Canadian merchants can now get hold of free Square card readers that plug into the headphone jack of an iPhone, iPad, or Android device and download the free Square Register app.

As well as accepting payments, the app also lets users track inventory, monitor daily reports and create customised loyalty and rewards programmes.

As in the US, the firm charges a transaction rate of 2.75% per swipe, with no hidden fees. Funds from payments are available the next business day.

Alyssa Cutright, VP, international, Square, says: "We are focused on making commerce easy for everyone. Square builds free tools for local businesses of all sizes and types to thrive. We're thrilled to introduce Canadian businesses and their customers to the most seamless and enjoyable way to do business."

Jack Dorsey's firm has seen huge growth over the last 18 months, making it the dominant player in the US app and dongle market, claiming more than two million users and $8 billion in payments processed a year. In September it closed a $200 million funding round, valuing the company at $3.25 billion.

However, while Square was first on the scene in the States, it arrives in Canada behind rivals PayPal Here and Intuit GoPayment and local entrant Axxess Payments.