Spec Diff
Product specs get revised in place and re-sent without a changelog. Spec Diff compares any two revisions of a spec document and reports what actually moved — dimensions, tolerances, materials — ignoring reflowed layout.
- Year
- 2025
- Role
- Build
- Built with
- Python, pdfplumber, Postgres
- 12k
- documents indexed
- 31
- silent revisions caught in month one
The problem
A supplier sends revision C. Nothing in the filename or the email says which of the 40 fields changed from revision B. Someone finds out at the sampling stage, which is the expensive place to find out.
Approach
Text diffing was useless — regenerated PDFs reflow constantly, so every line looks changed. Instead the extractor pulls specs into a normalised field map with units resolved, then diffs the maps. A tolerance written as "±0.5mm" and "+/- 0.5 mm" has to compare equal or the output is noise.
The report leads with the fields that carry cost or tooling implications, because that is the question the reader actually has.