Vibe porting: AI-assisted cross-language rewrites enabled by existing test suites¶
Insight: "Vibe porting" — using AI to rewrite an existing codebase in a different language — is viable when comprehensive test suites exist to validate behavioral equivalence. Reco's team completed a Go implementation of JSONata (a JSON expression language) in approximately 7 hours for roughly $400 in token spend, verified via the existing test suite and a week-long shadow deployment confirming exact behavioral match.
Detail: The headline "$500K/year savings" is acknowledged as hyperbolic framing — actual costs were $400 in tokens plus engineering time for deployment validation. The key enabler was comprehensive existing test coverage, not AI capability alone. Without tests, validating cross-language behavioral equivalence would require exhaustive manual verification. This positions test-driven development as infrastructure that unlocks AI-assisted migration at scale.