What is Fast field?
Verified 5 August 2026
Attributes you filter or sort on — dates, scores, categories, numeric signals — are stored in a column layout rather than inside documents, so a filter reads a contiguous array instead of decoding records.
This is why filtering can make a query faster rather than slower: the candidate set narrows before scoring, and the narrowing itself is nearly free.
unlob stores quality, host rank, centrality, community, independent source counts, in-degree, both timestamps, content type, topic and language as fast fields.
How unlob handles this: Filtering
Common questions
What is Fast field?
A fast field is a document attribute stored column-wise in the index for direct lookup, enabling filtering and sorting without reading the document.
How does Fast field work in practice?
This is why filtering can make a query faster rather than slower: the candidate set narrows before scoring, and the narrowing itself is nearly free.
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.