> For the complete documentation index, see [llms.txt](https://docs.vida.id/identity-stack/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vida.id/identity-stack/sign/digital-signature/vsp-openapi/api-reference.md).

# API Reference

## VSP Open API Workflow

1. **Get Access to VIDA Sign Platform and Generate API Keys**\
   The client requests access to the VIDA Sign platform and generates API keys needed to interact with the platform’s API securely.
2. **Authentication**: Begin by obtaining an access token through the Authentication API. This token will be used for secure access to the VSP Open API.
3. **Document Upload (for Multiple Documents)**:

   * For transactions involving multiple documents, use the Upload Document API to upload each document individually. This generates unique `document_ids` for each document.
   * These `document_ids` can then be added to an envelope in the next step.

   If only a single document is required, this step can be skipped, and the document can be added directly during envelope creation.
4. **Envelope Creation**:
   * **Multiple Documents**: Use the Create Envelope API to group the uploaded `document_ids` into a single envelope, preparing them for signing by one or more recipients.
   * **Single Document**: If only a single document is involved, it can be directly added during the envelope creation process, bypassing the document upload step.
5. **Envelope Distribution**: VIDA handles the secure distribution of the envelope via email or URL, ensuring that recipients can easily access and sign the documents.
6. **Signer Authentication**:
   * If the signer’s identity has not been verified, they will undergo a KYC (Know Your Customer) verification process. Use the KYC Verification API to perform this step.
   * Once verified (or if already verified), the signer proceeds to review the document(s) for signing.
7. **Document Signing**:
   * The signer reviews the document(s) in the provided preview interface. VIDA handles the UI for the signature style and placement.
   * The signer then authenticates using either an SMS OTP or biometric verification.
8. **Tracking and Document Retrieval**:
   * After the document is signed, track the status of the signing process.
   * Once completed, use the Download Signed Document API to retrieve the signed document(s).