# Capturing groups when using Kong Ingress Controller **URL:** \ **Category:** General\ **Tags:** kubernetes, kong-gateway\ **Created:** [September 11, 2019, 1:54am UTC](https://discuss.konghq.com/t/capturing-groups-when-using-kong-ingress-controller/4405 "2019-09-11T01:54:37Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![hbagdi](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.konghq.com/hbagdi/32/562_2.png) [@hbagdi](https://discuss.konghq.com/u/hbagdi)\ **Post date:** [September 11, 2019, 6:29am UTC](https://discuss.konghq.com/t/capturing-groups-when-using-kong-ingress-controller/4405/2 "2019-09-11T06:29:44Z")
Please have a look at the following post: > [@Kong ingress controller and path based routing](https://discuss.konghq.com/t/kong-ingress-controller-and-path-based-routing/2956/6): > > It turns out that [Ingress Spec](https://github.com/kubernetes/kubernetes/blob/7d75b73e1d72cef7a0f0e2804f8e0a582ccb6b61/staging/src/k8s.io/api/networking/v1beta1/types.go#L170-L178) supports the POSIX regular expression (as defined by IEEE Std 1003.1) and not PCRE, which is used by Kong. This means that you can use only a subset of regular expressions that are valid POSIX regexes. Since, it’s an ID that you are trying express, I imagine it would be possible for you to know which characters can be present in the ID? The following Ingress is satisfied and works properly for me, and you can build up on top of it: apiVersion: extensions/v1beta… The regex supported by Ingress spec are POSIX based and not PCRE. --- _[View the full topic](https://discuss.konghq.com/t/capturing-groups-when-using-kong-ingress-controller/4405)._