Official data sources

Lapsight only uses free USPTO public data. Commercial patent software is not a source.

• USPTO Patent Maintenance Fee Events (PTMNFEE2)

  https://data.uspto.gov/bulkdata/datasets/ptmnfee2

  Fee-lapse detection (EXP.) and reinstatement (EXPX / PMFG)

  Weekly, cumulative, patents granted 1981-09-01 to present

• PatentsView granted-patent bulk tables (via USPTO Open Data Portal)

  https://data.uspto.gov/support/transition-guide/patentsview

  Titles, disambiguated assignees, CPC, citations, claims counts, family size

• USPTO Open Data Portal API

  https://data.uspto.gov/apis/getting-started

  Optional per-patent enrichment and bulk file discovery (API key required)

Coverage

Historical goal: every non-payment expiration event in the USPTO maintenance-fee file. Weekly jobs re-download the cumulative file and skip reinstated patents. This repository ships a real sample plus a parser so the full file can be ingested when an Open Data Portal key is configured.