What causes 'unexpected token' or 'invalid control character' errors in JSON and how can I resolve them?

These errors typically indicate a fundamental syntax issue. An 'unexpected token' often means the parser encountered a character it didn't expect, such as a missing comma, unquoted string values, using single quotes instead of double quotes, or extra characters outside the main JSON structure. An 'invalid control character' usually points to unescaped special characters within string values (e.g., a raw newline `\n`, tab `\t`, backslash `\`, or double quote `\"` that is not properly escaped with a preceding backslash). Resolution involves carefully inspecting the JSON string at the reported error location, using a JSON linter, or programmatically escaping problematic characters (e.g., using `json.dumps` in Python or `JSON.stringify` in JavaScript).