{"id":2238,"date":"2026-10-13T20:53:51","date_gmt":"2026-10-13T15:23:51","guid":{"rendered":"https:\/\/www.tiwaripedia.com\/index.php\/2026\/10\/13\/how-qr-codes-work\/"},"modified":"2026-10-13T21:18:35","modified_gmt":"2026-10-13T15:48:35","slug":"how-qr-codes-work","status":"publish","type":"post","link":"https:\/\/www.tiwaripedia.com\/index.php\/2026\/10\/13\/how-qr-codes-work\/","title":{"rendered":"How QR Codes Work: The Technology Behind Every UPI Scan"},"content":{"rendered":"<p><em>Last updated: October 2026 \u00b7 3 min read<\/em><\/p>\n<p>From paying the chaiwala by UPI to opening a restaurant menu, <b>QR codes<\/b> are everywhere in India. A QR (Quick Response) code is a two-dimensional barcode that a phone camera can read in a fraction of a second.<\/p>\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" loading=\"lazy\" width=\"1200\" height=\"675\" src=\"https:\/\/www.tiwaripedia.com\/wp-content\/uploads\/2026\/10\/how-qr-codes-work.png\" alt=\"Infographic: How QR Codes Work: The Technology Behind Every UPI Scan\" class=\"wp-image-2237\" srcset=\"https:\/\/www.tiwaripedia.com\/wp-content\/uploads\/2026\/10\/how-qr-codes-work.png 1200w, https:\/\/www.tiwaripedia.com\/wp-content\/uploads\/2026\/10\/how-qr-codes-work-300x169.png 300w, https:\/\/www.tiwaripedia.com\/wp-content\/uploads\/2026\/10\/how-qr-codes-work-1024x576.png 1024w, https:\/\/www.tiwaripedia.com\/wp-content\/uploads\/2026\/10\/how-qr-codes-work-768x432.png 768w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><figcaption>How QR Codes Work: The Technology Behind Every UPI Scan \u2013 infographic by Tiwaripedia<\/figcaption><\/figure>\n<h2>A short history<\/h2>\n<p>QR codes were invented in 1994 by Masahiro Hara at Denso Wave, a Japanese company, to track car parts. They are free to use, which helped them spread worldwide.<\/p>\n<h2>What is inside a QR code<\/h2>\n<ul><li><b>Three finder patterns<\/b> (big squares in corners) tell the camera where the code is and how it is rotated.<\/li><li><b>Alignment and timing patterns<\/b> help read codes that are bent or tilted.<\/li><li><b>Data modules<\/b>: the small black and white squares that store information as binary 1s and 0s.<\/li><li><b>Error correction<\/b>: extra data that lets the code work even if part of it is dirty or torn, up to about 30% at the highest level.<\/li><\/ul>\n<h2>How your phone reads it<\/h2>\n<ol><li>The camera spots the three finder squares.<\/li><li>Software straightens the image.<\/li><li>It reads the pattern of modules as bits.<\/li><li>Error correction fixes damaged bits.<\/li><li>The decoded text, such as a UPI payment link, is shown or opened.<\/li><\/ol>\n<h2>Why UPI uses QR codes<\/h2>\n<p>A UPI QR code contains a payment link with the merchant&#8217;s UPI ID and name, and sometimes a fixed amount. Shops need only a printed sticker, which made digital payments cheap enough for street vendors. Interoperable standards such as Bharat QR and UPI QR let one code work with all UPI apps.<\/p>\n<h2>Static vs dynamic QR<\/h2>\n<figure class=\"wp-block-table\"><table><thead><tr><th><\/th><th>Static QR<\/th><th>Dynamic QR<\/th><\/tr><\/thead><tbody><tr><td>Content<\/td><td>Fixed (UPI ID)<\/td><td>Changes per transaction (amount, order ID)<\/td><\/tr><tr><td>Used by<\/td><td>Small shops<\/td><td>Billing counters, online checkout<\/td><\/tr><tr><td>Amount<\/td><td>Customer types it<\/td><td>Pre-filled<\/td><\/tr><\/tbody><\/table><\/figure>\n<h2>How to avoid QR code scams<\/h2>\n<ul><li>You never need to scan a QR code or enter your PIN to <b>receive<\/b> money.<\/li><li>Check the payee name shown in your UPI app before paying.<\/li><li>Watch for stickers pasted over a shop&#8217;s real QR code.<\/li><li>Avoid scanning QR codes from unknown messages or posters offering prizes.<\/li><\/ul>\n<h2>Frequently asked questions<\/h2>\n<h3>How much data can a QR code hold?<\/h3>\n<p>Up to about 4,296 letters and numbers or 7,089 digits in the largest version, though most codes hold far less.<\/p>\n<h3>Do QR codes expire?<\/h3>\n<p>Static codes do not. Dynamic codes can be set to expire by the system that created them.<\/p>\n<h3>Can I make my own QR code?<\/h3>\n<p>Yes, many free generators exist. For UPI, download your official QR from your bank or UPI app.<\/p>\n<h2>Keep exploring<\/h2>\n<ul><li><a href=\"\/index.php\/2026\/10\/12\/how-upi-works\/\">How UPI works<\/a><\/li><li><a href=\"\/index.php\/2026\/10\/13\/incredible-facts-about-upi\/\">Facts about UPI<\/a><\/li><li><a href=\"\/index.php\/2026\/10\/13\/ai-in-banking-fraud-detection\/\">How AI stops payment fraud<\/a><\/li><li><a href=\"\/index.php\/category\/technology\/\">More Technology articles on Tiwaripedia<\/a><\/li><\/ul>\n<p><em>Facts are based on widely accepted official, scientific and historical sources at the time of writing. Spotted something that needs updating? <a href=\"\/index.php\/contact-us\/\">Let us know<\/a>.<\/em><\/p>","protected":false},"excerpt":{"rendered":"<p>How QR codes work: the squares, error correction and data inside, why UPI uses them, static vs dynamic QR codes and how to avoid QR code scams.<\/p>\n","protected":false},"author":1,"featured_media":2237,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"googlesitekit_rrm_CAow_YXIDA:productID":""},"categories":[6],"tags":[],"_links":{"self":[{"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/posts\/2238"}],"collection":[{"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/comments?post=2238"}],"version-history":[{"count":1,"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/posts\/2238\/revisions"}],"predecessor-version":[{"id":2505,"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/posts\/2238\/revisions\/2505"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/media\/2237"}],"wp:attachment":[{"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/media?parent=2238"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/categories?post=2238"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tiwaripedia.com\/index.php\/wp-json\/wp\/v2\/tags?post=2238"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}