Begin with domain experience, not the size of the portfolio. Request a couple of projects that resemble your technology stack, and then find out who actually wrote that code. A serious vendor is happy to connect you with the people who would work on your project. Answers that name nobody at this stage usually mean the demo work came from somewhere else.

The paperwork warrants a slower read than the pitch. A few clauses carry most of the weight: ownership of the code, the NDA, and exit terms and handover. All the work product must transfer to you as it is paid for, along with designs, scripts and infrastructure configuration. Watch for language that leaves reusable components with the vendor, flutter consulting services because that is often the part you cannot replace later.

Ask how they estimate. A credible estimate arrives with a written set of assumptions, a breakdown per feature and a range rather than a single number. A fixed price works only when the requirements are stable and documented; otherwise the provider prices the risk in and you fund the buffer regardless. A time-and-materials model moves the risk back to the client, so it needs visible weekly reporting and a spending cap.

The delivery process matters as much as the number of developers. Establish how a new requirement enters the plan, who writes the acceptance criteria and how quality assurance works. A mature team should be able to walk you through a live build at the end of each sprint. Acceptance criteria in writing stay your only real protection against an argument at delivery time.

Finally, think about the day you no longer need this vendor while the relationship is still good. Require that the repository sits under your account from the beginning, crypto futures trading software development and that documentation is written as you go rather than left to the end. A partner who is comfortable with this will agree quickly; a long negotiation over it tells you a great deal.