What are they?

Upstream error codes are returned when the data sources is not accessible. The details of these error codes can be found in the API documentation. 

What causes them?

This can happen occasionally when the government sources are unavailable/down for maintenance or performing poorly. Such incidents are rare and usually gets resolved quickly. 

How can such incidents be managed?

Upstream errors are typically intermittent. You can simply retry the transaction, without incurring any additional charges, as transactions where an upstream error was received are not billed.

Gridlines APIs are monitored on a near-real time basis and the status of APIs updated on the Gridlines status page. In case of incidents with a bigger impact, the status of the API is updated here. You can subscribe to the APIs you wish to follow, to receive an email notification whenever there is a significant incident that affects service levels. 

It is recommended to have an exception handling workflow in case the government sources are down to avoid any drop offs during on-boarding.