Open with the business problem, not a feature list. Which people will use the system, with what frequency, and how is the job done today? An experienced team who understands the goal often proposes a cheaper route to it; one who only sees the requirements as given can only price your assumptions along with the work.
Set out the scope as concrete flows: custom blockchain development who does what, and what happens next. Every bit as useful, write down what is out of scope. A written out-of-scope list prevents more disagreement later than any other single page. Also mark which parts are firm and which may still change — the difference changes the price, and concealing the open questions helps nobody.
List the constraints. This means existing systems the software has to talk to, the data you already hold and its condition, security and compliance rules, expected load, target platforms and infrastructure that is already decided. If a deadline is real, say why: an experienced team can often resequence the work to hit it, but not if the date is a secret.
Say what done means for the important items. Clear acceptance criteria do not need formal language: a short paragraph setting out what a user should be able to do is enough. That one addition reduces acceptance testing considerably and closes off the usual argument at handover.
Finally, ask for a specific format. Request an itemised estimate, laravel alternatives the assumptions behind each number, the risks the team sees and an optimistic and a pessimistic figure. Treat a wide range as useful information rather than evasion: it tells you where your description is thin. At that point rewrite that part and ask for a new estimate — the next version tends to be the one worth planning around.
