If I am a developer and built my app but no big marketing budget. Is the app will just die in peace?

A failed Product Hunt launch is not the end of your product, it's just the beginning rather. I looked at the app you've built and have just one thing to say: reach out to Amazon sellers. Collect a list of A-list (top), B-list and C-list sellers in a spreadsheet with emails, contact names, product category, etc. Reach out to them one-by-one, personalize your offer for each one of them (don't offer big discounts right away; free trials are ok). Also browse the web and look for Amazon seller groups on Facebook, Reddit, various forums, etc. Don't do too much at once though, set yourself a small daily goal, e.g. "Reach out to 5 sellers today", so you don't burn out too quickly and have time to analyze & tweak your approach. Like Andrey said, it's a marathon, not a sprint. Those looking to "get rich quick" are always first to lose, so be patient and make a plan for how to out-live your competition.

@hosam_ayman is this a theoretical or you have something to sell me? For instance I would like to sell you our product Uclusion for your development project management and communication. Uclusion is two founders on a limited budget and so we are relying on communities like this to find early adopters. We certainly are not looking to die in piece :-).

Building apps is a long-term game. You never know what works best and what gains traction. My advice is to think of some niche communities that might be interested in your product - reddit subreddits, discord channels, personal blogs, and try to get your initial user base that way. But keep in mind that I'm not an experienced product builder, just starting out as well, so I might be wrong