$ curl -si -X POST /api/v1/urls -d '{"url":"https://example.com/one","alias":"demo-link"}'
HTTP/1.1 201 
X-RateLimit-Remaining: 4
Location: http://localhost:8080/demo-link
{"code":"demo-link","shortUrl":"http://localhost:8080/demo-link","expiresAt":null}

$ curl -si -X POST /api/v1/urls -d '{"url":"https://example.com/two","alias":"demo-link"}'
HTTP/1.1 409 
X-RateLimit-Remaining: 3
{"detail":"alias already taken: demo-link","instance":"/api/v1/urls","status":409,"title":"Conflict"}

$ curl -si -X POST /api/v1/urls -d '{"url":"ftp://example.com/file"}'
HTTP/1.1 400 
X-RateLimit-Remaining: 2
{"detail":"only http and https URLs are allowed","instance":"/api/v1/urls","status":400,"title":"Bad Request"}

$ curl -si -X POST /api/v1/urls -d '{"url":"https://example.com","alias":"api"}'
HTTP/1.1 400 
X-RateLimit-Remaining: 1
{"detail":"alias must be 4-32 chars of A-Z a-z 0-9 _ -","instance":"/api/v1/urls","status":400,"title":"Bad Request"}