Error Codes

0 -- '' (empty message string means OK)
101 -- 'Unknown error'
1102 -- 'Invalid username'
1204 -- 'Not a valid Short URL hash'
1206 -- 'URL you tried to shorten was invalid'
1215 -- 'Short URL is not correct or existed'
1216 -- 'URL you tried to shorten is not allowed'
1217 -- 'Access Denied'
1218 -- 'Short URL is not correct'
1219 -- 'Target server on cooldown'
1220 -- 'URLs limit has been reached'
1221 -- 'Exceeded limit of batch operation'
1300 -- 'Invalid API key'
1301 -- 'Invalid resource'
1302 -- 'Method not supported'
1303 -- 'API call limit reached'
1305 -- 'Missing input parameters'
1306 -- 'URL not found in DB'
1307 -- 'Wrong number of input parameters'
1308 -- 'HTTP error'
1309 -- 'Tag not found'
1310 -- 'Too big POST data'
1311 -- 'Invalid or duplicate tag label'
1312 -- 'Invalid date'
1313 -- 'Domain not found'
1314 -- 'Invalid webhook parameter'
1315 -- 'Requested domain not allowed for this API key'
1316 -- 'Unsupported request Content-Type or missing Content-Type request header'
1317 -- 'Error in Smart Link rules'

Example error response:

{
  "error": {
    "code": 1300,
    "message": "Invalid API key"
  }
}

HTTP status code - 400 Bad Request.

Other 40x and 50x codes may be also used.