Full Stack Developer for a Fintech SaaS Audit (Next.js, Node.js, React Native)

We run a live fintech platform for small and medium businesses. It has a web app and a mobile app, and both have grown quickly. Before we build more features, we want an experienced developer to review the main flows and tell us what to fix first. Stack: Next.js and React web app, React Native mobile app, Node.js backend, PostgreSQL, third-party API integrations. What we need: A review of the main web app flows and the Node.js API A review of the React Native app and how it shares the API with the web app A look at how the code works with PostgreSQL and how the integrations are built A check of the basics for a financial product: authentication, access to user data, handling of errors in key flows A short list of the biggest risks, ordered by priority, with practical next steps This is a limited audit, not a rewrite. We will share repo access and the key user flows after the contract starts. Budget: fixed price, $500 for about 10 to 12 hours. Please tell us in your proposal how you would approach it.