Lexem

Built Lexem because prompt engineering deserved the same discipline we already expect from code. Lexem gives AI prompts: • Version control with commits, diffs, branching, merges, and one-click rollback • Eval + regression testing with exact match, regex, and LLM-as-judge scoring • AI-generated test cases for happy paths, edge cases, and refusals • AI diff analysis that explains prompt changes and potential risks in plain English • Eval-gated deploys across dev, staging, and prod • Token analytics per version and across prompts • SDKs for TypeScript + Python to ship prompt updates without app redeploys • Fully open-source + self-hostable on your own Postgres The goal was simple: make prompt iteration safer, testable, and production-ready.