schema-merging.js

import { 
  makeRemoteExecutableSchema, 
  mergeSchemas,
} from 'graphql-tools';
import {
  execute,
  HttpLink,
  makePromise,
} from 'apollo-link';

const schema1Link = new HttpLink({ uri: 'https://1jv3nzn99.lp.gql.zone/graphql' });
const schema1 = makeRemoteExecutableSchema(({ operation }) => makePromise(execute(schema1Link, operation)));
const schema2Link = new HttpLink({ uri: 'https://kwkzzz7w7.lp.gql.zone/graphql' });
const schema2 = makeRemoteExecutableSchema(({ operation }) => makePromise(execute(schema2Link, operation)));

const schema = mergeSchemas({ schemas: [schema1, schema2]});