graphql-http package does not provide an out-of-a-box GraphqQL Playground.

Only GraphQL over HTTP and this issue

This is the official GraphQL over HTTP spec reference implementation and as such follows the specification strictly without any additional features (like playgrounds or GUIs, file uploads, @stream/@defer directives and subscriptions).

You can use graphql-playground-middleware-express to expose an endpoint for the GraphQL Playground.

E.g.

const express = require('express');
const { createHandler } = require('graphql-http/lib/use/express');
const expressPlayground =
  require('graphql-playground-middleware-express').default;
const { GraphQLSchema, GraphQLObjectType, GraphQLString } = require('graphql');

/**
 * Construct a GraphQL schema and define the necessary resolvers.
 *
 * type Query {
 *   hello: String
 * }
 */
const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'Query',
    fields: {
      hello: {
        type: GraphQLString,
        resolve: () => 'world',
      },
    },
  }),
});

const app = express();

app.all('/graphql', createHandler({ schema }));
app.get('/playground', expressPlayground({ endpoint: '/graphql' }));

app.listen(4000, () => console.log('Server is running on PORT 4000...'));

Access https://so76735343-0n0m--4000--c53ab388.local-corp.webcontainer.io/playground endpoint, you will see GraphQL playground UI.

stackblitz