things or send money to anyone instantly, and it's used by pretty much everyone, from big supermarkets to tiny roadside kiosks.

I'd grown up watching my parents use it, but I only got my own account when I turned eighteen and could register a SIM card in my name. My mum walked me through the app that same afternoon, and I remember being slightly amazed that I could send money to someone in another town in about five seconds.

These days it handles most of my life. My rent goes out through it on the first of the month, I pay for groceries at the kiosk on my street by entering a till number, and some of the matatus, the minibuses we use in Nairobi, take it for fares too. But the thing I use it for most is sending money to my shosho, my grandmother, who lives in Nyeri and has never had a bank account in her life.

Why is it so useful? Mainly because it's replaced something slow and risky. When I was little, my dad used to queue for ages at the bank, or send cash upcountry with a bus driver and hope it arrived. Now it's instant, and it's much safer than walking around Nairobi with notes in your pocket. It's hard to explain to people from outside Kenya how much it has changed the everyday life.

The app I'd be genuinely lost without is M-Pesa, Kenya's mobile money service. In a nutshell, it turns your phone number into a wallet, so you can pay or send money to anyone in seconds, and it's so universal that everyone from a supermarket chain to the woman selling roast maize on my corner has a number you can pay into.

I can't really say I discovered it, because it's been part of the background of my life since primary school; my parents were using it before I could count. But I only opened my own account at eighteen, once I could register a SIM in my own name, and my mum sat me down that afternoon and talked me through the app. I still remember the slightly giddy feeling of sending money two hundred kilometres in the time it took to blink.

Now it quietly runs most of my finances. Rent leaves my account on the first of every month, I pay for groceries at the kiosk downstairs with a couple of taps, and a lot of matatus, Nairobi's minibuses, take fares through it. Above all, though, it's how I support my shosho, my grandmother, in Nyeri. She's never set foot in a bank, and she doesn't intend to start now.

What makes it so useful is how much hassle and risk it has removed. My father used to lose half a day queuing at the bank, or entrust an envelope of cash to a bus driver heading upcountry and simply hope for the best. Now the money lands before I've put my phone down, and I never have to walk through the city centre with a wad of notes in my pocket. It's one of those inventions you only appreciate when the network goes down.