Apollo GraphQL keeps receiving requests with no queries or mutations being made

Question

I was learning GraphQL and about to finish the tutorial and this never happened before.

The problem is that the GraphQL server keeps receiving requests after opening GraphQL Playground in the browser even though no query or mutation is made.

I see these sort of responses being returned by the server:

{
    "name":"deprecated",
    "description":"Marks an element of a GraphQL schema as no longer supported.",
    "locations":[
      "FIELD_DEFINITION",
      "ENUM_VALUE"
    ],
    "args":[
      {
          "name":"reason",
          "description":"Explains why this element was deprecated, usually also including a suggestion for how to access supported similar data. Formatted using the Markdown syntax (as specified by [CommonMark](https://commonmark.org/).",
          "type":{
            "kind":"SCALAR",
            "name":"String",
            "ofType":null
          },
          "defaultValue":"\"No longer supported\""
      }
    ]
}

Answer 1

This is expected behavior.

GraphQL Playground issues an introspection query to your server. It uses the result of that query to provide validation and autocompletion for your queries. Playground will send that query to your server repeatedly (every 2 seconds by default) so that if your schema changes, these changes can be immediately reflected in the UI (although there's an issue with this feature at the moment).

You can adjust the relevant settings (click on the settings icon in the top right corner of the Playground UI) to either change the polling frequency or turn it off entirely:

  'schema.polling.enable': true, // enables automatic schema polling
  'schema.polling.endpointFilter': '*localhost*', // endpoint filter for schema polling
  'schema.polling.interval': 2000, // schema polling interval in ms

However, the behavior you're seeing is only related to Playground so it's harmless and won't impact any other clients connecting to your server.