> **Description:** Illustrated guides showing the agreement sign-up, charge, and payment source flows for PSPs using card passthrough.

> **AI agent:** Read [https://developer.vippsmobilepay.com/docs/knowledge-base/ai-tools.md](https://developer.vippsmobilepay.com/docs/knowledge-base/ai-tools.md) first. It covers keeping API keys and secrets out of generated code.

> **Full site overview:** For an overview of the entire site, read [https://developer.vippsmobilepay.com/llms.txt](https://developer.vippsmobilepay.com/llms.txt).

# How it works

How subscription agreement sign-up and charging work for PSPs using card passthrough with the Recurring API.

The following guides illustrate the three main flows:

- [How agreement sign-up works](https://developer.vippsmobilepay.com/docs/APIs/psp-recurring-api/how-it-works/agreement-sign-up.md)
- [How charge creation works](https://developer.vippsmobilepay.com/docs/APIs/psp-recurring-api/how-it-works/charge-creation.md)
- [How payment source updates work](https://developer.vippsmobilepay.com/docs/APIs/psp-recurring-api/how-it-works/payment-source-update.md)

## More information

- For technical details, see the [Recurring PSP API guide](https://developer.vippsmobilepay.com/docs/APIs/psp-recurring-api/recurring-psp-api-guide.md)
- For more agreement and charge flow examples, see
  [How the Recurring API works](https://developer.vippsmobilepay.com/docs/APIs/recurring-api/how-it-works/README.md)