Superagent has a retry method which use the following status codes :

• 408
• 413
• 429
• 500
• 502
• 503
• 504
• 521
• 522
• 524

You will find the official documentation of this retry method here : https://visionmedia.github.io/superagent/#retrying-requests

Status codes 521, 522 and 524 are not supported by this lib, could it be possible to add them ?