Begin with relevant experience, not the number of logos on the website. Request a couple of projects that resemble your technology stack, and then ask whether those engineers are still with the company. A solid partner will put you on a call with the people who would work on your project. Evasive answers at this stage generally mean the demo work came from somewhere else.
The contract warrants a slower read than the pitch. Three sections matter more than the rest: ownership of the code, confidentiality, and mobile app development services notice periods and handover. Everything produced must transfer to you once invoices are settled, along with documentation, pipelines and deployment scripts. Watch for language that leaves framework code with the vendor, because that is often the dependency that makes switching painful.
Find out how the estimate was built. 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 contract is only reasonable when the specification is complete; in any other case the vendor pads the number and you pay for uncertainty either way. A time-and-materials model puts the risk on your side, so it requires a sprint cadence, demos and php consulting services a budget cap.
The delivery process matters more than headcount. Establish how a new requirement enters the plan, who defines done and how quality assurance works. A team can walk you through running software rather than status reports. Acceptance criteria in writing stay the only reliable protection against an argument at delivery time.
Before signing, consider the handover while the relationship is still good. Ask that the code repository sits under your account from day one, and that the documentation is refreshed in every sprint. A partner who is comfortable with this accepts it without argument; resistance at this point tells you a great deal.
