The phrase "as its first customer" is correct and usable in written English.
You can use it when referring to the initial user or client of a product or service.
Example: "The company launched its new software last week, and I am proud to say that I signed up as its first customer."
Alternatives: "as the initial client" or "as the inaugural user".
Last month, Lucent signed Global Crossing as its first customer.
The service is being promoted on YouTube via a video featuring Seinfeld character George Costanza, who poses as its first customer.
TuVox signed up Handspring as its first customer about two months ago, and expects other clients, including the video game maker Activision, to begin turning on their systems soon.
In the 1980s, he asked, "Why not be a research and development shop, an extended arm for companies in the U.S. and Europe?" Wipro won Motorola and Intel as its first customers.
The plan, according to co-founder and CEO Tal Tamir, will be to use this latest Series B funding to work on that next stage of the business: figuring out how to produce its chips at scale and at a competitive price point versus other solutions like RFID tags, as well as secure its first customers.
Small customers of the problem-tracking software led to bigger customers, such as American Airlines in 2002, its first customer that paid online without ever talking to Atlassian.
Optimizely made today's announcement as part of OptiCon, its first customer conference.
And with Google as its first major customer, it looks like Frogmetrics may be on its way to replacing those annoying receipt codes once and for all.
In April, the startup unveiled a Shopify-like solution for retailers called Built by b8ta, with Netgear as one of its first customers.
And remarkably for a company trying to break into the home furnishing market, it landed furniture goliath IKEA as its first real customer; GrokStyle's point-and-search functionality is being added to the IKEA Place AR app.
The Demonstrator will be a human piloted, 1/3 scale prototype of the eventual 45-passenger jet craft it aims to use for commercial service, with Virgin Galactic as its first paying customer for planes.
