Founding Engineer - APIs, SDKs & Developer Experience

ABOUT EXA Exa is building the infrastructure layer for institutional tokenized finance. We allow fintechs, neobanks and financial institutions to integrate tokenized funds and onchain yield products through one standardized framework. Financial institutions integrate Exa once and access an expanding product catalogue without building direct integrations one by one that introduce segregated onboarding, data, settlement, reporting and reconciliation workflows - all expensive to maintain across multiple issuers, protocols, custodians, jurisdictions and reporting formats. We bring more than a decade of experience across digital assets and institutional capital allocation having processed more than $1 billion in transaction volume, helped direct more than $60 million into onchain products and managed nine figures portfolios. We are now turning that experience into scalable financial infrastructure. THE ROLE We are looking for a Founding Engineer to take ownership of Exa’s core APIs, SDKs, integrations and developer experience. You will work directly with the founders to build the orchestration layer connecting financial institutions with custodians, compliance providers, asset managers and onchain infrastructure. → design and build production-grade APIs and SDKs → integrate custodians, tokenized funds, vaults, compliance providers and data infrastructure → translate legal, regulatory and product requirements into eligibility rules, permissions and operational workflows → build authentication, access controls, audit trails, webhooks and event-driven systems → develop reporting, monitoring, reconciliation and compliance-support tooling → create sandbox environments, technical documentation and example applications → work directly with partners across engineering, compliance, legal and operations → shape our architecture, engineering standards and technical culture This is a high-ownership role. You will help define what we build, make architectural decisions and take systems from initial design into production. WHAT WE ARE LOOKING FOR You are likely a senior backend engineer, technical lead or early-stage startup engineer with experience building infrastructure used by external developers. Strong experience with APIs, backend systems and developer tools is essential. Experience with TypeScript, Node.js, Python, Go or Rust is useful, alongside cloud infrastructure, CI/CD, testing, monitoring and production reliability. Experience in fintech, payments, custody, blockchain infrastructure, smart contracts, onchain data or financial reporting is a strong advantage. We care less about whether you match every technology on a checklist and more about whether you can understand complex systems, simplify them and deliver reliable software. HOW WE WORK We are a small, senior and highly accountable team. Our culture is direct, practical and low-ego. We move quickly, communicate openly and avoid unnecessary layers of management. People at Exa are expected to challenge decisions, identify problems early and take ownership of outcomes. As one of our first technical hires, you will have meaningful influence over the product, architecture, future engineering team and direction of the company. COMPENSATION The role includes a competitive salary and meaningful early-stage equity. This is a genuine founding-engineer position. The equity package will reflect the responsibility, commitment and long-term impact expected from the role. To apply, please share with us a short introduction covering what you have built, the systems you have personally owned and why Exa interests you. GitHub profiles, previous products and technical writing are welcome.