Senior Software Engineer; API

• Anthropic is seeking an exceptional Senior Staff Software Engineer to join the Claude Developer Platform team and serve as the senior-most individual contributor across API Engineering. Since launch, the Claude API has seen rapid growth and adoption by companies of all sizes to build AI applications with our industry-leading models
• The API serves as the primary channel for safely and broadly distributing AI's benefits across all sectors of the economy
• This role sets the technical direction for the systems that make Claude accessible to developers, enterprises, and partners at scale
• You will operate at the intersection of technical strategy and execution, partnering closely with Research, Inference, Platform, Infrastructure, and Safeguards to ensure the Claude API is reliable, capable, and positioned to grow with Anthropic's ambitions
• This is a high-agency role that spans all API Engineering teams: API Core owns the foundational reliability and performance of the Claude API; API Capabilities ships frontier model capabilities - vision, tool use, computer use - directly to developers; API Knowledge builds retrieval and grounding systems that let Claude reason over external data; API Distributability ensures Claude reaches customers wherever they need it, with the enterprise-ready infrastructure to support it;
  
  and API Agents builds the infrastructure for long-horizon agentic workflows in production
• Define and drive multi-year technical strategy for the Claude API, setting direction across API Core, Capabilities, Knowledge, Distributability, and Agents
• Identify and personally lead the highest-complexity, highest-impact engineering initiatives spanning multiple teams
• Serve as the primary technical decision-maker for major architectural decisions with org-wide scope
• Partner with Research to evaluate and integrate frontier capabilities; work with Inference and Platform for reliable delivery at scale; collaborate with Infrastructure and Safeguards for reliability, security, and responsible deployment
• Mentor and develop Staff-level engineers across the org
• Drive alignment across Product, GTM, Safety, and beyond while proactively identifying and addressing systemic technical risks
• Technical Stack:
• Languages:
  
  Python, Type Script
• Frameworks:
  FastAPI, React
• Infrastructure: GCP, Kubernetes, Cloud Run, AWS, Azure
• Databases:
  PostgreSQL (AlloyDB), Vector Stores, Firestore
• Tools:
  Feature Flagging, Prometheus, Grafana, Datadog

• Comprehensive health, dental, and vision insurance for you and your dependents
• Inclusive fertility benefits via Carrot Fertility
• 22 weeks of paid parental leave
• Flexible paid time off and absence policies
• Mental health support for you and your dependents
• Competitive salary and equity packages
• Optional equity donation matching at a 1:1 ratio, up to 25% of your equity grant
• Retirement plans with competitive matching
• Life and income protection plans
• $500/month flexible wellness and time saver stipend
• Commuter benefits
• Annual education stipend
• Home office stipends
• Relocation support for those moving for Anthropic
• Daily meals and snacks in the office

Have deep expertise in distributed systems and API architecture, and are effective writing design docs, making architectural calls, and coding in critical paths

Have 12+ years of engineering experience with a clear track record operating at Staff or Senior Staff level

Have demonstrably shaped technical strategy for large-scale API or distributed systems platforms

Drive the highest-leverage technical outcomes without formal authority—you lead through influence, quality of thinking, and trust

Bring strong product instincts and a craftsperson’s approach to API design; you communicate clearly with both technical and non-technical audiences

Are highly effective across org boundaries—you build trust with Research, Inference, Infrastructure, Safeguards, and business stakeholders alike

Location-based hybrid policy:
Currently, we expect all staff to be in one of our offices at least 25% of the time. However, some roles may require more time in our offices

Education requirements:

We require at least a Bachelor's degree in a related field or equivalent experience