api-client/netlify/api.js

// Docs on event and context https://www.netlify.com/docs/functions/#the-handler-method
exports.handler = (event) => {
  switch (event.httpMethod) {
    case "GET":
      try {
        const name = event.queryStringParameters.name || "World"
        return {
          statusCode: 200,
          headers: {
            "Content-Type": "application/json",
          },
          body: JSON.stringify({ message: `Hello ${name}` }),
        }
      } catch (e) {
        return { statusCode: 500, body: e.toString() }
      }

    default:
      return { statusCode: 405, body: "Method Not Allowed" }
  }
}