Look first at relevant experience, not the length of the client list. Ask to see a couple of engagements that resemble your technology stack, and then find out whether those engineers are still with the blockchain software development company. A solid partner is happy to connect you with the tech lead. Vague answers at this stage generally mean the demo work came from somewhere else.

The contract deserves more attention than the sales deck. Three clauses do most of the work: assignment of intellectual property, the NDA, and notice periods and handover. Every artifact should transfer to you on payment, along with designs, scripts and infrastructure configuration. Look closely at wording that keeps framework code in the vendor's hands, because it is usually exactly the piece that locks you in.

Ask how they estimate. An honest estimate comes with a written set of assumptions, a breakdown per feature and a range rather than a single number. A fixed-price contract is only reasonable when the requirements are stable and documented; when the scope is still moving the provider pads the number and you pay for it anyway. Time and materials puts the risk on your side, hire vue storefront developer so it demands a cap, regular demos and transparent reporting.

How the work is run matters as much as team size. Establish what happens when the scope changes, who writes the acceptance criteria and how quality assurance works. A mature team should be able to show you a live build at the end of each sprint. Written acceptance criteria stay the practical protection against an argument at delivery time.

Before signing, plan for the handover while the relationship is still good. Insist that the source repository sits under your account from the first commit, and that the documentation is refreshed in every sprint. A partner who is comfortable with this will agree quickly; hesitation here reveals quite a lot.