Senior Fullstack Engineer- Auth Team

Alpaca; Greater London; Remote; GBP 110,000 - 150,000; Full time

Benefits offered by this job

Health benefits

Stock options

New Hire Home-Office Setup: USD $500

Monthly Stipend: USD $150 per month

Job summary

Alpaca is seeking a Senior Full Stack Engineer to build and operate its authentication, authorization, and IdP systems. You will work primarily in Go with backend services, gRPC/REST APIs, and React/TypeScript for auth UI, with some Java for IdP extensions. Helm, logs, and deployments are part of the role.

You will own end-to-end work from requirements to delivery, collaborate across teams, and help modernize authentication patterns as the platform scales.

Qualifications

• 5+ years writing code in strongly-typed languages, with at least 1 year in Go.
• Experience building web apps with React and TypeScript.
• Experience with relational databases (PostgreSQL preferred).
• Startup experience and ability to thrive in ambiguities.
• 3+ years working on systems at scale.
• Ability to own work end to end from requirements to deployment.

Responsibilities

• Build and improve authentication-related experiences in customer and partner apps.
• Develop and maintain authentication, authorization, and IdP services.
• Create and evolve shared libraries and SDKs.
• Integrate with identity providers and manage login policies.
• Deploy, monitor, and troubleshoot identity services in production.
• Modernize legacy authentication patterns.
• Own work end to end from requirements through delivery.
• Collaborate with other teams on identity integration.
• Maintain high code quality, write tests, and participate in code reviews.
• Investigate incidents and participate in on-call rotation.

Skills

Go

React

TypeScript

PostgreSQL

Ownership

End-to-end ownership

Systems at scale

Startup experience

Tools

Kubernetes

Helm

OpenAPI

Kafka

Keycloak

Job description

Who We Are

Alpaca is a US-headquartered, global leader in agent-first brokerage infrastructure for stocks, ETFs, options, crypto, fixed income, 24/5 trading, and more. Amongst our subsidiaries, Alpaca is a licensed financial services company, serving hundreds of financial institutions across 40 countries with our institutional-grade APIs. This includes broker-dealers, investment advisors, wealth managers, hedge funds, and crypto exchanges, totalling over 10 million brokerage accounts.

Our global team is a diverse group of experienced engineers, traders, and brokerage professionals who are working to achieve our mission of opening financial services to everyone on the planet. We're deeply committed to open-source contributions and fostering a vibrant community, continuously enhancing our award-winning, developer-friendly API and the robust infrastructure behind it.

Alpaca is proudly backed by $400 million in funding from top-tier global investors including Portage Ventures, Spark Capital, Tribe Capital, Social Leverage, Horizons Ventures, Opera Tech Ventures, SBI Group, Derayah Financial, Unbound, Peak XV, Elefund, and Y Combinator.

We're a dynamic team of 400+ globally distributed members who thrive working from our favorite places around the world, with teammates spanning the USA, Canada, Japan, Hungary, Nigeria, Brazil, the UK, and beyond! We're searching for passionate individuals eager to contribute to Alpaca's rapid growth. If you align with our core values—Stay Curious, Have Empathy, and Be Accountable—and are ready to make a significant impact, we encourage you to apply.

About The Role

As a Senior Full Stack Engineer on the Platform Team, you will develop and operate Alpaca’s authentication, authorization, and Identity Provider (IdP) systems - the systems that handle user login, access control, and secure access across our APIs, customer products, and internal tools. We are looking for experienced engineers who are comfortable owning services end to end: API design, data modeling, deployments, and production debugging. Most of your time will be spent writing Go (backend services, gRPC/REST APIs, shared client libraries), with meaningful work in React/TypeScript for auth-related UI, and occasionally Java for identity-provider extensions. You will also work with Helm charts, analyze logs and metrics, manage deployments, and help other teams to integrate with our services.

Things You Get To Do

• Build and improve authentication-related experiences in customer and partner web applications, including login, permissions, and credential management.
• Develop and maintain the platform’s authentication, authorization, and IdP services.
• Create and evolve shared libraries and SDKs.
• Integrate with identity providers and keep login and access policies working reliably across products.
• Deploy, monitor, and troubleshoot identity services in production.
• Help modernize legacy authentication patterns as the platform evolves.
• Own work end to end, from requirements through delivery and follow-up.
• Collaborate with other engineering teams on identity and access integration.
• Maintain high code quality, write tests, and participate in code reviews.
• Help investigate incidents and bugs, including on-call rotation.

Who You Are (must-haves)

• You have 5+ years of experience writing code in strongly-typed languages, with at least one year of experience in Go.
• You have experience building web applications with React and TypeScript.
• You have worked with relational databases before - we use PostgreSQL, but we are not particularly picky about this one as long as you have a solid grasp on the fundamentals.
• You have worked at a startup before - you thrive in ambiguous environments, embrace changing priorities, know when to balance technical debt with speed, and proactively tackle whatever needs to get done without relying on pre-existing processes or documentation.
• You are not afraid of taking a task from start to finish - gathering requirements, figuring out and implementing the best technical solution, then deploying and monitoring the results.
• You have worked at least 3 years on systems at scale.

Who You Might Be (nice-to-haves)

• You know what a JWT token is, and how OpenID Connect and SAML work. Maybe you even heard about Keycloak, or have worked on authentication systems before.
• You have experience with role-based access control.
• You have built or maintained OpenAPI-driven HTTP APIs.
• You are familiar with Kubernetes and Helm.
• You have experience with Java.
• You understand how Kafka works - maybe you even worked with Redpanda before.
• You have experience with Grafana’s observability stack - Prometheus, Tempo and all the rest. You might have even written a PromQL query for a new alert once or twice.

How We Take Care of You

• Competitive Salary & Stock Options
• Health Benefits
• New Hire Home-Office Setup: One-time USD $500
• Monthly Stipend: USD $150 per month via a Brex Card

Alpaca is proud to be an equal opportunity workplace dedicated to pursuing and hiring a diverse workforce.

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