npm install -g get-graphql-schema

  Usage: get-graphql-schema [OPTIONS] ENDPOINT_URL > schema.graphql
  Fetch and print the GraphQL schema from a GraphQL HTTP endpoint
  (Outputs schema in IDL syntax by default)
  Options:
    --header, -h    Add a custom header (ex. 'X-API-KEY=ABC123'), can be used multiple times
    --json, -j      Output in JSON format (based on introspection query)
    --version, -v   Print version of get-graphql-schema