Sr Software Engineer – API Platform, Product Engineering (Python/Typescript)

Workday•Pleasanton, CA

4d•$148,200 - $264,000•Hybrid

About The Position

The Product Engineering organization builds the product experiences that customers use every day. Our teams design and deliver features that sit on top of Workday’s core platforms and services, and increasingly depend on powerful, well-designed APIs to support agentic experiences and AI-driven scenarios. This team focuses on evolving the API surface and supporting mission-critical product flows used by Product Engineering for agentic AI use cases. We partner closely with internal Workday teams to design APIs and patterns that are consistent, reliable, scalable, and easy to consume. You will help shape the API foundation, architecture, and operating model that makes it easy for Product Engineering to build agent-ready, high-quality APIs. This includes working on product capabilities end to end, from product and domain modeling through backend implementation, API endpoint design, testing, and production operations. If you enjoy building products, services, and APIs that other engineers, customers, and AI agents love to use, you’ll feel at home on this team. As a Senior Software Development Engineer in Product Engineering, you will be a technical leader in designing and delivering high-throughput, low-latency APIs, backend services, and frameworks that support Workday’s next generation of products and agents. You will help translate product requirements and user workflows into scalable services, object models, data models, and API endpoints. You will bring hands-on experience in designing and building products end to end, and you will apply strong object-oriented modeling and software design principles to create maintainable, extensible, and production-ready systems. You will shape API design, drive performance and observability improvements, and coach and grow future senior engineers across the team.

Requirements

8+ years of experience in software development engineering, architecting, building, and scaling robust and efficient software systems.
5+ years of experience in software engineering, with hands-on experience in object-oriented modeling and software design concepts such as domain modeling, abstraction, encapsulation, extensibility, and maintainable service design
4+ years of experience designing API endpoints that expose product functionality clearly, consistently, securely, and at scale.
Bachelor’s degree in Computer Science, Engineering, or related discipline, or equivalent practical experience.
Strong ability in algorithmic thinking, including advanced data structures and algorithms such as graphs, concurrent data structures, and caching/eviction strategies, to design and optimize solutions for complex API orchestration, request routing, and high-throughput workloads.
Solid experience with API development, including REST, SOAP, GraphQL, OpenAPI/Swagger-driven design, and designing and building scalable, secure APIs and API integration patterns.
Experience creating API endpoints that map clearly to product functionality, domain concepts, and customer-facing workflows.
Hands-on experience building and operating large-scale systems with complex product domains, high transaction volumes, and enterprise-grade reliability requirements.
Strong understanding of code testing methodologies, such as contract testing, performance testing, system testing, and integration testing, and experience with advanced testing tools or frameworks such as JUnit, ScalaTest, Postman, Mockito, Jacoco, or Scoverage.
Strong understanding of object-oriented design principles, including SOLID, abstraction, encapsulation, inheritance, composition, and polymorphism.
Practical experience applying domain-driven design concepts, object-oriented modeling, and common architectural patterns, such as layered architecture and hexagonal architecture, to scalable software systems.
Solid understanding of software development principles and advanced development methodologies such as continuous delivery, trunk-based development, and test-driven or behavior-driven development.
Solid experience with source control management tools such as Git and advanced branching and merging strategies across multiple teams or services.
Proven ability to lead team collaboration within a software development team and mentor junior and mid-level engineers through design reviews, technical guidance, code reviews, and knowledge sharing.
Strong skills in technical writing, including comprehensive technical specifications, design documents, RFCs, API documentation, and integration best-practice guides.

Nice To Haves

Experience leveraging AI-assisted code generation and review tools, such as Cursor, Claude Code, or GitHub Copilot, to improve development speed and quality.
Exposure to MCP or similar agent/tool integration models is a strong plus.

Responsibilities

Lead design and implementation of APIs, backend services, and platform features used by Product Engineering teams.
Champion consistent API standards, object modeling practices, design patterns, and tooling that align with cross-org guidance while solving concrete product needs.
Help Product Engineering teams expose product capabilities via REST, GraphQL, SOAP, and emerging integration patterns in a way that is friendly to agents, internal teams, and external consumers.
Translate end-to-end product functionality into clear service boundaries, domain models, and well-designed API endpoints.
Contribute to large-scale systems that require high availability, performance, extensibility, observability, and operational excellence.
Lead end-to-end design and development of complex backend services, product capabilities, and APIs.
Design and build product functionality end to end, including domain modeling, object modeling, service design, API contract definition, implementation, testing, deployment, and production support.
Drive consensus with product managers, architects, and partner teams to define clear, evolvable API contracts, object models, and data models using OpenAPI and internal standards.
Create API endpoints that expose product functionality clearly, consistently, securely, and at scale.
Apply object-oriented modeling concepts and domain-driven design principles to create scalable, maintainable, and extensible software architectures.
Drive performance and scalability improvements, including latency optimization, capacity planning, caching strategies, and resiliency patterns for mission-critical product flows.
Design and implement observability for product APIs, including metrics, tracing, structured logging, and dashboards, and use data to drive technical decisions and SLOs.
Collaborate on frameworks, tools, and patterns that make it simpler for other Product Engineering teams to define, publish, consume, and maintain APIs.
Work with data platform teams to define patterns for exposing data safely and efficiently to API and agent workflows.
Provide technical leadership through design reviews, RFCs, spike investigations, code reviews, and coaching junior and mid-level engineers.
Participate in and improve on-call and incident response processes; own root cause analysis and long-term remediation for significant issues.
Act as a trusted technical partner to teams across Product Engineering, helping them make product design, API design, integration, and architecture decisions.