HTTP Status Codes in ServiceNow Integrations: What Each One Means and How to Handle It

2xx Success codes

200 OK — request succeeded, body contains the result. Standard for GET and PATCH.

201 Created — resource was created, body contains the new resource. Standard for POST. Check Location header for the new resource URL.

204 No Content — success with no response body. Standard for DELETE. Don't try to parse the body — there is none.

4xx Client error codes

400 Bad Request — your request is malformed. Check: JSON syntax, required fields, field value formats. Fix your request, not a retry situation.

401 Unauthorized — authentication failed. Token is missing, expired, or invalid. Refresh the token if using OAuth; otherwise check credentials.

403 Forbidden — authenticated but not permitted. The user/service has no ACL access to this resource. Not fixable with retry — requires permission change.

404 Not Found — the resource does not exist. The sys_id you referenced may have been deleted, or you have a URL typo.

422 Unprocessable Entity — request syntax is correct but semantic validation failed. A field value doesn't match allowed values, a reference doesn't exist, etc.

429 Too Many Requests — rate limited. Check the Retry-After header if present. Implement exponential backoff.

5xx Server error codes

500 Internal Server Error — the server crashed processing your request. Often a bug on the remote end. Log and retry with backoff.

503 Service Unavailable — service is down or overloaded. Retry with backoff, alert if persistent.

Handling in ServiceNow scripts

var response = rm.execute();
var status = response.getStatusCode();

if (status >= 200 && status < 300) {
    // Success - process response
} else if (status == 401) {
    // Re-authenticate
    refreshOAuthToken();
} else if (status == 429) {
    // Rate limited - queue for retry
    gs.eventQueue('integration.retry', current, rm.getEndpoint(), '');
} else if (status >= 500) {
    // Server error - log and retry
    gs.error('External service error: ' + status);
} else {
    // 4xx client error - log and do not retry
    gs.error('Request error: ' + status + ' - ' + response.getBody());
}