Sr. Software Engineer – API & Auth Platform

Betterment•New York, NY

7h•$170,000 - $195,000•Hybrid

About The Position

The API & Auth Platform team enables product teams across Betterment to build and operate APIs quickly, enjoyably, and securely. As Sr Software Engineer, you will work with a team of senior/staff engineers stewarding our shared GraphQL API frameworks, authentication and access control systems, and internal tooling platform. You will help build core pieces of the GraphQL API frameworks powering our customer-facing web and mobile applications, working closely with engineering leadership. You will also collaborate with operations, customer support, and compliance partners to ensure our internal APIs let teams operate Betterment systems with the rigor our customers and regulators expect. As AI tooling reshapes how we build and operate our systems, you will have significant influence over how Betterment's APIs support AI agents and tooling safely in a regulated financial services environment. This role is based out of our NYC office.

Requirements

A contributor capable of working in sensitive auth systems, working alongside senior and staff IC colleagues to shaping their technical direction.
Experience building on or contributing to a shared API platform — ideally GraphQL — with an appreciation for the frameworks, conventions, and developer tooling that let product teams introduce new capabilities, support existing usage, and gracefully retire legacy functionality.
Experience with modern authentication/authorization patterns (OAuth 2.0, OIDC, passkeys), with an appreciation for the importance of adoption, long-term support, and security testing.
Experience operating systems in production that other engineering teams depend on, with an eye for observability, testing, and safe rollout.
Comfort with the evolving AI landscape — using AI tooling in your own workflow and thinking clearly about how AI agents should access APIs safely.
Fullstack development experience including GraphQL and one or more server-side languages (Ruby, Java, TypeScript, C#, Python, etc.)
Experience collaborating across discipline and team boundaries.
An open-minded approach when navigating the tension between moving fast, customer quality, and regulatory requirements.

Responsibilities

Work with a team of senior/staff engineers building the API, authentication, and internal tooling foundation that every Betterment team relies on.
Help deliver the GraphQL API frameworks powering our customer-facing and internal apps, including agentic tooling for AI-native API development workflows.
Contribute to Betterment's authentication and authorization systems, keeping them current with industry best practices.
Build platform capabilities like secure, first-party MCP access to Betterment APIs — and the reliability, security, and developer experience work that makes them trustworthy.
Embed with the product teams who build on your platform every day.
Develop broad Betterment domain expertise in the process.
Help make the standards that keep shared systems healthy visible and easy to meet, and help teams understand the "why" behind them.
Participate in efficient, blameless incident response across your team and the teams building on the API platform.
Invest in observability that serves both developers and internal tool users.
Mentor junior engineers, sharing your experience to expand their impact and accelerate their growth.