Does it work like cryptocurrnecy tumblers? If yes, wouldn't it be hard for you to establish your project because you can almost do the same with those tumblers, and what makes yours unique from the other.
How do you plan to get an income from this because it looks like it is only a bridge for anonymous payments, do you get commisions or are you putting ads, cause that helps a lot.
One last thing I can think of is how can the receiver get the payment when there are no sign up, this might be a problem in the long run because there can be mix-ups, I hope you can put a unique identifier for receiving payments like two way encryption where the sender and the receiver carries one key and the payment will never be valid when there is no activation from the both parties.
Thanks for your comments, answering your questions:
Does it work like cryptocurrency tumblers?Not exactly, payrobot.io has two approaches:
1) Payment forwardingThis is like a cryptocurrency tumbler, you send coins to one address and receive it in other. BUT, this is intended for payment tracking via API and Callbacks, example:
Tom opens a Bitcoin platform and wants to accept payments easily, he doesn't want to use BitPay, Coinbase, or Full Node etc because of (any reason: hard implementation, privacy, sign-up, high rates, etc). So with payrobot.io generates one-time addresses to give to his clients and receive payments. Payrobot notifies his platform with url callbacks the status of payments so he can manage them automatically. Furthermore funds are sent immediately to his personal coin address as soon as payment is confirmed.
2) WalletSame as above but payments are stored in a private wallet where Tom's platform can request later send coins to different addresses. For example this is useful if Tom is implementing a PTC platform, investing, games or whatever where send coins to clients is required.
How do you plan to get an income from this because it looks like it is only a bridge for anonymous payments?Payrobot.io takes 0.90% fee per recieved payment (inbound transactions), all outbound transactions are free. No ads

One last thing I can think of is how can the receiver get the payment when there are no sign up, this might be a problem in the long run because there can be mix-upsGenerated addresses are one-time use so there is no way to mix-up where the payment has to be forwarded, all transactions are identified with unique IDs also
It is a nice thing that you respond to questions, now that I can a clear picture of your project, here is another question for you:
Wouldn't your project be a hotbed for illicit transactions? The anonymity surely will attract people from all walks of life, and I think that the creator has a degree of responsibility when a transaction for illegal has been done on his site.
Do you have any sort of audit trail that can only be given to authorities when the time comes? I know that this defeats the purpose of anonymity but I believe that letting illegal activities become prolific side by side with cryptocurrency innovation will result in a pyrrhic victory. Will your site participate with authorities for investigation when it is needed?