PriorArtCheck: Pre-Filing & Freedom-To-Operate Landscape Search for Hardware Founders

I dont know when should I start prototype development, before or after doing the patent?

Prototype first, almost every time. The version of the idea in your head right now is not the version that survives building it and showing it to people, and if you file before that, you usually end up patenting features that turn out not to matter while the thing that actually makes it work gets discovered later, outside your filing. Patents written before market feedback are the easiest ones to design around, because they protect what you guessed was important instead of what is. The bigger reframe though: the fear of showing the idea too early is almost always backwards. Ideas don't get stolen at the sketch stage, nobody with the ability to execute your idea has the time to, and the graveyard of failed products is full of well-protected inventions nobody wanted. Talking to potential customers early is how you find out whether there's anything worth patenting at all. Execution and distribution are the moat, a patent is paperwork that occasionally backs the moat up. If the disclosure worry still nags you, there's a cheap release valve: a provisional filing costs very little, stamps your date, and buys a year to validate loudly before deciding whether the real patent is worth real money. File the provisional the week before you go public if it helps you sleep. But get the idea in front of people — that's the step that decides everything else, and it's the one most first-timers delay for exactly the wrong reason.

Patent research comes before prototype development, but that's different from filing a patent. For example, I know that rabbit product design does patent research as the first step in their process, before any design work starts, so you know whether the landscape has white space and whether you can legally build it before money goes into development. On actually filing your own patent, the stats are rough, most applications get rejected first pass, litigation averages around three million dollars if someone copies you, and a good engineer can work around most patents anyway