I'm using Kubernetes with Istio which comes with traffic management. All backend api endpoints starts with /api/** followed by specific uri except frontend service. Frontend service has no any general uri prefix.

What i want to achieve is in the istio VirtualService use a regular expression that basically says, if a requested uri does not start with /api/, let it be served by frontend-service.

This is my VirtualService

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: {{ .Release.Name }}-frontend-ingress
  namespace: default
spec:
  hosts:
  {{ include "application.domain" . }}
  gateways:
  - iprocure-gateway
  http:
  - match:
    - uri:
        regex: '^(?!\/api\/).*'
    route:
    - destination:  
        host: {{ printf "%s.%s.svc.cluster.local" .Values.frontendService.serviceName .Release.Name }}
        port:
          number: {{ .Values.frontendService.service.port }}

What is the regex value that I can use to make all request that does not start with /api/ be served with frontend-service