Staff Engineer, API Core Platform

Staff Engineer — API Core Platform About the role Together AI is seeking an experienced Backend Engineer to found Together’s API Platform team within the Production Foundations organization. In this role, you will define, build, and scale the core systems and architecture that power Together’s mission-critical APIs — including public customer APIs used directly by customers and via SDKs, CLIs, as well as the client APIs powering Together’s Cloud UI. In the near term, you will improve and standardize the backend API layer within our primary Next.js monolith, raising the bar on reliability, performance, and consistency. In parallel, you will design and lead the evolution toward scalable, purpose-built next-gen API platform solutions optimized for different Public API and Client API use cases and traffic patterns — defining the long-term architecture and driving its incremental rollout. This is a deeply hands-on role for an engineer who thrives on writing critical-path code and building platforms that unify engineering efforts across teams. You will work across backend systems, infrastructure layers, identity and access flows, and developer tooling to establish a cohesive API strategy that supports Together’s rapidly growing AI Cloud. Responsibilities Design and drive the evolution of Together’s API platform, defining how APIs are built, versioned, secured, tested, and operated across the company Own and improve the backend API layer within our primary Next.js monolith, raising the bar on consistency, reliability, and performance Architect and lead the transition toward scalable, purpose-built API platforms optimized for different traffic patterns and product surfaces Write and maintain critical-path platform code that multiple services and product teams depend on Design and implement robust authentication, authorization, and identity-aware access patterns across public and internal APIs Establish performance standards for high-throughput APIs, implementing caching, rate limiting, fan-out control, and graceful degradation strategies Raise the bar on API observability and reliability, defining SLOs, monitoring, alerting, and incident response practices Drive API data modeling and schema generation strategies to ensure long-term maintainability and developer ergonomics Partner with infrastructure and security teams to maintain a strong security posture and evolve toward zero-trust architectures Mentor engineers, influence architectural direction across teams, and help define hiring standards as the API Platform grows Required Qualifications 8+ years of experience building and operating large-scale, distributed backend systems in production environments Proven experience building or significantly evolving an API platform used by multiple teams or customer-facing products Expert-level proficiency in one or more of Golang, TypeScript, C++, or Java Deep expertise in API performance and scalability, including caching strategies, rate limiting, parallelization, fan-out control, and graceful degradation Strong experience designing and implementing production-grade authentication and authorization systems for customer-facing APIs Demonstrated ability to drive cross-team architectural initiatives without formal authority, aligning multiple stakeholders around long-term platform direction Experience building and operating systems using Infrastructure as Code (Terraform, AWS CDK, Pulumi) and modern CI/CD workflows Bachelor’s or Master’s degree in Computer Science, Computer Engineering, or equivalent practical experience Nice to Have Experience with GraphQL or schema-based API federation systems Experience evolving APIs from monoliths to modular, platform-oriented architectures Experience designing and operating API schema generation and validation systems Experience building developer-facing SDKs or command-line tools Experience designing and operating multi-region, globally distributed API systems Experience designing horizontally scalable API systems capable of handling high request volume and burst traffic patterns Experience running production workloads in Kubernetes-based environments Experience building services in zero-trust or identity-aware architectures Experience with AWS networking, traffic management, and load balancing Experience with Cloudflare or CDN-level API performance optimization   About Together AI Together AI is a research-driven artificial intelligence company. We believe open and transparent AI systems will drive innovation and create the best outcomes for society, and together we are on a mission to significantly lower the cost of modern AI systems by co-designing software, hardware, algorithms, and models. We have contributed to leading open-source research, models, and datasets to advance the frontier of AI, and our team has been behind technological advancement such as FlashAttention, Hyena, FlexGen, and RedPajama. We