simPRO API Forum

Posted: **Wed Feb 25, 2026 9:28 pm**

I'm creating vendor receipts via the API endpoint and often get 503 errors; i.e.

Service unavailable - try again later or consider setting this node to retry automatically (in the node settings)
503 - "{\"success\":false,\"errors\":[{\"message\":\"Service Unavailable\",\"code\":503}],\"messages\":[],\"result\":[],\"resultInfo\":[]}"

A couple of questions:

Is there a rate limit for this endpoint that could lead to this error? If so what are the restrictions?

Does an API call count towards the license count; i.e. if all licenses are in use will an API call fail?

Posted: **Tue Mar 10, 2026 12:00 am**

Hi,
There is no rate limit on this endpoint, and the REST API does not have a license limit, so the 503 errors are not caused by hitting a limit.
A 503 typically indicates that the service is temporarily unavailable or unreachable.
Could you please raise a support ticket if it's still happening on your build?
Regards

simPRO API Forum

503 on HTTP POST (Create a new vendor receipt)

503 on HTTP POST (Create a new vendor receipt)

Re: 503 on HTTP POST (Create a new vendor receipt)