Thanks @radekmie. It does use JSON Schema.

It's the same Guest Schema code sample from the tutorials posted on your official website. The only difference is that the schema itself comes from a string stored in MySQL. What seems to be happening are some kind of invisible characters being added during the journey when it's stored and retrieved in MySQL. The result is that the JSON from the MySQL db query is always treated like a string by the browser - even when run through JSON.parse(JSON.stringify(schema)).

Code:

Sample schema stored in db field
(shortened some fields just to fit in this window):

{
      title: 'Guest',
      type: 'object',
      properties: {
        lastName: { type: 'string' },
        workExperience: {
          description: 'Work experience in years',
          type: 'integer',
          minimum: 0,
          maximum: 100,
        },
        profession: {
          type: 'string',
          options: [
            {
              label: 'Developer',
              value: 'developer',
            },
            {
              label: 'Tester',
              value: 'tester',
            },
          ],
        },
        additionalInfo: {
          type: 'string',
          uniforms: { component: LongTextField },
        },
      },
      required: ['lastName'],
    };

//Code from pages/[pageurl].tsx

function createValidator(schema: object) {
  const validator = ajv.compile(schema);

  return (model: object) => {
    validator(model);
    return validator.errors?.length ? { details: validator.errors } : null;
  };
}

let res = await fetch(`/api/formbuilder?id=${id}`, { method: 'GET' });
let json = await res.json();

//this is the schema being returned from the MySQL query
var s = json[0][0].schema;

// remove hidden, non-printable and other non-valid JSON chars
s = s.replace(/\\n/g, "\\n") ;
.replace(/\\'/g, "\\'");
 .replace(/\\"/g, '\\"');
.replace(/\\&/g, "\\&");
 .replace(/\\r/g, "\\r");
 .replace(/\\t/g, "\\t");
.replace(/\\b/g, "\\b");
.replace(/\\f/g, "\\f");
s = s.replace(/[\u0000-\u0019]+/g,""); 

const ajv = new Ajv({ strict: false, allErrors: false, useDefaults: true });

s = JSON.parse(JSON.stringify(s));

const schemaValidator = createValidator(s);

const schema = new JSONSchemaBridge(s, schemaValidator);

Resulting console log:

https://ibb.co/H4MVgcw

• top is the database response pasted from above (interpretted like a String)
• bottom is the same schema when explicitly called within react (interpretted like an Object)