Principal Engineer 

Our client is a fast growing series B fintech head quartered in NYC.  They are passionate about helping every small business in America.  

As a  Principal Engineer you will own and drive large technical initiatives end to end. This role is ideal for someone who thrives in startup environments, is comfortable working with high autonomy, and can take an idea from a vague business problem all the way to a scalable, production-grade system. You will act as the technical owner for key initiatives—setting direction, making architecture decisions, writing critical code, and ensuring successful delivery without requiring heavy oversight.

Responsibilities

• Own full-stack initiatives end to end—from problem definition and architecture to implementation, deployment, and production support.
• Define and execute the technical strategy and roadmap aligned with fast-moving startup goals
• Design and build scalable, secure, and reliable frontend and backend systems with minimal dependencies on other teams.
• Lead development independently while collaborating closely with Product, Design, and Business stakeholders.
• Make pragmatic architecture and technology decisions balancing speed, quality, and long-term scalability.
• Write and review high-impact code across frontend and backend systems
• Identify and solve ambiguous, complex technical problems with limited requirements or constraints.
• Establish lightweight but effective engineering best practices, coding standards, and processes suitable for a startup environment.
• Drive performance, scalability, reliability, and security improvements as the product and user base grow.
• Own production readiness, monitoring, incident response, and post-mortems for the systems you build.
• Author clear technical documentation, RFCs, and architecture decisions to enable future scaling of the team.
• Mentor engineers as the team grows and help set the technical bar for the organization.
• Evaluate build vs. buy decisions and lead system migrations or refactors when needed.

Requirements

• 10+ years of software engineering experience with strong full-stack expertise
• Proven ability to independently own and deliver large technical initiatives in startup or high-growth environments
• Expert-level proficiency in JavaScript and TypeScript Strong experience with React.js or similar modern frontend frameworks
• Strong backend experience with Node.js and Golang Deep experience with SQL, NoSQL, and in-memory databases, including schema design and performance tuning
• Experience designing and building RESTful APIs, GraphQL APIs, and microservices or modular monolith architectures
• Hands-on experience with cloud platforms (AWS, GCP, or Azure)
• Strong experience with CI/CD pipelines, infrastructure automation, and DevOps practices Proficiency with Docker and Kubernetes (or willingness to own production infrastructure directly)
• Experience with event-driven systems and message queues (Kafka, RabbitMQ, etc.)
• Strong understanding of system design, scalability, and trade-offs in early-stage products
• Excellent problem-solving skills and comfort working with ambiguity and minimal direction
• Clear and effective communication skills, especially when translating business needs into technical execution
• Experience leading system migrations, refactors, or platform evolution in fast-paced environments

What Success Looks Like

• You independently deliver a critical product or platform initiative with high quality and reliability
• Architecture decisions enable rapid iteration today without blocking future scale
• Engineering velocity improves due to clear ownership, strong technical foundations, and reduced ambiguity
• Production issues are rare, well-understood, and resolved quickly The team looks to you as the technical standard and decision-maker