diff --git a/src/main/clj/org/domaindrivenarchitecture/activity_pub_poc/core.clj b/src/main/clj/org/domaindrivenarchitecture/activity_pub_poc/core.clj
index 3ea82a0..cb4bf74 100644
--- a/src/main/clj/org/domaindrivenarchitecture/activity_pub_poc/core.clj
+++ b/src/main/clj/org/domaindrivenarchitecture/activity_pub_poc/core.clj
@@ -7,7 +7,8 @@
             [clojure.inspector :as ins]
             [hato.client :as hato]
             [clojure.string :as st]
-            [clojure.walk :as walk]))
+            [clojure.walk :as walk]
+            [clojure.string :as str]))
 
 (def team-url "https://social.meissa-gmbh.de/users/team")
 (def like-url "https://www.w3.org/ns/activitystreams#Like")
@@ -20,9 +21,22 @@
 
 (def team (ap/GET team-url))
 
-
 (def parsed-rdf-syntax (parse (slurp cm/activitystreams-ttl)))
 
+(defn type-string? [input]
+  (re-matches #"[A-Z]" (str (first input))))
+
+(defn uri-vector? [input]
+  (and (every? #(uri? %) input)
+       (vector? input)))
+
+; Specs for a like
+(s/def ::context uri?)
+(s/def ::type type-string?)
+(s/def ::id uri?)
+(s/def ::to uri-vector?)
+(s/def ::actor uri?)
+(s/def ::object uri?)
 
 ; ToDo
 ; Prädikat das langString parsen/validieren kann, evtl auch für xsd:string