Senior Database Architect (SQL Server & PostgreSQL) - B2B / Freelancers

Xebia is a global AI-first, digital transformation, and engineering partner with over 25 years of experience and a team of 5,000 professionals across 16 countries. In the CEE region, the team has nearly 1,000 experts delivering modern applications, data platforms, and AI solutions for clients such as McLaren, Aviva, Deloitte, Spotify, Disney, and others. They specialize in Artificial Intelligence, Data and Cloud, Intelligent Automation, and Digital Products using technologies including AWS, Azure, GCP, Databricks, and Snowflake.

• Strong hands-on expertise in SQL Server design, indexing, query optimisation, and operational practices.
• Solid working knowledge of PostgreSQL to assess migration feasibility and compatibility.
• Proven experience optimising query and index performance in production environments.
• Experience modernising or refactoring databases behind legacy applications.
• Ability to define and set up database observability and monitoring (baselines, diagnostics, wait stats, deadlock detection, alerting).
• Pragmatic, risk-aware approach balancing improvement effort against migration cost and business risk.
• Experience assessing and scoping SQL Server to PostgreSQL migrations.
• Experience working in environments where legacy and modern systems coexist in production during transitions.
• Comfort working with Specification-Driven Development (SDD) frameworks such as OpenSpec or similar.
• Ability to produce clear, prioritized, business-readable recommendations for non-DBA stakeholders.
• Work from the European Union region with a valid work permit.

• Review the current SQL Server database design, indexes, queries, and operational practices.
• Identify performance issues, technical debt, risks, and areas that are working well.
• Recommend and prioritise pragmatic improvements.
• Assess the feasibility of migrating from SQL Server to PostgreSQL, identifying compatibility issues, risks, expected effort, and migration approaches.
• Define and implement robust database observability and performance monitoring including baselines, query diagnostics, wait statistics, blocking/deadlock detection, capacity trends, and alerting.
• Work within an AI-native engineering environment using Specification-Driven Development (SDD) frameworks such as OpenSpec to structure requirements, implementation plans, validation, and traceability.

Nice to have:

• Prior exposure to legacy 4GL or transpiled/generated codebases.
• Familiarity with .NET/Blazor application ecosystems.
• Experience with database-heavy ERP systems in payroll, billing, and scheduling domains.
• Experience in AI-assisted/AI-native engineering workflows.

Work from the European Union region and a work permit are required.