Vouchery API implements pagination as described in RFC5988 using Link HTTP header. When a collection resource is requested and number of results exceeds default per_page setting response will include following headers
Link:
<https://preview.vouchery.io/api/v1.0/campaigns/2/vouchers?page=2&per_page=100>; rel="next",
<https://preview.vouchery.io/api/v1.0/campaigns/2/vouchers?page=2&per_page=100>; rel="last"
Total-Count: 149
Each endpoint can have it's own per_page setting. For more examples head over to GitHub which uses the same pagination scheme.