Stringly-typed code. It lurks inside quotation marks in source code, opaque to most to IDE tools, waiting for the unwary developer to rename or refactor something in their codebase. Everything builds and the app is deployed, only to throw runtime errors about references to non-existing HTTP endpoints, CSS classes, database tables, or asset files. In this talk, we'll look at the dangers of stringly-typed code. We'll see how it saps confidence in code changes, making codebases brittle. We'll look for solutions to these issues, using TypeScript to turn opaque strings into well-checked values that can be refactored with confidence.