For you to be able to test your integration in Penneo you can use a sandbox account. Contact Penneo support to help you set up a sandbox account.
When testing signing in sandbox, you cannot use a regular electronic ID, you have to use a test eID. Be aware that they are publicly available, and therefore be careful to not send documents containing personal and sensitive data. You can find some eID's meant for testing purposes here. Below you can find some practical information.
Sandbox - https://sandbox.penneo.com/api/docs/
Production - https://app.penneo.com/api/docs/
API documentation - https://app.penneo.com/api/docs
Integration - https://penneo.readme.io/docs/getting-started
.NET SDK - https://github.com/Penneo/sdk-net
PHP SDK - https://github.com/Penneo/sdk-php
Guides to the Penneo Archive and Administrators: