Open with the reason this kotlin software development company should exist, not your preferred technology. What kind of user will use this, how often, and how is the job done today? A vendor who understands the goal often proposes a simpler way to reach it; one who only sees the requirements as given prices the list as written.
Set out the scope as user stories or scenarios: who does what, and what happens next. Every bit as useful, list what the first release deliberately excludes. An explicit exclusion list prevents more argument later than the rest of the brief combined. Mark too which items are decided and hire developers in eastern europe which may still change — estimators price uncertainty, and pretending everything is fixed only hurts you.
List the constraints. The list covers the platforms and services involved, the data you already hold and its condition, regulatory obligations, expected load, which devices matter and stacks you cannot change. If a deadline is real, say why: a team is usually able to resequence the work to hit it, but only if they know it exists.
Say what the word done means for the important items. Testable acceptance criteria need not use special syntax: a plain-language note setting out what a user should be able to do will do. This one section shortens acceptance testing by a surprising margin and removes the most common source of disputes.
To close, say what you expect back. Request an itemised estimate, the assumptions behind each number, the risks the team sees and an optimistic and a pessimistic figure. Treat a wide range as information, not evasion: it usually points to the part of the brief that needs work. At that point tighten that section and ask for a new estimate — the second estimate tends to be the one worth planning around.
