aresource.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "http://foo.qwerty/some/schema#",
  "title": "A Resource",
  "type": "object",
  "properties": {
    "thiskeyhere": {
      "type": "string"
    },
    "aninteger": {
      "type": "integer"
    },
    "etc": {
      "type": "boolean"
    }
  }
}

someapp.py

from flask import Flask, Response, jsonify
from mypy_extensions import TypedDict
from .somewhere import datastore

app = Flask(__name__)
  

class AResource(TypedDict):
    thiskeyhere: str
    aninteger: int
    etc: bool


# See `schemas/aresource.json` for a JSON schema...
@app.route('/some/resource/<resource_id>', methods=['GET'])
def get_some_resource(resource_id: str) -> Response:
    """Get a resource, and do it with style."""
    resource: AResource = datastore.load_resource(resource_id)
    return jsonify(resource)  # type: Response