JSON Web Tokens are an open, industry standard RFC 7519 method used to represent claims securely between two parties. JWT.IO allows you to decode, verify, and generate a JSON Web Token. https://jwt.io
JSONLint
Validates the structure of a JSON file. JSONLint validates and reformats JSON, a lightweight data-interchange format. Copy and paste, directly type, or input a URL in the editor and let JSONLint tidy and validate your messy JSON code. https://jsonlint.com