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Support for regex - either in conditions or as an action with capture groups exposed

It would be really good to have support for regular expressions.


This could be surfaced in the UI ideally in both conditions and actions.


A conditional regex would just test whether a string matched against a regex.

An action regex would expose capture groups.

Status: Under Review

This is a great suggestion - we are trying to identify a way to safely run regex in Flow.

Super User

Hi Everyone,

I have written up a way of performing regular expressions in Power Automate for free, without the use of any third party connectors:

How to use Regex in Power Automate 

Be interested to hear how you get on with the solution.


Frequent Visitor

Hi @Paulie78.  Wow, that's a neat addition to the repertoire.  I'd never have thought of that one! 


Neat blog you have too.  That's going on my favourites!


I have a suspicion that an azure function is probably the way to go for the generic case but this is simple and really neat when you know you have Excel around.


And as you so rightly say (in your blog) we need to keep upvoting this and get MS to implement it - or if not at least tell us why it's so difficult!


Thanks again - nice one.

Frequent Visitor


Never thought about that.

Thanks this is very useful.


Yes. @DM2  we must keep this thread,

Regular Visitor

@Paulie78 great suggestion, would still like for MSFT to add this to the product suite though without workarounds.

Kudo Collector

I check Flow ideas about every 6 months. And it's every time totally shocking for me that a basic and so very, very important (and needed) feature like RegEx support is not implemented yet. And not even "in implementation". It's from 2017, top voted most of the time.

It would make so many things for Searching, Filtering, Replacing (!) so much easierRegeEx is a simple and very, very powerful tool. Much better as implemented text search/split, etc. 


What we need?

1. Regex should be possible for conditions and also to search in a string for matching groups and get the matches as output

2. And also of course for text replace, same like in SED.

Having RegEx available for conditions, string search and replaces, will decrease the need of a lot of compose-chains and expression-chains.

Advocate II

Well, its been FOUR years now and I am so fed up with it not being available I've now created a Azure Function App (with HTTP trigger) to do this... If anyone else wants to do this, here's my code.



    public static class RegEx
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = "RegEx")] HttpRequest req,
            ILogger log)
            // Get the request details
            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            RegExRequest request = JsonConvert.DeserializeObject<RegExRequest>(requestBody);

            JObject response = new JObject();

            MatchCollection mc = Regex.Matches(request.Input, request.Pattern);
            if (mc.Count > 0)
                JArray matches = new JArray();
                response["success"] = true;
                foreach (Match m in mc)
                    JObject matchGroups = new JObject();
                    RegExResponseMatch rm = new RegExResponseMatch();
                    for (int g = 1; g < m.Groups.Count; g++)    // Group 0 is the matched string so we ignore it
                        matchGroups[m.Groups[g].Name] = m.Groups[g].Value;
                response["matches"] = matches;
                response["success"] = false;
                response["matches"] = new JArray();

            return new OkObjectResult(response);

    public class RegExRequest
        public string Input { get; set; }
        public string Pattern { get; set; }

    public class RegExResponse
        public bool Success { get; set; }
        public ICollection<RegExResponseMatch> Matches { get; set; }
        public RegExResponse()
            Matches = new List<RegExResponseMatch>();

    public class RegExResponseMatch
        public ICollection<KeyValuePair<string, string>> Groups;
        public RegExResponseMatch()
            Groups = new List<KeyValuePair<string, string>>();



Using Postman, this is the request / response




Kudo Collector

Thanks a lot, this is great!
Even I have programming skills and know Power Automate, I am totally new to azure. Would be great if you can spend some small advices.
- Do we have to make a new subscription to host a function on azure or is it include to have a few functions hosted in office 365 basic plans ("Microsoft 365 Business Standard")? (Or at least in a "Microsoft 365 Business Premium" subscription)
- If not included, do you pay per function call or per cpu time (or whatever)?

- Do you know a easy tutorials how to make your code working as a function in azure which can be called from outside?

New Member

Very necessary tbh and already available in PowerApps. I hope it will be implemented soon.

New Member

I can’t believe that this isn’t implemented yet. It’s the most essential functionality for an automation platform. Sure there’s a workaround, but we wouldn’t have so many issues if this functionality would be possible natively.

Frequent Visitor

Please add this function