Start with relevant experience, not the length of the client list. Request a couple of engagements that resemble your domain and your stack, and then ask whether those engineers are still with the company. A serious vendor will introduce you to the tech lead. Evasive answers at this stage almost always mean the delivery team is not the team you were shown.
The contract needs more scrutiny than the proposal. Three sections matter more than the rest: intellectual property assignment, the NDA, and termination and handover. All the work product has to transfer to you once invoices are settled, along with source code, designs and infrastructure as code. Watch for wording that keeps so-called reusable libraries in the vendor’s hands, since it is usually the dependency that makes switching painful.
Ask how they estimate. A serious estimate arrives with a written set of assumptions, a breakdown per feature and a best case and a worst case. A fixed-price contract is only reasonable when the requirements are stable and documented; in any other case the supplier adds a risk premium and you pay for it anyway. A time-and-materials model moves the risk back to the client, so it needs visible weekly reporting and outsource laravel development a spending cap.
Process beats the number of developers. Establish how a new requirement enters the plan, who writes the acceptance criteria and what the QA setup looks like. A well-run team will be able to show you a working build every one nearshore or offshore software development two weeks. Clear, written acceptance criteria are the practical protection against endless rounds of rework.
Last, plan for the day you no longer need this vendor before it becomes urgent. Ask that the source repository stays 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; resistance at this point tells you most of what you need to know.