Kiwi cloud software firms are shouting their successes after Xero signed up its 500,000th customer and Auckland retail software-maker Vend struck a marketing deal with Apple.

Xero's milestone, which it announced at its Xerocon conference in Denver, Colorado, puts it halfway towards what founder Rod Drury has previously described as its "medium-term goal" of signing up a million customers. At the conference, Drury demonstrated how customers could manage their accounts from Apple's smart watch using Xero's software.

Also overnight on Wednesday, Vend said it was one of the companies that Apple said it would work alongside. Apple chief financial officer Luca Maestri announced during a briefing on its second-quarter financial results that it would help market "innovative mobile solutions" from about 24 firms for use with its iPad tablet computers.

Vend chief executive Vaughan Rowsell said it was one of the chosen firms and described the agreement as the "strongest validation" of its cloud software system to date.

Vend's software is used by 15,000 retailers in 140 countries, in some cases to let them run their checkout systems on iPads rather than on computers attached to conventional tills.

Rowsell said Vend expected its customer numbers to increase significantly as a result of Apple's sales support, although the details of the assistance Apple would provide were confidential.

Vend is privately-owned but has raised more than $30 million from investors.

The company was given an additional boost on Wednesday when the Wall Street Journal mentioned its software as an example of the cloud software systems that were being adopted by small US businesses.

The newspaper interviewed one of Vend's customers, TopShelf Style, on how the software had let it run its fashion business from a mobile truck.

Completing the loop, Xero said it was working with Vend and US company, Deputy, which produces cloud-based rostering software, to deliver an "unmatched retail-focused solution for small businesses".

A third Kiwi cloud software company, VMob, also received an international endorsement this week when its mobile marketing system won the "Cloud Platform: Application Innovation" award at Microsoft's Worldwide Partner awards in Orlando, Florida.

VMob extended a deal with McDonald's earlier this year under which the fast food chain will use VMob's platform to send promotions to customers' smartphones in the US and other new markets.

Microsoft received 2300 nominations for the 43 awards that were up for grabs. VMob, which listed on the junior NZAX exchange, plans to list on the Australian stock exchange later this year.