Staff Fullstack Engineer

About the Role

We are seeking a Staff Full Stack Engineer to lead the technical direction of the team that builds Alpaca's Trading API product. Trading API serves developers, traders, and institutions who trade directly with Alpaca. The team owns that customer experience end to end: how customers access the platform, how their accounts are structured and secured, and the applications they use to trade.

The work spans the stack: customer-facing trading applications, the identity, account, and permission systems behind them, and integrations for partner apps and AI agents. The team also builds customer-facing trading features end to end, across our API.

This is a high-trust domain. These systems decide who can act on an account and what they are allowed to do. A defect can expose customer data, let the wrong person place a trade or move money, or lock a customer out at the moment they need to trade. The customer-facing surfaces also carry real-time trading: an order ticket or positions view that shows stale or wrong data can lead to a bad trade. We are looking for an engineer who has built and owned systems like this — identity and authorization, account models, and trading or financial applications — and who is as comfortable designing an authorization model as shipping the interface built on top of it.

You will not manage people directly. You will lead through architecture, code, design reviews, and mentorship, and you will remain a principal contributor. You will be the senior technical anchor for the team, partnering with the engineering manager, Product, and Design, and working closely with the trading, margin and risk, and platform teams behind the API.

Key Responsibilities

• Own the architecture and technical roadmap for how customers access and use Trading API: identity and authentication, authorization and permissions, account and sub-account models, partner OAuth, and customer-facing trading and account-management applications.
• Design the access model for increasingly complex account structures — multiple users per account, sub-accounts, entity and advisor accounts, and delegated API and agent access — so that permissions are explicit, auditable, and enforced on the server.
• Lead technical delivery of next-generation Trading API customer applications, including real-time market data, order entry, and positions and order views, as the product expands to new customer surfaces.
• Drive the move from legacy monolith endpoints to a dedicated application backend, with clear API contracts between customer applications and platform services such as trading, accounts, transfers, ledger, and market data.
• Set the security bar for customer-facing systems: session and credential handling, MFA and passkeys, OAuth flows, rate limiting, input validation, and fast, durable responses to security findings.
• Set the standard for safe delivery: feature flags, staged rollouts, preview environments, testing strategy, and production observability.
• Partner with Product, Design, Compliance, Security, Brokerage Operations, and adjacent engineering teams to define behaviour and integration boundaries.
• Lead design reviews, mentor senior and mid-level engineers, and raise the engineering bar as the team grows.
• Act as a technical point of escalation for production issues on customer-facing Trading API systems, and drive durable prevention after incidents.

Qualifications

• 8+ years of software engineering experience, with significant time on both backend services and customer-facing applications. Evidence of scope and ownership matters more than a strict year count.
• Proven ownership of a production system where a defect could expose customer data, grant the wrong access, or cause financial loss.
• Deep experience with authentication and authorization: OAuth 2.0 and OpenID Connect, session and token management, MFA, and role- or attribute-based permission models.
• Strong backend expertise in Go, or deep experience in Java, Kotlin, C#, or Rust and a clear willingness to work primarily in Go.
• Strong frontend experience with TypeScript and React, including complex, state-heavy applications. Experience with real-time data over WebSockets or other streaming protocols is strongly preferred.
• Solid knowledge of relational databases (PostgreSQL preferred), API design (REST and gRPC), and service-oriented systems running on Kubernetes.
• Demonstrated care for correctness and security: threat modelling, testing strategy, edge-case analysis, and safe production rollout.
• Clear communication with engineers, designers, product managers, and compliance and security partners, including when requirements are ambiguous or still being defined.
• Track record of technical leadership and mentorship across teams. Product-minded: you care what the customer sees and why, and you are effective as a teammate.

Preferred Skills

• Experience building trading, brokerage, or other financial applications: order entry, positions and P&L, charting, or real-time market data.
• Experience with identity platforms or building identity in-house (for example, Amazon Cognito, Keycloak, or Auth0), passkeys and WebAuthn, or delegated access for third-party applications.
• Experience with API platforms and developer products: API keys, scopes, rate limits, SDKs, or developer dashboards.
• Experience with agentic AI integrations, such as MCP servers or tooling that lets AI agents act safely on a user's behalf.
• Familiarity with FIX or institutional trading workflows.
• Experience leading migrations off a legacy monolith in production-critical environments.