Square was established in 2009 by Jack Dorsey and Jim McKelvey as a payment-services company for businesses and individuals.
Its first major product was a small card reader that plugged into a mobile device. The device allowed sellers who might not have qualified for traditional merchant-processing equipment to accept card payments.
Square’s focus on transparent tools and mobile checkout made it especially useful to small retailers, market vendors, cafés, and independent service providers. The company later expanded into invoicing, payroll, point-of-sale software, lending, and online commerce.
Square is now part of Block, Inc., the corporate name adopted by its parent company in 2021. The Square brand continues to refer to the company’s seller-focused business products.