Freelance Data Developer

A UK retail and ecommerce business needs a freelance data developer to finish building a single source of truth on an existing SQL Server database. The core trading data is already in and reconciling: point of sale, stock, footfall and web sales. Your job is to bring in the systems that are not yet connected, join them cleanly into the model, and make sure every number reconciles to the reports the business already trusts. What you would be doing Extending an existing SQL Server database on a private network. The hard part is done and proven, so you are joining something that works rather than starting from nothing. Connecting the remaining systems by API and direct query: Shopify, the finance systems, and the smaller marketing and service platforms. Building conformed dimensions and fact tables. One date, one product, one location, one customer, shared across every source. Writing governed SQL views so the business logic lives in one place rather than being repeated. Reconciling every source to a known good total before it is signed off. This is central to the role, not a tidy up at the end. Documenting as you go and handing over cleanly, so the work does not depend on you staying. You should be strong in SQL Server and T-SQL: views, stored procedures, query tuning, linked servers. Data modelling, warehouse style, with conformed dimensions and facts. ETL or ELT: scheduled, incremental, re-runnable loads that never double count. REST API integration, including auth, paging and rate limits. A reconciliation mindset. You care that a number is correct, not just that it moved. Clear documentation and handover. Useful but not essential Retail or ecommerce data: sales, returns, stock, margin, multi-channel. Experience with finance system integrations, or with cross border and marketplace feeds. How we work Everything in source control from day one. If a definition is not confirmed you ask rather than guess, because a confident wrong number is worse than an honest gap. One source proven end to end before the next is started. The engagement Freelance and remote friendly, priced in phases. We would start with a contained first piece: confirm the current state, then bring in one source end to end and reconcile it. If that goes well, the rest follows the same pattern. Some work touches a private network and may need a device we provide. In your proposal, please tell us Similar work you have done, particularly building a reconciled source of truth across several systems. Your day rate and a rough price for that first piece. And one example of a data problem you caught that others had missed. We are more interested in that than a long CV.