System Integration Engineer

Why we're hiring:

As a Workday Integration Engineer in the WPP Enterprise Data Group, you will design, develop, and maintain REST API-based integrations between Workday and the Work Management Data Spine platform. Workday is the strategic solution for both HCM and Financials across WPP, and this role is critical to ensuring reliable, secure, and performant data flows for employee, financial, absence, and organisational data across the enterprise.

You will leverage deep expertise in the Workday data model and REST APIs to build integration pipelines that extract and synchronise data across both HCM and Financial domains. Your work will ensure that employee profiles, organisational hierarchies, project accounting, client billing, and journal data is delivered accurately to the Data Spine for consumption by WPP Open Work Management Platform.

This role requires expert-level understanding of Workday's REST API surfaces, the underlying HCM and Financial data models, and how business objects relate across modules. You will also support the transition from the interim GPDS (Global People Data Solution) to Workday HCM as agencies are progressively onboarded.

You will be joining a team delivering a critical data integration platform that connects WPP agencies to a centralised Work Management solution, with the opportunity to become the subject matter expert for Workday integrations across the programme.

What you'll be doing:

• Design, build, and maintain integration pipelines using Workday REST APIs (RaaS, WQL, Data Sources) and SOAP Web Services.
• Develop API-based data extraction and synchronisation across both HCM (employee data, absence entitlements, organisational hierarchy, job roles) and Financials (project accounting, client billing, journals, cost centres).
• Implement pagination, rate limiting, error handling, and retry logic to ensure robust and reliable API consumption at scale.
• Build and maintain authentication and authorisation flows using Workday API credentials, OAuth, and certificate-based security.

• Serve as the subject matter expert on the Workday data model across both HCM and Financial modules.
• Map Workday business objects, related objects, and reference data to target data models, understanding how entities relate across modules.
• Advise the engineering team on optimal API endpoints, query strategies, and data extraction patterns for each integration requirement.
• Stay current with Workday data model changes introduced through semi-annual releases and assess their impact on existing integrations.

• Ensure reliable, scheduled synchronisation of HCM and Financial data between Workday and downstream data platforms.
• Support event-driven integration patterns using Workday business process notifications and Azure Event Hubs.
• Manage data format conversions and transformations between Workday API responses (JSON, XML) and downstream platform requirements.
• Define and maintain field mappings, transformation rules, and integration specifications for each data flow.

• Work with data engineering teams to ensure Workday data lands correctly in the platform for downstream processing.
• Contribute to cross-reference identity resolution between Workday identifiers (worker, supplier, cost centre) and canonical records.
• Document integration patterns, API usage guides, and reusable templates for future Workday integration workstreams.
• Collaborate with Workday functional consultants, HR, and Finance teams to align integration outputs with business process requirements.

What you'll need:

• Deep knowledge of the Workday data model across both HCM and Financial modules, including business objects, related objects, and reference data.
• Strong hands-on experience with Workday REST APIs (RaaS, WQL, Data Sources) and SOAP Web Services for data extraction and integration.
• Proficiency in REST API integration patterns including authentication (OAuth, certificates), pagination, rate limiting, and error handling.
• Experience with Workday RaaS (Report as a Service), custom report development, and WQL (Workday Query Language).
• Knowledge of HCM functional areas including Compensation, Absence Management, Organisation Hierarchies, and Job Profiles.
• Knowledge of Workday Financial functional areas including General Ledger, Accounts Payable/Receivable, Project Accounting, and Revenue Recognition.
• Proficiency in Python for building API integration pipelines and data transformations.
• Experience with Workday semi-annual release management and data model change impact assessment.
• Strong analytical and problem-solving skills with the ability to troubleshoot complex API integration failures.
• Familiarity with cloud data platforms (Databricks, Azure, or similar) and how they consume data from SaaS API sources is an advantage.
• Excellent communication skills with the ability to work across HR, Finance, IT, and engineering teams.
• Workday Integration certification or Workday Pro certification is highly desirable.

Who you are: