PostgREST is great and really reduces the boilerplate around building REST APIs. They recommend implementing access rules and extra business logic using PostgreSQL-native features (row level security, functions etc) but once you get your head around that, it really speeds things up!
If you're interested in playing around with a PostgREST-backed API, we run a fork of PostgREST internally at Splitgraph to generate read-only APIs for every dataset on the platform. It's OpenAPI-compatible too, so you get code and UI generators out of the box (example [0]):
$ curl -s "https://data.splitgraph.com/splitgraph/oxcovid19/latest/-/rest/epidemiology?and=countrycode.eq.GBR,adm_area_3.eq.Oxford)&limit=1&order=date.desc"
[{"source":"GBR_PHE","date":"2020-11-20", "country":"United Kingdom", "countrycode":"GBR", "adm_area_1":"England", "adm_area_2":"Oxfordshire", "adm_area_3":"Oxford", "tested":null, "confirmed":3079, "recovered":null, "dead":41, "hospitalised":null, "hospitalised_icu":null, "quarantined":null, "gid":["GBR.1.69.2_1"]}]