Look first at domain experience, not the size of the portfolio. Ask for three or four projects that match your domain and your stack, and then ask specifically whether those engineers are still with the best laravel development company. An honest provider will put you on a call with the engineers. Answers that name nobody at this stage usually mean you are talking to a reseller.
The contract needs more scrutiny than the proposal. Three clauses do most of the work: assignment of intellectual property, non-disclosure, laravel developers for hire and exit terms and handover. All the work product has to transfer to you once invoices are settled, together with source code, designs and infrastructure as code. Be careful with wording that leaves reusable components outside the transfer, as that is often the dependency that makes switching painful.
Find out how the estimate was built. A credible estimate comes with a written set of assumptions, a breakdown by feature or module and an explicit range. 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 it anyway. Time and materials moves the risk back to the client, so it demands visible weekly reporting and a spending cap.
How the work is run beats the number of developers. Establish how change requests are handled, who signs off on a feature and what is rag and langchain the QA setup looks like. A team can show you running software rather than status reports. Clear, written acceptance criteria stay your only real protection against an argument at delivery time.
Last, plan for the day you no longer need this vendor while the relationship is still good. Require that the code repository stays on infrastructure you own from the beginning, and that a readme and architecture notes are kept current as the code changes. A partner who is comfortable with this will agree quickly; hesitation here tells you quite a lot.