The standard way to call a third-party endpoint in your workflow is by using context.call. However, if you need to call the Resend endpoint to send emails (/emails or /emails/batch), you can leverage the type-safe method context.api.resend.call method:
context.api.resend.call is not yet available in workflow-py. You can use context.call instead to work with Resend. See our Roadmap for feature parity plans and Changelog for updates.
const { status, body } = await context.api.resend.call(
  "Call Resend",
  {
    token: "<RESEND_API_KEY>",
    body: {
      from: "Acme <onboarding@resend.dev>",
      to: ["delivered@resend.dev"],
      subject: "Hello World",
      html: "<p>It works!</p>",
    },
    headers: {
      "content-type": "application/json",
    },
  }
);
The SDK provides predefined types for the body field in both the request parameters and the response, simplifying common use cases. If you need to customize these types, you can override them as shown below: 
type IsBatch = true; // Set to either true or false
type ResponseBodyType = { ... }; // Define your response body type
type RequestBodyType = { ... };  // Define your request body type

const { status, body } = await context.api.resend.call<
  IsBatch,
  ResponseBodyType,
  RequestBodyType
>(
  "Call Resend",
  {
    ...
  }
);