Here is a short guide on how to create API calls using CURL for a reference. Result will be presented as json and in debug mode.

Enable API and create new API key

Go to settings in phpipam GUI and enable API module, than go to settings > API and create new API App, set all APP params as desired for you APP.

Authentication

First we need to authenticate to API server by providing username/password from some valid phpipam account to receive token:
curl -X POST --user test:test123 http://devel.phpipam.net/api/apiclient/user/ -i
HTTP/1.1 200 OK
Content-Length: 116
Content-Type: application/json

{"code":200,"success":true,"data":{"token":".J1e9ipFZkPE6EvIRAqEf9hp","expires":"2017-01-05 14:18:43"},"time":0.009}%
After authentication in succesfull you receive token that you need to include in each following rquest. In our case the token is .J1e9ipFZkPE6EvIRAqEf9hp. We can also see that token expires in 6 hours.

To extend token validity make a POST or PATCH request to server with token (or phpipam-token) http header "token: .J1e9ipFZkPE6EvIRAqEf9hp":

curl -X PATCH http://devel.phpipam.net/1.3/api/apiclient/user/ --header "token: .J1e9ipFZkPE6EvIRAqEf9hp" -i
HTTP/1.1 200 OK
Content-Type: application/json

{"code":200,"success":true,"data":{"expires":"2017-01-05 14:56:22"},"time":0.005}%

Some example calls

Get details for specific subnet (set links=false to hide links):

curl http://devel.phpipam.net/1.3/api/apiclient/subnets/22/\?links\=false --header "token: .J1e9ipFZkPE6EvIRAqEf9hp" -i
HTTP/1.1 200 OK
Content-Length: 898
Content-Type: application/json

{"code":200,"success":true,"data":{"id":"22","subnet":"77.53.31.128","mask":"27","sectionId":"4","description":"Test swedish","linked_subnet":null,"firewallAddressObject":null,"vrfId":"0","masterSubnetId":"0","allowRequests":"0","vlanId":"0","showName":"0","device":"0","permissions":"{\"2\":\"1\",\"3\":\"3\",\"4\":\"3\"}","pingSubnet":"0","discoverSubnet":"0","DNSrecursive":"0","DNSrecords":"0","nameserverId":"0","scanAgent":"0","isFolder":"0","isFull":"0","tag":"2","threshold":"0","location":null,"editDate":"2016-07-18 20:02:30","customer_type":null,"customer_address_type":null,"csid":null,"calculation":{"Type":"IPv4","IP address":"\/","Network":"77.53.31.128","Broadcast":"77.53.31.159","Subnet bitmask":"27","Subnet netmask":"255.255.255.224","Subnet wildcard":"0.0.0.31","Min host IP":"77.53.31.129","Max host IP":"77.53.31.158","Number of hosts":30,"Subnet Class":false}},"time":0.006}%

Update subnet description (using JSON data):

curl -X PATCH --data '{"description":"Test swedish2"}' http://devel.phpipam.net/1.3/api/apiclient/subnets/22/ --header "token: .J1e9ipFZkPE6EvIRAqEf9hp" --header "Content-Type: application/json" -i
HTTP/1.1 200 OK
Content-Length: 66
Content-Type: application/json

{"code":200,"success":true,"message":"Subnet updated","time":0.01}%

Update subnet description (using form-encoded data):

curl -X PATCH --data 'description="Test%20Swedish' http://devel.phpipam.net/1.3/api/apiclient/subnets/22/ --header "token: .J1e9ipFZkPE6EvIRAqEf9hp" --header "Content-type: application/x-www-form-urlencoded" -i
HTTP/1.1 200 OK
Server: Apache/2.4.23 (FreeBSD) OpenSSL/1.0.2j
Content-Length: 67

{"code":200,"success":true,"message":"Subnet updated","time":0.008}%


Request fist available subnet with mask /29 inside specific subnet:

curl -X GET http://devel.phpipam.net/api/apiclient/subnets/92/first_subnet/29/ --header "token: .J1e9ipFZkPE6EvIRAqEf9hp" -i
HTTP/1.1 200 OK
Content-Type: application/json
token: .J1e9ipFZkPE6EvIRAqEf9hp

{"code":200,"success":true,"data":"192.168.20.16\/29"}


Create new subnet with first available /29 mask using POST request:

curl -X POST http://devel.phpipam.net/api/apiclient/subnets/92/first_subnet/29/ HTTP/1.1 --header "token: .J1e9ipFZkPE6EvIRAqEf9hp" -v
HTTP/1.1 201 CREATED
Content-Type: application/json
token: .J1e9ipFZkPE6EvIRAqEf9hp

HTTP/1.1 201 Created
Location: /api/apiclient/subnets/771/
Content-Length: 51
Content-Type: application/json

{"code":201,"success":true,"data":"Subnet created", "id":51}