The asset transfers backend exposes an HTTP API.
The API is documented using the OpenAPI specification, allowing to easily generate client libraries for commonly-used programming languages. We use https://github.com/openapitools/openapi-generator to generate our client libraries.
The latest version of the API specification is available here.
Note that in usual deployment scenarios, the backend is protected by an API token, configured as a x-auth-token header in every HTTP request.