Data Contracts in Production: Stop Trusting Your Upstream Sources (opens in new tab)

Your upstream data source changed a column type last night. Your pipeline ran at 2am, ingested everything without a single error, and by the time your stakeholders opened their dashboards at 9am, the revenue numbers were wrong. No alert fired. No test failed. The pipeline was technically healthy. This is the most common and expensive failure mode in data engineering, and it happens because we build systems that trust the data they receive. Data contracts are the fix. What a Data Contract Actu...