REST API - Support and limitations
The Cisco IOS XE REST API is supported on specific platforms, including the CSR 1000V and ASR1000 series routers. This API provides an alternative to the Cisco IOS XE CLI for provisioning selected functions. However, it is important to note that REST API support is limited to IOS XE versions up to 16.6. For versions 16.7.x and above, Cisco recommends using RESTCONF instead of the REST API.
Links:
https://forum.networklessons.com/t/introduction-to-rest-api/8357/28?u=lagapidis
https://networklessons.com/cisco/ccna-200-301/introduction-to-rest-api
https://networklessons.com/cisco/evolving-technologies/device-programmability#RESTCONF