Who builds it
Web app work is not the same as website work, and I will not pretend it is
Most BD clients looking for a web application development expert have been burned at least once. The story is almost always the same. A cheap team quoted 40,000 BDT. They delivered something that looked great in a demo on the project manager's laptop. Then it fell apart when three users logged in at once, or when the boss tried to export a report.
By the time you read this page, you already know the truth. A real application is not a WordPress theme with a contact form stuck on.
I am RH Fardin. I have spent the last five years building exactly this kind of software. My clients are Bangladeshi businesses, agencies, and a handful of overseas founders who hired me directly. I run the discovery call, write the data model, and design every screen. I write the backend, push the code, set up the server, and join the launch call.
There is no agency middle layer and no fresh junior practising on your project. There is no account manager turning your bug report into something the real coder will misread.
For you, that means something most agencies find awkward but is honest. You get one phone number, one inbox, and one person. That person can answer 'why did the invoice total round wrong last Tuesday' without booking a meeting. It also means I am picky. I take on a small number of app projects each quarter, because each one needs real architecture thinking, not a template swap.
If your idea is a simple form plus a database, I will tell you that. I will quote it in the 50,000 to 90,000 BDT range. A SaaS for many client companies is different. So is an internal operations tool with role-based access, attendance, reporting and SMS hooks. That is custom work, and it starts from 3,00,000 BDT.
You also get plain talk about cost. When a vendor quotes a web app in BDT, every shortcut shows up later, usually in your data. I would rather quote you honestly today and take 50% advance and 50% on launch. Then I ship something that still works two years from now. I will not win the deal on price and disappear when the bug list starts.
See pricing in BDT