POST Data JSON Validation in Express.js
node-validator is what you are looking for. You can use it as a standalone module like this
var check = require('validator').check;//Validatecheck('test@email.com').len(6, 64).isEmail(); //Methods are chainablecheck('abc').isInt(); //Throws 'Invalid integer'Or you can use express-validator which is built on top of node-validator as a middleware.
Here is a more recent benchmark of various JSON schema validators.
Also, for best practices you may want to check out JSON-schema which attempts to lay out a standard way of defining how a JSON object should be defined.