Start with relevant experience, not the length of the client list. Ask for two livewire or alpine js three engagements that resemble your domain and your stack, and then find out who actually wrote that code. An honest provider is happy to connect you 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 needs more attention than the sales deck. Three clauses do most of the work: assignment of intellectual property, confidentiality, and termination and handover. Every artifact must transfer to you on payment, together with designs, scripts and infrastructure configuration. Watch for language that leaves so-called reusable libraries in the vendor’s hands, because that is often the part you cannot replace later.
Ask how they estimate. An honest estimate is accompanied by a written set of assumptions, a breakdown per feature and a best case and a worst case. A fixed-price contract only makes sense when the specification is complete; otherwise the supplier adds a risk premium and you pay for it anyway. A time-and-materials model shifts that risk to you, rag development company so it requires a sprint cadence, demos and a budget cap.
The delivery process matters more than headcount. Find out how change requests are handled, who writes the acceptance criteria and blockchain development company what the QA setup looks like. A team should be able to show you a working build every one or two weeks. Clear, written acceptance criteria remain the only reliable protection against an argument at delivery time.
Finally, think about the handover while the relationship is still good. Require that the repository lives in your organisation from the first commit, and that the documentation is refreshed in every sprint. A provider confident in its own work says yes immediately; hesitation here says a great deal.