Principal Platform Engineer, Core Platform

Why Charlie Health? Millions of people across the country are navigating mental health conditions, substance use disorders, and eating disorders, but too often, they’re met with barriers to care. From limited local options and long wait times to treatment that lacks personalization, behavioral healthcare can leave people feeling unseen and unsupported. Charlie Health exists to change that. Our mission is to connect the world to life-saving behavioral health treatment. We deliver personalized, virtual care rooted in connection—between clients and clinicians, care teams, loved ones, and the communities that support them. By focusing on people with complex needs, we’re expanding access to meaningful care and driving better outcomes from the comfort of home. As a rapidly growing organization, we're reaching more communities every day and building a team that’s redefining what behavioral health treatment can look like. If you're ready to use your skills to drive lasting change and help more people access the care they deserve, we’d love to meet you. About the Role Core Platform is a platform team. Our customers are Charlie Health's other engineering teams, and our job is to make them faster, safer, and more consistent. We don't ship product features. We build the patterns, services, and guardrails that other engineering teams depend on. As the Principal Platform Engineer on Core Platform, you will be the technical lead for the team building the platform underneath everything Charlie Health ships next: a federated GraphQL front door that fronts every client surface, the event substrate that carries every signal, the identity layer that authenticates every human and every AI agent, and the real-time world model state layer that gives our services and agents a live picture of care. You will be foundational in a replatforming effort, and the primitives you design become the platform's paved roads. This is a technical leadership role without direct reports. You own the team's technical direction, roadmap, and delivery. You will set direction for a team of Staff and Senior Platform Engineers, make the hardest design calls of the replatforming, and stay hands-on in the work. We build with AI as the default. Specs are the primary artifact, agents draft most of the implementation, and the quality gates this team owns are what make that safe in a HIPAA-regulated clinical business. Responsibilities Own the team's roadmap and intake. Balance incoming platform requests and near-term developer pain against long-term architectural investment, with support from the Director of Platform Engineering and the CTO Set the technical direction for the Core Platform team and break the north star architecture into projects the team ships quarter by quarter Run the team's delivery: planning, refinement, and the sprint cadence, with epics scoped to clear milestones and target dates Architect the federated GraphQL supergraph and govern its schema, including subgraph onboarding standards, contract enforcement, and caching and persisted query posture Build authentication and authorization for the platform, including agent identity: scoped, short-lived, audited credentials for non-human principals Design, build, and operate the centralized event substrate, including schema governance, dead-letter conventions, and the producer and consumer patterns that make async the default integration path between services Guide the technical execution of our strangler-fig migration through to cutover, working with product squads as they move onto the new platform Deliver the real-time world model state layer: the stream processing that turns events into state, and the live, low-latency state graph that services and agents query Facilitate the Architecture Advice Guild rituals and provide technical direction on architecture decision records for cross-team decisions and standards Raise the bar for spec writing and agent orchestration on the team, and review specs and agent output with the same rigor you would apply to a senior engineer's work Keep the platform services the team operates reliable: SLOs, monitor-gated deploys, incident leadership, and a seat in the on-call rotation Drive the technical evaluation for procurement and renewals of our critical platform vendors: evaluations, proofs of concept, usage and cost data, and build versus buy recommendations, partnering with the Director who owns the commercial side Mentor Staff and Senior engineers toward larger scope Requirements 10+ years of software engineering experience, including ownership of platform or distributed systems architecture at company scale. You have designed, operated, and evolved systems that other teams build on Hands-on experience with GraphQL federation at scale and with event streaming systems such as Kafka, covering design, schema governance, and production operation rather than just consumption Experience with skills, MCPs, harnesses, agentic tooling ecosystems, or agent orchestration for software development A track record of technical leadership without people authority. You have aligned multiple teams behind architectural outcomes and developed senior engineers Experience owning a team roadmap: intake, prioritization, and delivery planning alongside the architecture work You build with AI agents as part of your daily work. You write specs agents can implement, run agents for real delivery, and know where agent output needs human judgment Proficiency in the stack we run: TypeScript and/or Python services, Postgres, and AWS managed primitives Comfort operating production critical-path systems, including on-call, in a regulated environment Clear, direct communication with engineers, leadership, clinicians, and compliance This role requires 4 days per week in our NYC office. Nice to Haves Real-time stream processing (Flink, Spark, KsqlDB, or similar) and graph databases (Memgraph, Neo4j, Ama