> For the complete documentation index, see [llms.txt](https://docs.payments.thalescloud.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payments.thalescloud.io/classic-tokenization/use-cases/post-enrolment/visa-cloud-token-framework/device-binding.md).
# Device binding
Device binding associates an end user device with a token stored on that device.
The token requestor initiates the flow with Visa Token Service (VTS). VTS then calls the issuer.
Tokenization Service translates the VTS request into [`requestDeviceBinding`](/classic-tokenization/api-reference/issuer-gateway-api/outbound-to-issuer.md).
Handle device binding like a Tokenization (digitization) request. The issuer computes a trust level and returns a GREEN, YELLOW, or RED decision.
You can request device binding only for an existing token.
For a YELLOW decision, Visa requires the issuer to support at least one of these ID\&V methods:
* OTP via SMS or email
* Call customer care
* Verify in the issuer application
* 3DS
If you use issuer-application verification, the issuer and token requestor must agree on a protocol. This protocol lets the two applications exchange an authentication token.
Visa defines and validates the authentication token format. The token is a JSON Web Token (JWT).
The issuer and Visa exchange certificates. The issuer uses its certificate to sign the JWT. The token requestor sends the JWT to VTS. VTS verifies the signature.
When device binding completes, VTS sends a notification with the result. Tokenization Service translates it into [`notifyVirtualCardChange`](/classic-tokenization/api-reference/issuer-gateway-api/outbound-to-issuer.md).
The sequence diagram shows the end-to-end flow.
Device binding initiated by the token requestor:
Device binding initiated by the token requestor
{% hint style="info" %}
You can manage the ID\&V method list dynamically by omitting `idvMethodList` in the `requestDeviceBinding` response.
With this approach, every time VTS requests the ID\&V method list, Tokenization Service calls [`getIDnVMethodList`](/classic-tokenization/api-reference/issuer-gateway-api/outbound-to-issuer.md).
If you include `idvMethodList` in the `requestDeviceBinding` response, Tokenization Service caches it for the current session. It then returns it to VTS as needed, without calling `getIDnVMethodList`.
{% endhint %}
Either the issuer or the token requestor can remove the binding between the token and the device.
This is depicted in the two flows below.
Unbind initiated by the issuer:
Unbind initiated by the issuer
Unbind initiated by the token requestor:
Unbind initiated by the token requestor
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.
Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:
```
GET https://docs.payments.thalescloud.io/classic-tokenization/use-cases/post-enrolment/visa-cloud-token-framework/device-binding.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
