About the Role

We have multiple openings for Senior Software Engineers to join our core development team. As a Senior Software Engineer at our fintech startup, you will design and build critical components of our account-to-account payments platform. You’ll be working on a modern tech stack to develop features that might include everything from customer onboarding and bank account connectivity, to payment transaction processing, fraud detection integrations, and user-facing dashboards. This is a hands-on engineering role where you’ll have broad ownership: one day you might implement a new API endpoint or microservice, and the next day debug a complex issue across the stack or refine our CI/CD deployment pipeline.

In this early-stage environment, engineers aren’t siloed—expect to work across the stack and touch various aspects of the system. Some of our engineers focus more on backend (building out our secure RESTful APIs, database schemas, and external integrations), while others drive frontend efforts (creating intuitive web interfaces for our clients and perhaps refining our embeddable bank connection widget). We value versatility: a willingness to learn new technologies and pitch in where needed. You’ll collaborate closely with product managers to understand requirements, and with designers to ensure the UI is polished and user-friendly. Security, reliability, and performance are paramount in fintech, so you will incorporate best practices for handling sensitive financial data and ensuring high uptime.

As a senior member of the team, you will also help set coding standards, mentor less-experienced developers, and influence architecture decisions. We operate in a fast-paced, agile fashion: shipping iteratively, gathering feedback, and continually improving. This role is full-time in Denver, CO with hybrid/remote flexibility. We offer a competitive base salary, benefits, and equity participation. If you’re excited by the idea of building complex systems in a startup setting and seeing the direct impact of your code in the product, we’d love to hear from you.

Key Responsibilities

• Design & Develop Features – Implement new features and services for our platform end-to-end. This could range from back-end logic (e.g., creating a service for handling ACH payment requests with proper verification) to front-end interfaces (e.g., building a section of the customer dashboard for viewing transaction history).

• Build Scalable APIs – Create and maintain RESTful APIs that are secure, well-documented, and easy for clients to integrate. Ensure our API endpoints (customer creation, payments, identity verification, etc.) are efficient and handle errors gracefully.

• Integrate External Services – Work with third-party integrations critical to our fintech product. For example, integrate open-banking APIs (Plaid, Finicity, MX) for pulling bank account data, or identity verification services for KYC. Handle webhooks and callbacks from these services reliably.

• Database & Systems Management – Design relational database schemas to store customers, accounts, transactions, and more. Write efficient queries and optimize where necessary. Contribute to decisions on data storage solutions for new features (SQL vs NoSQL, caching strategies, etc.).

• Quality Assurance – Write unit, integration, and end-to-end tests to ensure code quality and prevent regressions. Participate in code reviews, providing feedback to peers and maintaining a high standard of engineering excellence. Debug and resolve production issues, performing root cause analysis and implementing fixes.

• DevOps & Deployment – Contribute to our build and deployment process. Create CI/CD pipelines or scripts to automate testing and deployment. Containerize services (using Docker, etc.) and possibly work with infrastructure-as-code tools to manage our cloud resources. Ensure our applications are monitored and logging appropriately for quick issue identification.

• Security & Compliance – Implement security best practices at every layer. This includes proper authentication/authorization in APIs, encryption of sensitive data, protection against common vulnerabilities (SQL injection, XSS, CSRF), and adherence to compliance standards (e.g., PCI or SOC2 relevant controls).

• Collaboration & Mentorship – Work closely with cross-functional team members – understand requirements from the Product Lead, iterate on UI with the Design Lead, and coordinate data needs with the Data Science team. As a senior engineer, mentor junior developers through pair programming, code review, and knowledge sharing. Help cultivate an engineering culture of collaboration, innovation, and continuous improvement.

• Architecture & Innovation – Take part in high-level architecture discussions. Help evaluate and choose new technologies or frameworks as we evolve the platform. Identify areas of refactoring or tech debt and proactively improve the codebase for the long term. Innovate by prototyping new ideas that could enhance our product’s performance or capabilities.

Required Qualifications

• Strong Coding Skills – 5+ years of professional software development experience, with a primary focus on .NET and TypeScript. Proficient in building robust backend services and modern web applications using C#, TypeScript, and occasionally Python. Comfortable applying architectural and design patterns such as CQRS, IoC, Clean Architecture, DDD, and SOLID principles. Skilled in using tools like Entity Framework and AutoMapper, and able to quickly learn new technologies as needed.

• Web Application Development – Significant experience building modern web applications and services using .NET and TypeScript. Strong full-stack capabilities, with a focus on backend development including REST APIs and microservices built using .NET. Frontend experience includes building responsive, user-friendly interfaces with TypeScript and modern JavaScript frameworks. Emphasis on maintainable architecture, domain-driven design, and clean separation of concerns across the stack.

• Database Knowledge – Strong understanding of SQL and relational databases (designing schemas, writing queries, optimizing performance). Experience with one of the popular DBMS (PostgreSQL, MySQL, etc.). Familiarity with ORM frameworks and caching mechanisms. Exposure to NoSQL databases is a plus.

• Distributed Systems & API Integration – Experience integrating external APIs and services. Familiarity with message queues or asynchronous processing patterns to handle workflows (for example, processing background tasks like sending emails or handling webhook events from partners).

• Problem Solving – Excellent debugging and problem-solving abilities across the stack. Ability to break down complex problems, determine root causes, and come up with practical solutions. Experience with performance tuning and scaling applications (identifying bottlenecks, optimizing code or queries, etc.).

• Best Practices & Testing – Deep understanding of software engineering best practices: version control (Git), code reviews, testing methodologies, and agile development. Proven ability to write clean, maintainable code and advocate for coding standards.

• Security Mindset – Knowledge of common security pitfalls and how to avoid them. Experience implementing secure coding practices (input validation, encryption, secure credential storage, etc.). Awareness of data privacy considerations and compliance in a fintech context.

• Communication & Teamwork – Strong communication skills and the ability to work in a team. Experience working in an agile environment and collaborating with product managers, QA, and other engineers. Comfortable providing and receiving constructive feedback.

• BS/MS in Computer Science or equivalent experience – solid computer science fundamentals (data structures, algorithms, complexity) evidenced by education or work experience.

Preferred Qualifications

• Fintech or Payments Experience – Prior work on financial systems, payment processing, or banking software. Familiarity with concepts like transaction ledgers, reconciliation, payment gateways, ACH file processing, or regulatory compliance in software (PCI DSS, etc.).

• Open Banking & Financial APIs – Experience using APIs from Plaid, Stripe, PayPal, or similar in a project. Understanding of how to handle bank authentication flows, tokens, and secure data transfer between our system and financial institutions.

• Cloud Infrastructure – Hands-on experience with cloud platforms (AWS, GCP, or Azure). Knowledge of services like AWS EC2/ECS/EKS, Lambda, RDS, S3, etc., and how to architect applications for scalability and reliability in the cloud.

• DevOps Culture – Familiarity with infrastructure as code (Terraform, CloudFormation), and configuration management. Experience with monitoring and observability tools (Datadog, Prometheus, etc.) to ensure system health.

• Performance Optimization – Experience with performance testing and tools (load testing APIs, profiling applications). Ability to optimize code, queries, and front-end performance (reducing load times, optimizing bundles) for a better user experience.

• Contributions & Leadership – Demonstrated ability to lead projects or initiatives. If you have acted as a tech lead, or have mentoring experience, it’s a plus. Contributions to open source projects or a portfolio of personal projects showcasing your skills can also bolster your application.