One Engineer Rewrote JSONata in Go with AI in 7 Hours, Saved $500K/Year — 1,000x Speedup for $400 in Tokens

Reco.ai / Hacker News·high signal

Reco.ai published a detailed case study: a single engineer used AI to rewrite the JSONata expression evaluator as a pure-Go library called 'gnata' in seven hours, spending $400 in API tokens. The result was a 1,000x speedup on common expressions that cascaded into $500K/year in cloud cost savings across their data pipeline processing billions of events. 164 points and 147 comments on HN — the discussion is a strong signal on practical AI-assisted rewrites vs. greenfield generation.