Senior Full-Stack Software Engineer

Senior Full-Stack Software Engineer Location: Austin, TX (hybrid, three days a week in office) Employment type: Full-time | Company: Black Unicorn US, Inc. About Black Unicorn Black Unicorn is a technology-driven family office headquartered in the Cayman Islands, with its engineering hub in Austin. We pair private capital with in-house product and engineering teams to launch platforms in payments, financial infrastructure, e-commerce, and media. We invest and operate across several countries and industries, and we move with conviction to create enduring, high-growth companies. The role We're looking for a Senior Full-Stack Software Engineer to build secure, high-scale financial products end to end, from backend services to the web and mobile apps customers use daily. You'll be one of the founding engineers on our Austin team, helping choose the architecture and set the engineering standards. You’ll draw on experience across multiple domains with deep roots in payments and financial systems. We want someone who ships faster using AI-assisted development and is rigorous about reviewing their output. This role is based in Austin, TX, and requires three days a week in our downtown office. What you'll do Design, build, and maintain Java microservices for payment processing, ACH flows, and banking integrations. Build technical systems for the general ledger, reconciliation, and financial reporting. Implement KYC/AML onboarding and identity-verification workflows that meet compliance and audit requirements. Build secure, responsive web applications in React and TypeScript. Develop and ship mobile apps for iOS and Android, and own their releases. Deploy and run services on Azure with strong reliability, security, and observability. Integrate with the enterprise data lake by publishing to it and consuming from it. Use AI coding tools such as Claude for development, code review, testing, and documentation, and help set the team's best practices. Work closely with QA, product, and our delivery partners on release quality. What you bring 10+ years of software engineering experience, including at least 5 years in fintech or banking. Hands-on work with payment systems, banking, ACH, general ledger, and KYC. Strong Java and Spring Boot experience building microservices. Hands-on Azure cloud experience, such as AKS, App Service, Azure SQL, or Service Bus. Solid database skills (relational design, query optimization, and data integrity). Experience with data lake architectures, such as Azure Data Lake or Synapse. Strong front-end experience with React and TypeScript. Experience shipping iOS and Android apps, either native or cross-platform (for example, React Native). Working knowledge of financial compliance, security, and audit requirements. Practical experience using AI tools such as Claude to accelerate coding, testing, and problem-solving, along with good judgment in reviewing AI-generated code. Nice to have Experience with Event-driven architecture (Kafka and Azure Service Bus). Experience with CI/CD, infrastructure as code, and containerization. Experience in PCI DSS, NACHA, or SOC 2 environments. Compensation and benefits We offer a competitive salary and benefits, including comprehensive healthcare coverage and 401(k) matching.