diff --git a/src/Hash2Pub/PostService.hs b/src/Hash2Pub/PostService.hs
index 99a9efb..797a9e6 100644
--- a/src/Hash2Pub/PostService.hs
+++ b/src/Hash2Pub/PostService.hs
@@ -19,6 +19,7 @@ import           Control.Exception             (Exception (..), try)
 import           Control.Monad                 (foldM, forM, forM_, forever)
 import           Control.Monad.IO.Class        (liftIO)
 import           Control.Monad.STM
+import           Data.Bifunctor
 import qualified Data.ByteString.Lazy.UTF8     as BSUL
 import qualified Data.ByteString.UTF8          as BSU
 import qualified Data.HashMap.Strict           as HMap
@@ -409,6 +410,20 @@ clientUnsubscribeFrom serv tag = do
           lookupResponse
 
 
+-- | publish a new post to the inbox of a specified relay instance. This
+-- instance will then be the originating instance of the post and will forward
+-- the post to the responsible relays.
+-- As the initial publishing isn't done by a specific relay (but *to* a specific relay
+-- instead), the function does *not* take a PostService as argument.
+clientPublishPost :: HTTP.Manager   -- for better performance, a shared HTTP manager has to be provided
+                  -> String         -- hostname
+                  -> Int            -- port
+                  -> PostContent    -- post content
+                  -> IO (Either String ())  -- error or success
+clientPublishPost httpman hostname port postC = do
+    resp <- runClientM (postInboxClient postC) (mkClientEnv httpman (BaseUrl Http hostname port ""))
+    pure . bimap show (const ()) $ resp
+
 -- currently this is unused code
 getClients :: String -> Int -> HTTP.Manager -> Client IO PostServiceAPI
 getClients hostname' port' httpMan = hoistClient clientAPI