Start with domain experience, not the size of the portfolio. Request two or three case studies that match your domain and your stack, and then ask whether those engineers are still with the company. A solid partner is happy to connect you with the tech lead. Answers that name nobody at this stage almost always mean the demo work came from somewhere else.

The contract deserves a slower read than the pitch. Three clauses do most of the work: assignment of intellectual property, the NDA, and termination and handover. Every artifact must transfer to you on payment, including documentation, pipelines and deployment scripts. Be careful with wording that leaves reusable components in the vendor's hands, because it is usually the part you cannot replace later.

Ask how they estimate. An honest estimate arrives with a written set of assumptions, a task-level breakdown and an explicit range. A fixed price works only when the specification is complete; when the scope is still moving the vendor prices the risk in and you fund the buffer regardless. Hourly billing puts the risk on your side, so it requires a sprint cadence, demos and a budget cap.

The delivery process matters as much as the number of developers. Ask how a new requirement enters the plan, laravel vs wordpress who signs off on a feature and how quality assurance works. A dedicated development team services will be able to demonstrate running software rather than status reports. Written acceptance criteria are your only real protection against endless rounds of rework.

Finally, think about the end of the engagement while the relationship is still good. Insist that the code repository lives on infrastructure you own from the beginning, and that documentation is updated as part of the work. A partner who is comfortable with this accepts it without argument; a long negotiation over it says most of what you need to know.