where should I register my startup.USA/AUS?

You're thinking that you are instantly going to "create" so much interest that everybody is going to take notice and copy it. In realiy that may not happen.

Your best bet is get the MVP up and running pound the streets and phones in th easiest geo market available to you and prove that your target customer wants it, will pay for it and quickly work out the pitch and the on-boarding process.

While you are doing that - pitch US gyms via email and phone and try the same thing - see if the same applies, the rules of play are the same.

Keep this reasonably lo-level - Since the market is gym's their is no need to hype it just do under the radar direct "outbound" lead gen at those gyms. (No one will no what is going on). Use a product like Hubspot or Close.io to send emails and get responses for demos.

Sign up as many gyms as you can, get traction then if the money is pouring in worry about incorporation and the business side of things when that happens.

You can spend a lot of time worrying about the "what if this happens" when really what you should be worrying about...

"How am i going to make that happen"

And at this stage the 4 things you need to make happen are

1. a salable MVP product

2. customers burning your phones to pay for it.

3. a tried on-boarding process

4. a lead gen system to hit the gyms around the globe.

Don't get hooked up on fantasy instagram stories of how start-ups raise money and kill markets. If you hear a fantasy story that team has done their fair share of hard work, taking risks and making it happen before anyone heard about them.

Just go for it before your idea gets stale or you find out it was not such a great idea after-all.

For my first startup,I spent hours trying to figure this out on my own. After reading through hacker news and watching startup school lectures I decided that a c Corp registered in Delaware was a must. Then I contacted an attorney to tell him what I needed. During our 30 minute free consultation I learned that it didn’t really matter unless you are specifically looking to raise capital immediately with a venture capital firm and that changing or creating new corporate structures wasn’t that difficult or expensive. Speak to a lawyer who will listen to your needs and will tell you the best corporate structure for your business. Contact a lawyer that focuses on corporate law and has worked with early stage companies. I like interviewing lawyers from lawtrades, but be sure you select one that knows Australian federal law. Personally I would register in Australia if I were first pursuing Australian customers. If my business grew to a global stage then I’d speak to my lawyer to register in the best suitable location with the best tax incentives and legal structure.

From American companies such as Target going to Canada, Uber in China or Walmart in the foreign land of New York or even domestic companies that have tried to build horizontally—Microsoft with MP3 players or Google in social media—one thing is clear. You need to know your market. I’d suggest pursuing success at home first. Once you prove that you can move beyond.

Registration is not the issue. You should be thinking about where to launch. There are many US VCs who advise regional companies to launch and do it well there prior to launching in the US. If you build brand and get a better understanding of the product/market fit prior to coming to the US, you are a stronger candidate for investment. Do not make your worry over being copied your biggest concern; if the market is ready and as big as you think, you will be copied. If you are as good as you are, it will not matter.

Being in the US provides you no IP protection unless you have filed and received IP protection (patents/trademarks). Only being here does nothing. However, if you have a prior use of IP and another later tries to file, at minimum you are not blocked from use, and at best, you can block them from the registration/issue.