The full answer
Senior-only means the people writing your code have shipped products before. We do not staff projects with juniors learning on your budget, which is part of how we keep our standard: either we build it exceptional, or we don't.
The engineering lead owns the technical direction and is your main contact. Around them, the team typically includes frontend and backend or mobile engineers, a UI/UX designer and a QA engineer, with DevOps and AI specialists joining when the work needs them.
Our specialists are in-house, not freelancers assembled per project. They work across React, Next.js, Node.js, Python, Swift, Kotlin, Flutter, React Native and the major cloud platforms, and many have experience in the industry you operate in.
The team composition is described in your proposal, and the same people stay with the project through delivery wherever possible, so knowledge is not lost between phases.
For larger programmes, the team can grow as the project moves through phases, for example adding engineers when a second platform starts or AI specialists when a machine learning feature begins. Any change to team composition is discussed with you first, and the engineering lead remains your consistent point of contact.