Thousands of Swedes are having microchips implanted into their bodies so that they don't need to carry key cards, IDs, and even train tickets.\r\nAbout 3,000 people in Sweden have inserted a microchip \u2014 which is as tiny as a grain of rice \u2014 under their skin over the past three years,\u00a0Agence France-Presse reported. The technology was first used in the country in 2015.\r\nThe implants have already helped replace the need for a host of daily necessities. Ulrika Celsing's microchip, which is in her hand, has replaced her gym card and office key card. When she enters her workplace, the 28-year-old simply waves her hand near a small box and types in a code before the doors open, AFP said.\r\nLast year, the state-owned SJ rail line\u00a0started scanning the hands of passengers\u00a0with biometric chips to collect their train fare while on board. See how it works around the 2:24 mark in the video below.\r\nThere is no technological reason the chips couldn't also be used to buy things just like a contactless credit card, but nobody appears to have started testing that yet.\r\n'A slight sting'\r\nThe procedure is similar to that of a piercing and involves a syringe injecting the chip into the person's hand. Celsing, who obtained her injection at a work event, told AFP she felt just a slight sting.\r\nBut the chip implants could cause infections or reactions in the body's immune system, Ben Libberton, a microbiologist at MAX IV Laboratory in southern Sweden, told AFP.\r\nThis clip from 2015 shows a microchip being inserted into a person's hand:\r\nThe rise of 'biohacking'\r\nBiohacking \u2014 the modification of bodies with technology \u2014 is on the rise as more and more people start using tech wearables such as Apple Watches and Fitits.\r\nAbout four years ago, Swedish biohacking group Bionyfiken started organising "implant parties" \u2014 where groups of people insert chips into their hands en masse \u2014 in countries including the US, UK, France, Germany, and Mexico.\r\nSome\u00a050 employees\u00a0at Wisconsin vending-machine company Three Square Market voluntarily agreed to insert microchips into their hands, which they could then use to buy snacks, log in to computers, or use the photocopier.\r\n\r\nSwedes seem more willing to try the technology than most other nations.\r\nThe country's 10 million-strong population is generally more willing to share personal details, which are already recorded by the country's social-security system and readily available. According to AFP, people can find each others' salaries by simply calling tax authorities.\r\nMany of them also don't believe the microchip technology is advanced enough to be hacked. Libberton, the microbiologist, also said the data collected and shared by implants are too limited for users to fear hacking or surveillance.\r\nBionyfiken founder Hannes Sj\u00f6blad\u00a0told Tech Insider in 2015:\r\n"The human body is the next big platform. The connected body is already a phenomena. And this implant is just a part of it. [...]\r\n"We are updating our bodies with technology on a large scale already with wearables. But all of the wearables we wear today will be implantable in five to 10 years.\r\n"Who wants to carry a clumsy smartphone or smartwatch when you can have it in your fingernail? I think that is the direction where it is heading."