Founding Engineer (Backend)

About Karsa At Karsa, we’re building the global dollar account—enabling millions of people in emerging markets to protect their savings from currency volatility through stablecoins. Over 1B people live in economies with severe inflation, losing hundreds of billions of dollars each year in savings, fees, and time spent navigating broken financial systems and black-market exchanges. In these countries, stablecoins offer a lifeline to financial stability. Karsa allows them to hold dollars and earn steady yield, spend anywhere with a card, and remit money across the world—faster and cheaper than ever before. We’ve already launched with active users across Pakistan, India, Nigeria, Kenya, and Paraguay, rapidly expanding to additional markets. We’re backed by YC and the best investors in our industry, deeply experienced in crypto, and dedicated to providing financial freedom to billions. The Role As a founding engineer at Karsa, you'll be integral to shaping our product from the ground up. You'll own significant portions of our technical stack and drive critical infrastructure decisions, directly impacting users in some of the world's most economically challenging regions. In particular, you’ll focus on building and scaling the backend systems that power our product, from integrating crypto wallets and fintech rails, to managing secure user data and building cloud infrastructure. The role requires adaptability, broad technical range, and a strong focus on security. Who you are: Mission-driven: We’re building tools that can protect a family’s savings in a collapsing economy. This is an incredibly challenging, decade-long sprint, but if we succeed, it changes everything—from individual lives to national systems. This weight should matter to you. Founder mindset: You’re not an IC. You’re our partner. You need to be highly opinionated on our product and market, be ready to work on anything, and drive our direction from day one. Hungry: We work 6–7 days a week, often late into the night, since our users don’t live on a 9-5. The two of us put together a stablecoin bank + cross-border payments + a card in <3 months. We’re not looking for a big team. We need a force multiplier. What You'll Do: Implement and optimize integrations with crypto infrastructure providers (Wallet infrastructure, On/off ramps, payment service providers, stablecoin issuers). Architect secure, performant, and reliable backend services with Next.js and AWS. Design and manage high-throughput databases (Postgres), ensuring data integrity and security. Collaborate closely with the founders to define product strategies, iterate quickly, and ship impactful features. What We're Looking For Strong experience building backend systems using serverless tools (Next.js API routes, AWS Lambda) Deep knowledge of database design, particularly with Postgres (schema optimization, query performance, etc.) Expertise in secure API development, authentication systems, and protecting sensitive financial data Proficiency with cloud infrastructure (AWS tooling like S3, KMS, IAM, Lambda, etc.) and modern DevOps (monitoring, logging, Docker, etc.) Experience integrating with third-party financial services, payment processors, or blockchain infrastructure Great to Have: Experience with fintech, blockchain, or crypto platforms Experience deploying secure financial services handling sensitive user information and transactions. Passion for global economic empowerment and emerging markets. Note: Must be in NYC; or if you’re willing to relocate, we’ll help you do so ASAP.