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

Workday•Pleasanton, CA

2d•$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'll help design and build the high-throughput, low-latency APIs and backend services that power Workday's next generation of products and agents. You'll turn product requirements into scalable services, object models, and API endpoints, applying strong object-oriented design principles to build systems that are easy to maintain and extend over time. You'll also help shape how the team approaches API design, improve performance and observability across critical systems, and support the growth of engineers around you.

Requirements

Minimum of 8 years of experience in software development engineering, architecting, building, and scaling robust and efficient software systems.
Minimum of 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.
Minimum of 5 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.

Nice To Haves

Skilled 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.
In-depth 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.
In-depth 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.
Demonstrated 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.
Skilled technical writer, with experience producing comprehensive technical specifications, design documents, RFCs, API documentation, and integration best-practice guides.
Experience using 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 the design and development of APIs, backend services, and platform features used across Product Engineering.
Turn product requirements into clear service boundaries, domain models, and well-designed API endpoints, using OpenAPI and internal standards.
Help expose product capabilities through REST, GraphQL, SOAP, and emerging integration patterns that work well for agents, internal teams, and external consumers.
Improve performance and scalability through latency optimization, capacity planning, caching, and resiliency patterns for mission-critical flows.
Build observability into product APIs — metrics, tracing, logging, and dashboards — and use that data to guide technical decisions.
Support design reviews, code reviews, and technical documentation, and mentor junior and mid-level engineers.
Participate in on-call and incident response, including root cause analysis and long-term fixes for significant issues.