Case study / 
Walmart Global Tech India
Moving millions. Keeping identity connected.
A production-user migration, a new database, and a more connected sign-in experience across global markets.
Senior Software Engineer · IAM Team
Production identity migration across multiple global markets, including SSO and legacy authentication issues.
production users migrated
Total production user identities migrated to a new database.
Identity infrastructure sits on a critical path: it connects people to the systems they use. The WCP initiative brought production users onto a new database while addressing legacy authentication issues and enabling single sign-on.
Led the migration of 7.5 million production users to a new database.
Designed and executed migration strategies for multiple global markets.
Helped achieve SSO and resolve legacy authentication issues.
Coordinated sprint planning, resources, and reporting with senior management.
The delivered scope and outcome are based on my professional experience. Internal benchmarks, production topology, rollout records, and alternative evaluations are not published here. The engineering considerations below describe how I reason about this class of system; they do not assert undisclosed implementation details.
Engineering considerations for this class of system. The delivered work is described in the contribution and implementation sections.
Moving records establishes progress; matching identity coverage and authentication behavior establishes correctness. For this class of migration, compare record reconciliation with sign-in success, error trends, and a clearly defined recovery boundary. A rollout should advance because evidence supports it, rather than because a batch completed.
Google SRE: evaluating a staged rollout (opens in a new tab)SSO connects authentication, authorization, and session behavior. Review which identifiers remain stable, how existing sessions behave during a transition, and which authorization guarantees must survive the database change. OAuth security guidance is relevant when OAuth is part of the identity flow; it does not establish which protocol this project used.
IETF: OAuth 2.0 security best practices (opens in a new tab)A production migration changes a live service, not just data at rest. Coordinating the transition across markets and keeping authentication connected are important parts of the engineering problem.
7.5 million production users migrated, with SSO enabled and legacy authentication issues addressed.
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