Full-Stack Developer (Next.js / TypeScript)

The Opportunity

KevInventions is a boutique technology consulting firm that builds and delivers software solutions for clients in fintech and SaaS. We’re bringing on a contract developer to embed directly on a client engagement—fixing critical infrastructure, shipping core features, and keeping a TypeScript-based web platform stable as it scales. This isn’t a ticket-taker role. You’ll be the person on the keyboard when it matters.

About KevInventions

KevInventions is a technology consulting firm specializing in AI and software development for fintech and SaaS clients. We work directly with founders and early-stage teams to build and stabilize their core platforms. Current work is on a fully TypeScript stack—Next.js frontend, mobile app, and backend API. We move fast and hold high standards for code quality.

About the Role

In the first 90 days, you’ll stabilize a broken authentication layer across web and mobile, build out a secure document-sharing feature, and own the web app front-to-back. Twelve months from now, you’ll have shipped multiple user-facing features and be the person we call when something’s on fire.

What You’ll Do

• Fix and unify the Firebase Auth integration across web and mobile so the platform is unblocked for all further development.
• Build a secure, role-based document sharing feature between end users and administrators.
• Own the Next.js web app (user-facing and admin portal), ensuring existing SEO, callbacks, and core functionality remain intact while new features ship.
• Maintain and extend the backend API, coordinating with the mobile app where shared functionality overlaps.
• Write clean, typed TypeScript—this is a typed codebase and you’ll be expected to keep it that way.
• Communicate blockers clearly and early—this is a contract role with direct stakeholder visibility.

What We’re Looking ForRequired:

• 3+ years of full-stack TypeScript development—web and backend.
• Hands-on experience with Next.js (not just React—we use the App Router and SSR patterns).
• Experience implementing or debugging Firebase Auth, including handling multi-platform auth flows.
• Experience with MongoDB for backend data persistence.
• Comfortable owning an entire feature from API schema to UI—front to back.
• US-based and set up for 1099 contract work (LLC or sole prop).

Preferred:

• Experience with secure file storage systems (S3, Dropbox API, or similar).
• Background building multi-user SaaS products with role-based access.
• Experience in fintech, accounting, or tax-adjacent products.
• Familiarity with NestJS or Node.js backend frameworks.

Compensation

$40–$50/hr depending on experience. This is a long-term contract engagement. Strong performers will have continued work as the platform scales.

How to Apply

Send a brief message with a link to a recent Next.js + TypeScript project (GitHub or live) and your availability. DM directly on LinkedIn or reach out via the contact info in our profile.