credit: https://my.kualo.com/uk/knowledgebasekualo.php?kbcat=0&article=120 Was trying to with a strong verify token. Somewhat like this: setup FB messenger webhook o\/ERviEE\/vt0|<E|\| The same is been verified in the code: req.query['hub.verify_token'] === 'o\/ERviEE\/vt0|<E|\|' However, the value received from FB is: o\\/ERviEE\\/vt0|<E|\\| . There seems to be no reference as such which talks about how escapes special characters for verify tokens or alike. Not sure if this happens for other entities as well. This is strange document Facebook Conclusion: need to be a little bit cautious when using special characters for verify tokens. Originally published at xameeramir.github.io .