An example Azure API Management policy for Synthetic GraphQL.

graphql-policy.xml

<policies>
    <inbound>
        <base />
        <validate-graphql-request max-depth="3" />
    </inbound>
    <backend>
        <set-graphql-resolver parent-type="Query" field="getAllTodoItems">
            <http-data-source>
                <http-request>
                    <set-method>GET</set-method>
                    <set-url>https://todoitems.azurewebsites.net/tables/todoitem</set-url>
                </http-request>
            </http-data-source>
        </set-graphql-resolver>
        <set-graphql-resolver parent-type="Query" field="getTodoItem">
            <http-data-source>
                <http-request>
                    <set-method>GET</set-method>
                    <set-url>@{
		      var body = context.Request.Body.As<JObject>(true);
		      return "https://todoitems.azurewebsites.net/tables/todoitem/" + body["variables"]["id"].ToString();
                    }</set-url>
                </http-request>
            </http-data-source>
        </set-graphql-resolver>
        <set-graphql-resolver parent-type="Mutation" field="deleteTodoItem">
            <http-data-source>
                <http-request>
                    <set-method>DELETE</set-method>
                    <set-url>@{
		      var body = context.Request.Body.As<JObject>(true);
		      return "https://todoitems.azurewebsites.net/tables/todoitem/" + body["variables"]["id"].ToString();
                    }</set-url>
                </http-request>
            </http-data-source>
        </set-graphql-resolver>
        <set-graphql-resolver parent-type="Mutation" field="deleteTodoItem">
            <http-data-source>
                <http-request>
                    <set-method>POST</set-method>
                    <set-url>https://todoitems.azurewebsites.net/tables/todoitem</set-url>
		    <set-body>@{
			var body = context.Request.Body.As<JObject>(true);
			JObject jsonObject = new JObject();
			jsonObject.Add("title", body["variables"]["title"]);
			jsonObject.Add("notes", body["variables"]["notes"]);
			return jsonObject.ToString();
		    }</set-body>
                </http-request>
            </http-data-source>
        </set-graphql-resolver>
        <base />
    </backend>
    <outbound>
        <base />
    </outbound>
    <on-error>
        <base />
    </on-error>
</policies>