The SKULabs shipping APIs are some of the most monitored and robust that we offer. Whenever you request rates or labels in SKULabs you're using the SKULabs shipping API.
The time it takes for SKULabs to handle any shipping request is under 1/100th of a second even under peak and double-peak loads but the bulk of a shipping request will be spent waiting on the carrier APIs to reply to our servers.
Typical response times are as follows, but these numbers vary by integration. For instance, FedEx is offered through Shippo, EasyPost, Amazon, and SKULabs own direct integration with FedEx and each of these APIs have their own interface with FedEx themselves.
USPS - 1 second
FedEx - 2 seconds
UPS - 3 seconds
Stamps/Endicia - 2-4 seconds
Amazon UPS/FedEx - 5 seconds
Sometimes, your carrier themselves or the integration such as Amazon or EasyPost experience technical issues or a higher-than-average volume of requests and will take longer than usual to respond.
How can I tell if I'm impacted?
If you are experiencing a delay in seeing the rates screen appear, that means that one or more of your shipping carriers may be experiencing delays. When this happens you may see a recommendation inside of the rates screen...
Recommendation: Amazon took 45.3 seconds to reply, you may want to temporarily disable this carrier in your shipping settings.
How to temporarily disable a slow carrier
You can disable carriers from your shipping settings page or you can wait and try again later when their API may no longer be impacted.
How to tell if this is part of a wider outage
Check your carrier's status page or other sites that take reports of websites being down such as www.downdetector.com
EasyPost: https://www.easypoststatus.com/ (Multiple carriers)
Shippo: https://status.goshippo.com (Multiple carriers)
Amazon BuyShipping: http://status.mws.amazon.com/ (Check the Merchant Fulfillment APIs section)