The web interface has its own "quick filters" — for example, invoices from the last seven days. These same filters can also be used in the API by writing filter[…].
Example
GET /c/{firma}/faktura-vydana.json?filter[filterObdobi.datVyst]=filterPoslednich7Dni
On our test data, this query narrowed the selection from 1,391 invoices down to 48. The easiest way to find out a filter's name is to set it up in the web interface and look at the resulting URL.
🚨 An invalid filter is silently ignored. A typo in the field name or the value (for example, filter[filterObdobi.datVyst]=filterNesmysl) will return 200 and all 1,391 records — you won't get any error. Always compare the result against the expected count, ideally using the add-row-count=true parameter.
When it's better not to use it
This is not a documented part of the API — the feature may change or disappear at any time. For integrations, it is therefore preferable to use Filtering records with the standard bracket notation, which is part of the API and behaves predictably: an invalid field in a filter results in an error, not silent ignoring.