Why is the UniProt REST API returning multiple results, when I am only providing one ID to be checked?
it is because you do a text search and the &quot;word&quot; Q9UJL9 appears in multiple entries. If you want an id search, specifically say so and for that the query syntax is id:Q9UJL9. You will want to follow a redirect, and there are some rare cases where that might still lead to more than one entry if the id was made secondary and attached to multiple entries. e.g. P00001.