Senior Full-Stack Engineer: Build Scalable FinTech Apps

Gainbridge; United States; On-site; USD 150,000 - 210,000; Full time

Benefits offered by this job

Health, dental, and vision insurance

401K with company matching

Bonus programs

Job summary

Gainbridge, part of Group 1001, seeks a Senior Full Stack Software Engineer to build scalable frontend and backend solutions across acquisition, conversion, funding, and growth. You’ll collaborate with product and engineering leaders to deliver high‑quality customer experiences and mentor teammates while shaping engineering practices.

You will work across frontend and backend stacks, using React, Next.js, TypeScript, Kotlin/Java with Spring, and SQL databases, in a cloud environment with

Qualifications

• 5+ years of experience building production systems across frontend and backend.
• Proficiency with React, Next.js and TypeScript.
• Strong backend experience with Kotlin, Java, Spring, or similar.
• Experience building APIs and working with SQL databases.
• Understanding of distributed systems and asynchronous processing.
• Experience with AWS or GCP and containerized environments.
• Strong observability experience with Grafana, OpenTelemetry, or similar.
• Familiarity with AI tools in development workflows and agentic patterns.
• Experience with Kafka and event streaming in fintech products.

Responsibilities

• Build full stack solutions across frontend and backend systems, ensuring scalability, performance, and reliability in production.
• Develop user-facing applications using React, Next.js, and TypeScript.
• Design and implement backend services, APIs, and data models using Kotlin or Java with Spring.
• Work with SQL databases such as MariaDB, Postgres, or similar.
• Contribute to asynchronous and event-driven systems.
• Collaborate with product managers, designers, and engineers to drive technical decisions and deliver business outcomes.
• Own the software development lifecycle, including design, implementation, testing, and deployment.
• Ensure systems are observable through logs, metrics, and tracing.
• Contribute to building and improving agentic and AI-assisted development workflows using tools such as Claude.

Skills

React

Next.js

TypeScript

Kotlin

Java

Spring

SQL databases

AWS

GCP

Observability

Grafana

OpenTelemetry

Kafka

AI tools in development

Agentic patterns

Tools

MariaDB

Postgres

Job description

Gainbridge, part of Group 1001, seeks a Senior Full Stack Software Engineer to build scalable frontend and backend solutions across acquisition, conversion, funding, and growth. You’ll collaborate with product and engineering leaders to deliver high‑quality customer experiences and mentor teammates while shaping engineering practices.

You will work across frontend and backend stacks, using React, Next.js, TypeScript, Kotlin/Java with Spring, and SQL databases, in a cloud environment with