Sr. Software Engineer

# Sr. Software Engineer Apply Apply Posted  5 days agoShare

Seattle, WA $65 Hourly
** Overview
* * Our client is undergoing a large-scale ERP transformation, migrating from a legacy system to Microsoft Dynamics 365 Finance & Operations (D365 F&O). This Senior Software Engineer will play a critical role in that initiative, owning the data migration workstream while supporting non-middleware integration efforts across the program.  You’ll partner closely with the Integration Program Lead and a small, focused engineering team, working across legacy SQL/SSIS systems, modern APIs, and cloud-based tools.

This is a high-impact, high-visibility role tied to a program with a defined go-live timeline.

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- ** What You’ll Do
** Data Migration  Design and build SQL-based migration scripts to extract, transform, and load data into D365 F&O.  Partner with functional leads and data owners to define and validate field-level mapping.  Execute mock migrations, reconcile outputs, and track defects through resolution.  Build and maintain validation frameworks to ensure data completeness and accuracy at go-live.  Support cutover planning, including sequencing, timing, and rollback validation.  

Legacy System Modernization (SQL / SSIS)  Assess existing SSIS packages and SQL Server Agent jobs to determine what should be migrated or retired.  Refactor legacy ETL pipelines to align with modern infrastructure and D365 requirements.  Document embedded logic within legacy systems that may lack formal documentation.  Collaborate with integration engineers to transition logic from SQL-based workflows to API-driven patterns where appropriate.  

Backend & API Development  Build supporting backend services, utilities, and tooling to fill integration gaps.  Develop and extend D365 F&O data entities, DMF packages, and OData integrations.  Write and maintain utility scripts (C#, Python, or Power Shell) for migration and operational support.  Support development of test harnesses, data seeding tools, and QA automation.  Collaboration & Documentation  Contribute to technical design documents, data mapping specifications, and operational runbooks.  

Participate in design reviews and proactively identify risks.  Partner with business stakeholders to understand data structures and transformation requirements.  Operate with a documentation-first mindset to ensure long-term maintainability.

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- ** What You Bring  Required
** 5–8 years of experience in backend or data-focused software engineering roles  Advanced SQL expertise (complex joins, window functions, stored procedures, performance tuning)  Hands-on experience with SSIS and SQL Server Agent jobs  Experience delivering large-scale data migration efforts (ETL, reconciliation, cutover)  Proficiency in C#  Strong debugging and root-cause analysis skills across complex systems  Ability to work through ambiguous or undocumented legacy environments  Clear and effective technical documentation skills--
- ** Highly Preferred
** Experience with Microsoft Dynamics 365 F&O (DMF, data entities, OData APIs, or X++)  Background working with legacy ERP systems in regulated or complex environments  

Experience with Azure data tooling (Data Factory, Synapse, etc.)  Familiarity with API-based integrations (REST, JSON, OAuth 2.0)  Prior involvement in enterprise-scale ERP implementations or migrations--
- ** Nice to Have
** Exposure to Mule Soft or similar integration platforms (conceptual understanding)  

Experience with Azure Dev Ops for backlog management and CI/CD  Background in construction, engineering, or related industries
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