diff --git a/dune-project b/dune-project
index 934cd1cf..e326d6a9 100644
--- a/dune-project
+++ b/dune-project
@@ -50,9 +50,9 @@
   (extlib
    (>= 1.7.8))
   (lwt
-   (>= 5.7.0))
+   (and (>= 5.7.0) (< 6.0.0)))
   (lwt_ppx
-   (>= 2.0.0))
+   (and (>= 5.7.0) (< 6.0.0)))
   (ptime
    (>= 1.2.0))
   (ocamldiff
@@ -61,8 +61,7 @@
    (>= 5.1.0))
   (sqlgg
    (>= 20231201))
-  (re2
-   (>= 0.16.0))
+  re
   uri
   (omd
    (< 2))
diff --git a/lib/action.ml b/lib/action.ml
index eb96fd36..5fbec66b 100644
--- a/lib/action.ml
+++ b/lib/action.ml
@@ -31,13 +31,13 @@ let try_process_notification body n =
     Lwt.return_unit
 
 module Action (Github_api : Api.Github) (Slack_api : Api.Slack) (Buildkite_api : Api.Buildkite) = struct
-  let canonical_regex = Re2.create_exn {|\.|\-|\+.*|@.*|}
+  let canonical_regex = Re.Perl.compile_pat {|\.|\-|\+.*|@.*|}
   (* Match email domain, everything after '+', as well as dots and hyphens *)
 
   let username_to_slack_id_tbl = Stringtbl.empty ()
 
   let canonicalize_email_username email =
-    email |> Re2.rewrite_exn ~template:"" canonical_regex |> String.lowercase_ascii
+    email |> Re.replace_string ~all:true canonical_regex ~by:"" |> String.lowercase_ascii
 
   let refresh_username_to_slack_id_tbl ~ctx =
     log#info "updating github to slack username mapping";
diff --git a/lib/api_local.ml b/lib/api_local.ml
index 401927cb..4cc27353 100644
--- a/lib/api_local.ml
+++ b/lib/api_local.ml
@@ -241,9 +241,11 @@ module Buildkite : Api.Buildkite = struct
     match job.log_url with
     | None -> Lwt.return_error "Unable to get job log, job has no log_url field"
     | Some log_url ->
-    match Re2.find_submatches_exn Util.Build.buildkite_api_org_pipeline_build_job_re log_url with
-    | exception exn -> Exn.fail ~exn "failed to parse buildkite build url %s" log_url
-    | [| Some _; Some org; Some pipeline; Some build_nr; Some job_nbr |] ->
+    match Re.exec_opt Util.Build.buildkite_api_org_pipeline_build_job_re log_url with
+    | None -> Exn.fail "failed to parse buildkite build url %s" log_url
+    | Some g ->
+    match Re.Group.(get_opt g 1, get_opt g 2, get_opt g 3, get_opt g 4) with
+    | Some org, Some pipeline, Some build_nr, Some job_nbr ->
       let file =
         clean_forward_slashes
           (sprintf "organizations/%s/pipelines/%s/builds/%s/jobs/%s/logs" org pipeline build_nr job_nbr)
diff --git a/lib/api_remote.ml b/lib/api_remote.ml
index 5e50c2a2..bcb4b3d1 100644
--- a/lib/api_remote.ml
+++ b/lib/api_remote.ml
@@ -107,7 +107,7 @@ module Github : Api.Github = struct
     | "base64" -> begin
       try
         response.content
-        |> Re2.rewrite_exn (Re2.create_exn "\n") ~template:""
+        |> Re.replace_string ~all:true (Re.Perl.compile_pat "\n") ~by:""
         |> decode_string_pad
         |> Config_j.config_of_string
         |> fun res -> Lwt.return @@ Ok res
diff --git a/lib/common.ml b/lib/common.ml
index 5ce87d4f..82ce0346 100644
--- a/lib/common.ml
+++ b/lib/common.ml
@@ -166,9 +166,11 @@ module Stringtbl = struct
   let unwrap = to_list
 end
 
-module Re2 = struct
-  include Re2
+module Regex = struct
+  type t = string * Re.re
 
-  let wrap s = create_exn s
-  let unwrap = Re2.to_string
+  let wrap s = s, Re.Perl.compile_pat s
+  let unwrap (s, _) = s
+
+  let matches (_, re) s = Re.execp re s
 end
diff --git a/lib/dune b/lib/dune
index 39e002a2..ff44b50f 100644
--- a/lib/dune
+++ b/lib/dune
@@ -17,7 +17,7 @@
   omd
   ptime
   ptime.clock
-  re2
+  re
   sexplib0
   sqlgg.sqlite3
   sqlgg.traits
diff --git a/lib/github.ml b/lib/github.ml
index 382c46f6..3cbe725d 100644
--- a/lib/github.ml
+++ b/lib/github.ml
@@ -34,7 +34,8 @@ let event_of_filename filename =
   | [ kind; _; "json" ] -> Some kind
   | _ -> None
 
-let merge_commit_re = Re2.create_exn {|^Merge(?: remote-tracking)? branch '(?:origin/)?(.+)'(?: of [^ ]+)?( into .+)?$|}
+let merge_commit_re =
+  Re.Perl.compile_pat {|^Merge(?: remote-tracking)? branch '(?:origin/)?(.+)'(?: of [^ ]+)?( into .+)?$|}
 
 let is_merge_commit_to_ignore ~(cfg : Config_t.config) ~branch commit =
   match cfg.main_branch_name with
@@ -51,13 +52,15 @@ let is_merge_commit_to_ignore ~(cfg : Config_t.config) ~branch commit =
     *)
     let title = Util.first_line commit.message in
     begin
-      match Re2.find_submatches_exn merge_commit_re title with
-      | [| Some _; Some incoming_branch; receiving_branch |] ->
+      match Re.exec_opt merge_commit_re title with
+      | None -> false
+      | Some g ->
+      match Re.Group.(get_opt g 1, get_opt g 2) with
+      | Some incoming_branch, receiving_branch ->
         let receiving_branch = Option.map (fun s -> Stre.drop_prefix s " into ") receiving_branch in
         (* Should this raise when prefix isn't present? *)
         String.equal branch incoming_branch || Option.map_default (not $ String.equal branch) false receiving_branch
       | _ -> false
-      | exception Re2.Exceptions.Regex_match_failed _ -> false
     end
   | Some _ | None -> false
 
@@ -183,11 +186,11 @@ type gh_resource =
 
 type gh_link = repository * gh_resource
 
-let pr_commit_msg_re = Re2.create_exn {|\(#(\d+)\)|}
-let commit_sha_re = Re2.create_exn {|[a-f0-9]{4,40}|}
+let pr_commit_msg_re = Re.Perl.compile_pat {|\(#(\d+)\)|}
+let commit_sha_re = Re.Perl.compile_pat {|[a-f0-9]{4,40}|}
 let comparer_re = {|([a-zA-Z0-9/:\-_.~\^]+)|}
-let compare_basehead_re = Re2.create_exn (sprintf {|%s([.]{3})%s|} comparer_re comparer_re)
-let gh_org_team_re = Re2.create_exn {|[a-zA-Z0-9\-]+/([a-zA-Z0-9\-]+)|}
+let compare_basehead_re = Re.Perl.compile_pat (sprintf {|%s([.]{3})%s|} comparer_re comparer_re)
+let gh_org_team_re = Re.Perl.compile_pat {|[a-zA-Z0-9\-]+/([a-zA-Z0-9\-]+)|}
 
 (** [gh_link_of_string s] parses a URL string [s] to try to match a supported
     GitHub link type, generating repository endpoints if necessary *)
@@ -238,14 +241,17 @@ let gh_link_of_string url_str =
           Some (repo, Issue (int_of_string n))
         | [ owner; name; "commit"; commit_hash ] | [ owner; name; "pull"; _; "commits"; commit_hash ] ->
           let repo = make_repo ~prefix ~owner ~name in
-          if Re2.matches commit_sha_re commit_hash then Some (repo, Commit commit_hash) else None
+          if Re.execp commit_sha_re commit_hash then Some (repo, Commit commit_hash) else None
         | owner :: name :: "compare" :: base_head | owner :: name :: "pull" :: _ :: "files" :: base_head ->
           let base_head = String.concat "/" base_head in
           let repo = make_repo ~prefix ~owner ~name in
           begin
-            match Re2.find_submatches_exn compare_basehead_re base_head with
-            | [| _; Some base; _; Some merge |] -> Some (repo, Compare (base, merge))
-            | _ | (exception Re2.Exceptions.Regex_match_failed _) -> None
+            match Re.exec_opt compare_basehead_re base_head with
+            | None -> None
+            | Some g ->
+            match Re.Group.(get_opt g 1, get_opt g 3) with
+            | Some base, Some merge -> Some (repo, Compare (base, merge))
+            | _ -> None
           end
         | [] -> None
         | next :: path -> extract_link_type ~prefix:(next :: prefix) path
@@ -256,10 +262,12 @@ let gh_link_of_string url_str =
 let get_project_owners (pr : pull_request) ({ rules } : Config_t.project_owners) =
   Rule.Project_owners.match_rules pr.labels rules
   |> List.partition_map (fun reviewer ->
-         try
-           let team = Re2.find_first_exn ~sub:(`Index 1) gh_org_team_re reviewer in
-           Right team
-         with Re2.Exceptions.Regex_match_failed _ -> Left reviewer)
+         match Re.exec_opt gh_org_team_re reviewer with
+         | None -> Left reviewer
+         | Some g ->
+         match Re.Group.get_opt g 1 with
+         | Some team -> Right team
+         | None -> Left reviewer)
   |> fun (reviewers, team_reviewers) ->
   let already_requested_or_author = pr.user.login :: List.map (fun r -> r.login) pr.requested_reviewers in
   let already_requested_team = List.map (fun r -> r.slug) pr.requested_teams in
diff --git a/lib/rule.atd b/lib/rule.atd
index 08d2ab7a..60ab8234 100644
--- a/lib/rule.atd
+++ b/lib/rule.atd
@@ -1,6 +1,6 @@
 type channel_name = string wrap <ocaml t="Common.Slack_channel.Name.t" wrap="Common.Slack_channel.Name.inject" unwrap="Common.Slack_channel.Name.project">
 
-type regex = string wrap <ocaml module="Common.Re2">
+type regex = string wrap <ocaml module="Common.Regex">
 
 (* Text fields from the GitHub payload that can be used in a condition *)
 type comparable_field = [
diff --git a/lib/rule.ml b/lib/rule.ml
index 3df32391..04ea21ff 100644
--- a/lib/rule.ml
+++ b/lib/rule.ml
@@ -21,7 +21,7 @@ module Status = struct
         | Target_url -> notification.target_url
       in
       let rec match_condition = function
-        | Match { field; re } -> value_of_field field |> Option.map (Re2.matches re) |> Option.default false
+        | Match { field; re } -> value_of_field field |> Option.map (Common.Regex.matches re) |> Option.default false
         | All_of conditions -> List.for_all match_condition conditions
         | One_of conditions -> List.exists match_condition conditions
         | Not condition -> not @@ match_condition condition
diff --git a/lib/slack.ml b/lib/slack.ml
index 12641bad..e63ef1b7 100644
--- a/lib/slack.ml
+++ b/lib/slack.ml
@@ -75,18 +75,18 @@ let make_message ?username ?text ?attachments ?blocks ?thread ?handler ?(reply_b
     },
     handler )
 
-let github_handle_regex = Re2.create_exn {|\B@([[:alnum:]][[:alnum:]-]{1,38})\b|}
 (* Match GH handles in messages - a GitHub handle has at most 39 chars and no underscore *)
+let github_handle_regex = Re.Perl.compile_pat {|\B@([a-zA-Z0-9][a-zA-Z0-9-]{1,38})\b|}
 
 let add_slack_mentions_to_body slack_match_func body =
-  let replace_match m =
-    let gh_handle = Re2.Match.get_exn ~sub:(`Index 0) m in
-    let gh_handle_without_at = Re2.Match.get_exn ~sub:(`Index 1) m in
+  let replace_match g =
+    let gh_handle = Re.Group.get g 0 in
+    let gh_handle_without_at = Re.Group.get g 1 in
     match slack_match_func gh_handle_without_at with
     | None -> gh_handle
     | Some user_id -> sprintf "<@%s>" (Slack_user_id.project user_id)
   in
-  Re2.replace_exn github_handle_regex body ~f:replace_match
+  Re.replace ~all:true github_handle_regex ~f:replace_match body
 
 let format_attachments ~slack_match_func ~footer ~body =
   let format_mention_in_markdown (md : unfurl) =
@@ -264,16 +264,16 @@ let git_short_sha_hash hash = String.sub hash 0 8
 let pp_commit_common url id message author =
   let title = escape_mrkdwn @@ first_line message in
   (* check if the title contains a PR number and enrich with the PR link if so *)
-  match Re2.matches Github.pr_commit_msg_re title with
+  match Re.execp Github.pr_commit_msg_re title with
   | false -> sprintf "`<%s|%s>` %s - %s" url (git_short_sha_hash id) title author
   | true ->
-    let f m =
-      let pr_num = Re2.Match.get_exn ~sub:(`Index 1) m in
+    let f g =
+      let pr_num = Re.Group.get g 1 in
       match Github.gh_link_of_string url with
       | Some ((r, _) : repository * Github.gh_resource) -> sprintf "(<%s/pull/%s|#%s>)" r.url pr_num pr_num
       | None -> sprintf "(#%s)" pr_num
     in
-    let title' = Re2.replace_exn Github.pr_commit_msg_re title ~f in
+    let title' = Re.replace ~all:true Github.pr_commit_msg_re ~f title in
     sprintf "`<%s|%s>` %s - %s" url (git_short_sha_hash id) title' author
 
 let pp_commit ({ url; id; message; author; _ } : commit) = pp_commit_common url id message (escape_mrkdwn @@ author.name)
@@ -335,7 +335,7 @@ let generate_push_notification notification channel =
     in
     make_message ~username ~channel ~text:(String.concat "\n" lines) ()
 
-let buildkite_description_re = Re2.create_exn {|^Build #(\d+)(.*)|}
+let buildkite_description_re = Re.Perl.compile_pat {|^Build #(\d+)(.*)|}
 
 let generate_status_notification ~(job_log : (string * string) list) ~(cfg : Config_t.config) (n : status_notification)
   channel =
@@ -353,13 +353,14 @@ let generate_status_notification ~(job_log : (string * string) list) ~(cfg : Con
     | Some _ when not is_buildkite -> desc
     | Some target_url ->
     (* Specific to buildkite *)
-    match Re2.find_submatches_exn buildkite_description_re desc with
-    | [| Some _; Some build_nr; Some rest |] ->
+    match Re.exec_opt buildkite_description_re desc with
+    | None -> desc
+    | Some g ->
+    match Re.Group.get_opt g 1, Re.Group.get_opt g 2 with
+    | Some build_nr, Some rest ->
       (* We use a zero-with space \u{200B} to prevent slack from interpreting #XXXXXX as a color *)
       sprintf "Build <%s|#\u{200B}%s>%s" target_url build_nr rest
-    | _ | (exception _) ->
-      (* we either match on the first case or get an exception *)
-      desc
+    | _ -> desc
   in
   let author_mention =
     (* If the author's email is not associated with a github account the author will be missing.
diff --git a/lib/util.ml b/lib/util.ml
index 48871603..9f0532a5 100644
--- a/lib/util.ml
+++ b/lib/util.ml
@@ -44,40 +44,39 @@ module Build = struct
     pipeline_name : string;
   }
 
-  let buildkite_is_failed_re = Re2.create_exn {|^Build #\d+ failed|}
-  let buildkite_is_failing_re = Re2.create_exn {|^Build #(\d+) is failing|}
-  let buildkite_is_canceled_re = Re2.create_exn {|^Build #\d+ canceled by .+|}
-  let buildkite_is_success_re = Re2.create_exn {|^Build #\d+ passed|}
+  let buildkite_is_failed_re = Re.Perl.compile_pat {|^Build #\d+ failed|}
+  let buildkite_is_failing_re = Re.Perl.compile_pat {|^Build #(\d+) is failing|}
+  let buildkite_is_canceled_re = Re.Perl.compile_pat {|^Build #\d+ canceled by .+|}
+  let buildkite_is_success_re = Re.Perl.compile_pat {|^Build #\d+ passed|}
 
   let buildkite_org_pipeline_build_re =
     (* buildkite.com/<org_name>/<pipeline_name>/builds/<build_number> *)
-    Re2.create_exn {|buildkite.com/([\w_-]+)/([\w_-]+)/builds/(\d+)|}
+    Re.Perl.compile_pat {|buildkite.com/([\w_-]+)/([\w_-]+)/builds/(\d+)|}
 
   let buildkite_api_org_pipeline_build_job_re =
     (* https://api.buildkite.com/v2/organizations/<org_name>/pipelines/<pipeline_name>/builds/<build_number>/jobs/<job_number>/log *)
-    Re2.create_exn
+    Re.Perl.compile_pat
       {|https://api.buildkite.com/v2/organizations/([\w_-]+)/pipelines/([\w_-]+)/builds/(\d+)/jobs/([\d\w_-]+)/log|}
 
   let buildkite_is_step_re =
     (* Checks if a pipeline or build step, by looking into the buildkite context
        buildkite/<pipeline_name>/<step_name>(/<substep_name>?) *)
-    Re2.create_exn {|buildkite/[\w_-]+/([\w_-]+(/[\w_-]+)*)|}
+    Re.Perl.compile_pat {|buildkite/[\w_-]+/([\w_-]+(/[\w_-]+)*)|}
 
   let buildkite_pipeline_name_re =
     (* Gets the pipeline name from the buildkite context *)
-    Re2.create_exn {|buildkite/([\w_-]+)|}
+    Re.Perl.compile_pat {|buildkite/([\w_-]+)|}
 
-  let is_pipeline_step context = Re2.matches buildkite_is_step_re context
+  let is_pipeline_step context = Re.execp buildkite_is_step_re context
 
   (** For now we only care about buildkite pipelines and steps. Other CI systems are not supported yet. *)
   let parse_context ~context =
     match Stre.starts_with context "buildkite/" with
     | false -> None
     | true ->
-    try
-      let pipeline_name = Re2.find_first_exn ~sub:(`Index 1) buildkite_pipeline_name_re context in
-      Some { is_pipeline_step = is_pipeline_step context; pipeline_name }
-    with _ -> None
+    match Re.exec_opt buildkite_pipeline_name_re context with
+    | None -> None
+    | Some g -> Some { is_pipeline_step = is_pipeline_step context; pipeline_name = Re.Group.get g 1 }
 
   let parse_context_exn ~context =
     match parse_context ~context with
@@ -86,13 +85,13 @@ module Build = struct
 
   let buildkite_build_number_re =
     (* buildkite.com/<org_name>/<pipeline_name>/builds/<build_number> *)
-    Re2.create_exn {|buildkite.com/[\w_-]+/[\w_-]+/builds/(\d+)|}
+    Re.Perl.compile_pat {|buildkite.com/[\w_-]+/[\w_-]+/builds/(\d+)|}
 
   (** For now we only care about buildkite pipelines and steps. Other CI systems are not supported yet. *)
   let get_build_number_exn ~build_url =
-    match Re2.find_first_exn ~sub:(`Index 1) buildkite_build_number_re build_url with
-    | build_number -> int_of_string build_number
-    | exception _ -> util_error "failed to get build number from url"
+    match Re.exec_opt buildkite_build_number_re build_url with
+    | Some g -> int_of_string (Re.Group.get g 1)
+    | None -> util_error "failed to get build number from url"
 
   let get_build_url (n : Github_t.status_notification) =
     match n.target_url with
@@ -100,21 +99,23 @@ module Build = struct
     | Some build_url -> Ok build_url
 
   let get_org_pipeline_build' build_url =
-    match Re2.find_submatches_exn buildkite_org_pipeline_build_re build_url with
-    | exception _ -> util_error "failed to parse Buildkite build url: %s" build_url
-    | [| Some _; Some org; Some pipeline; Some build_nr |] -> org, pipeline, build_nr
+    match Re.exec_opt buildkite_org_pipeline_build_re build_url with
+    | None -> util_error "failed to parse Buildkite build url: %s" build_url
+    | Some g ->
+    match Re.Group.get_opt g 1, Re.Group.get_opt g 2, Re.Group.get_opt g 3 with
+    | Some org, Some pipeline, Some build_nr -> org, pipeline, build_nr
     | _ -> util_error "failed to get the build details from the notification. Is this a Buildkite notification?"
 
   let get_org_pipeline_build (n : Github_t.status_notification) = Result.(map get_org_pipeline_build' (get_build_url n))
 
   let is_failed_build (n : Github_t.status_notification) =
-    n.state = Failure && Re2.matches buildkite_is_failed_re (Option.default "" n.description)
+    n.state = Failure && Re.execp buildkite_is_failed_re (Option.default "" n.description)
 
   let is_failing_build (n : Github_t.status_notification) =
-    n.state = Failure && Re2.matches buildkite_is_failing_re (Option.default "" n.description)
+    n.state = Failure && Re.execp buildkite_is_failing_re (Option.default "" n.description)
 
   let is_canceled_build (n : Github_t.status_notification) =
-    n.state = Failure && Re2.matches buildkite_is_canceled_re (Option.default "" n.description)
+    n.state = Failure && Re.execp buildkite_is_canceled_re (Option.default "" n.description)
 
   let is_main_branch (cfg : Config_t.config) (n : Github_t.status_notification) =
     match cfg.main_branch_name with
@@ -255,15 +256,15 @@ module Webhook = struct
 
   let git_ssh_re =
     (* matches git ssh clone links *)
-    Re2.create_exn {|^git@([A-Za-z0-9.-]+):([A-Za-z0-9._-]+)\/([A-Za-z0-9._-]+)\.git$|}
+    Re.Perl.compile_pat {|^git@([A-Za-z0-9.-]+):([A-Za-z0-9._-]+)\/([A-Za-z0-9._-]+)\.git$|}
 
   let git_ssh_to_repo url =
-    match Re2.find_submatches_exn git_ssh_re url with
-    | exception exn -> util_error ~exn "failed to parse git ssh link %s" url
-    | [| Some _; Some "github.com"; Some user; Some repo |] -> Github { url = "github.com"; user; repo }
-    | [| Some _; Some url; Some user; Some repo |] ->
-      (* GHE links *)
-      GHE { url; user; repo }
+    match Re.exec_opt git_ssh_re url with
+    | None -> util_error "failed to parse git ssh link %s" url
+    | Some g ->
+    match Re.Group.get_opt g 1, Re.Group.get_opt g 2, Re.Group.get_opt g 3 with
+    | Some host, Some user, Some repo when host = "github.com" -> Github { url = "github.com"; user; repo }
+    | Some url, Some user, Some repo -> GHE { url; user; repo }
     | _ -> util_error "failed to get repo details from the ssh link."
 
   let git_ssh_to_api_url ?(resource = "") url =
diff --git a/monorobot.opam b/monorobot.opam
index 8010a9d5..de51543a 100644
--- a/monorobot.opam
+++ b/monorobot.opam
@@ -21,13 +21,13 @@ depends: [
   "digestif" {>= "1.2.0"}
   "devkit" {>= "1.20240429"}
   "extlib" {>= "1.7.8"}
-  "lwt" {>= "5.7.0"}
-  "lwt_ppx" {>= "2.0.0"}
+  "lwt" {>= "5.7.0" & < "6.0.0"}
+  "lwt_ppx" {>= "5.7.0" & < "6.0.0"}
   "ptime" {>= "1.2.0"}
   "ocamldiff" {>= "1.2"}
   "sqlite3" {>= "5.1.0"}
   "sqlgg" {>= "20231201"}
-  "re2" {>= "0.16.0"}
+  "re"
   "uri"
   "omd" {< "2"}
   "yojson"