What is Filtering?
Verified 5 August 2026
Where the filter is applied determines whether it costs or saves time. Post-filtering scores everything and discards afterwards, which is wasteful and can return fewer results than requested. Pre-filtering narrows the candidate set first, which makes heavily filtered queries faster than unfiltered ones.
Pre-filtering requires the filterable attributes to be stored as fast fields in the index. unlob writes quality, host rank, centrality, corroboration counts, content type, topic, language and both timestamps at build time, so filtering narrows before scoring.
How unlob handles this: Filtering
Common questions
What is Filtering?
Filtering restricts a search to documents matching structured criteria — date, language, domain, quality — before or during scoring.
How does Filtering work in practice?
Pre-filtering requires the filterable attributes to be stored as fast fields in the index. unlob writes quality, host rank, centrality, corroboration counts, content type, topic, language and both timestamps at build time, so filtering narrows before scoring.
See it working
The free tier is 10,000 requests a month with no card — enough to test any of this against your own queries.