Step 1.
They have both ArcPro locator and ArcMap locator.
This is arcMap one
https://transparentgov.net/json2tree/esri/server/folder2.html?org=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices&url=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices&arcgis_online_token=&select_folder=57&select_folder_text=SiteAddress+%3Csup%3EGeocodeServer%3C%2Fsup%3E&select_layer=-1&select_layer_text=SiteAddress+%3Csup%3EGeocodeServer%3C%2Fsup%3E
Step 2.
This ArcMap locator works with block search by BLK + number, I am not sure, it is customized work around or by default, until I see next ArcMap locator
https://transparentgov.net/json2tree/gateway/feature-layer/geocode-suggest-advanced-number-search.html?backgroundlayerurl=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices%2Flocators%2FSiteAddress%2FGeocodeServer&_center_lat=40.00184469531368&_center_long=-105.27926715933118&_center_zoom=20&panto=0
Step 3.
arcMap locator works with cross street search
first street full name / 1 letter of 2nd street name
NOTE: they use "INT" to indicate it is intersection, cross street point.
https://transparentgov.net/json2tree/gateway/feature-layer/geocode-suggest-advanced-number-search.html?backgroundlayerurl=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices%2Flocators%2FSiteAddress%2FGeocodeServer&_center_lat=40.0641160485373&_center_long=-105.28653915665441&_center_zoom=20&panto=0
Step 4.
arcmap locator can by default search number ( ArcPro not allow you search number, you have to add at least 1 letter after number )
https://transparentgov.net/json2tree/gateway/feature-layer/geocode-suggest.html?backgroundlayerurl=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices%2Flocators%2FSiteAddress%2FGeocodeServer&layer=SiteAddress&_center_lat=40.00166326293364&_center_long=-105.2878027312426&_center_zoom=20&panto=0
Step 5.
but arcmap does not always popup all possible results,
885 did not popup willowbrook, until you add at least 1 letter
Step 6.
885 did not popup willowbrook, until you add at least 1 letter w
Step 7.
this one is street center line as Street Address ROLE, it has street address and cross street search
https://transparentgov.net/json2tree/esri/server/folder2.html?org=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices&url=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices&arcgis_online_token=&select_folder=58&select_folder_text=StreetRangeWith40Offset+%3Csup%3EGeocodeServer%3C%2Fsup%3E&select_layer=-1&select_layer_text=StreetRangeWith40Offset+%3Csup%3EGeocodeServer%3C%2Fsup%3E
Step 8.
ArcMap locator, for street only, does not support search number only, you have to add at least one letter after number
https://transparentgov.net/json2tree/gateway/feature-layer/geocode-suggest.html?backgroundlayerurl=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices%2Flocators%2FStreetRangeWith40Offset%2FGeocodeServer&layer=StreetRangeWith40Offset&_center_lat=39.98567786115885&_center_long=-105.17595579345794&_center_zoom=20&panto=0
Step 9.
suggest does not support cross street search, so there is no popup when you typing cross street
but click find button, trigger find address candidate works.
https://transparentgov.net/json2tree/gateway/feature-layer/geocode-suggest.html?backgroundlayerurl=https%3A%2F%2Fmaps.bouldercolorado.gov%2Farcgis%2Frest%2Fservices%2Flocators%2FStreetRangeWith40Offset%2FGeocodeServer&layer=StreetRangeWith40Offset&_center_lat=39.9852098847189&_center_long=-105.17680957346114&_center_zoom=20&panto=0
Step 10.
search address number + at least 1 letter, give you approxmitely location since it is estimate
Step 11.
Step 12.
Step 13.
Step 14.
Step 15.
Step 16.
Step 17.
Step 18.
Step 19.
Step 20.