Amazon has said it is struggling to keep up with demand for its voice-activated speaker system despite its best efforts.

The company has posted fiscal first-quarter earnings, reporting net revenue of $29.1 billion, whereas this time last year it recorded a $53 million loss. It also posted a net income of $513 million, or $1.07 a share, which is the most profit its ever seen during a quarter, and Amazon's CEO seems to think its devices are the reason why it is doing so well.

"Amazon devices are the top selling products on Amazon, and customers purchased more than twice as many Fire tablets than first quarter last year," Jeff Bezos, Amazon's CEO, said in a statement. "Echo too is off to an incredible start, and we can’t yet manage to keep it in stock despite all efforts. We’re building premium products at non-premium prices".

Despite the ill-conceived Fire phone from a few years ago, Amazon is becoming known as a stellar gadget-maker. The company stocks have soared based on today's results, and because it said demand for the Echo and other Amazon hardware products have caused them to fly off the shelves, although it wouldn't divulge actual product sales numbers.

However, the online retailer's most profitable business is still its Amazon Web Services cloud computing division, which posted a profit of $604 million and a revenue of $2.6 billion (a 64 per cent year-over-year increase). But not everything was on the up and up for Amazon. Its international business lost $121 million in operating income last quarter.

That whopping loss is still less than the $158 million it lost in the year-ago quarter. Also, keep in mind international revenue still grew to $9.57 billion from $7.75 billion, beating expectations. Wall Street analysts had expected Amazon to post earnings of 58 cents per share on $27.98 billion in revenue, according to a Thomson Reuters consensus estimate.

Amazon therefore completely toppled analysts' expectations. These quarterly results, which are for the period that ended on 31 March, mark the first time since 2012 that Amazon has turned a profit in four straight quarters. As a result, shares spiked more than 10 per cent in after-hours trading.