diff --git a/.gitignore b/.gitignore
index 55ab5df..a87dbc4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
 config.edn
 package-lock.json
+/.shadow-cljs
 /node_modules
+/target
diff --git a/README.md b/README.md
index c5a1d9f..10dea30 100644
--- a/README.md
+++ b/README.md
@@ -80,8 +80,8 @@ with later timestamps to avoid duplicate posts. On the first run the timestamp w
             ;; optional keyword filter regexes
             ;; any posts not matching the regexes will be filtered out
             :keyword-filters [".*clojure.*"]
-	    ;; Replace Twitter links by Nitter
-	    :nitter-urls? false}}
+            ;; Replace Twitter links by Nitter
+            :nitter-urls? false}}
 ```
 
 * the bot looks for `config.edn` at its relative path by default, an alternative location can be specified either using the `MASTODON_BOT_CONFIG` environment variable or passing the path to config as an argument
diff --git a/mastodon_bot/core.cljs b/mastodon_bot/core.cljs
deleted file mode 100755
index ba0d749..0000000
--- a/mastodon_bot/core.cljs
+++ /dev/null
@@ -1,243 +0,0 @@
-#!/usr/bin/env lumo
-
-(ns mastodon-bot.core
-  (:require
-   [cljs.core :refer [*command-line-args*]]
-   [cljs.reader :as edn]
-   [clojure.set :refer [rename-keys]]
-   [clojure.string :as string]
-   ["deasync" :as deasync]
-   ["request" :as request]
-   ["fs" :as fs]
-   ["mastodon-api" :as mastodon]
-   ["rss-parser" :as rss]
-   ["tumblr" :as tumblr]
-   ["twitter" :as twitter]))
-
-(defn exit-with-error [error]
-  (js/console.error error)
-  (js/process.exit 1))
-
-(defn find-config []
-  (let [config (or (first *command-line-args*)
-                   (-> js/process .-env .-MASTODON_BOT_CONFIG)
-                   "config.edn")]
-    (if (fs/existsSync config)
-      config
-      (exit-with-error (str "failed to read config: " config)))))
-
-(def config (-> (find-config) (fs/readFileSync #js {:encoding "UTF-8"}) edn/read-string))
-
-(def mastodon-config (:mastodon config))
-
-(def mastodon-client (or (some-> mastodon-config clj->js mastodon.)
-                         (exit-with-error "missing Mastodon client configuration!")))
-
-(def content-filter-regexes (mapv re-pattern (:content-filters mastodon-config)))
-
-(def keyword-filter-regexes (mapv re-pattern (:keyword-filters mastodon-config)))
-
-(def append-screen-name? (boolean (:append-screen-name? mastodon-config)))
-
-(def max-post-length (:max-post-length mastodon-config))
-
-(defn blocked-content? [text]
- (boolean
-   (or (some #(re-find % text) content-filter-regexes)
-       (when (not-empty keyword-filter-regexes)
-             (empty? (some #(re-find % text) keyword-filter-regexes))))))
-
-(defn js->edn [data]
-  (js->clj data :keywordize-keys true))
-
-(defn trim-text [text]
-  (cond
-
-    (nil? max-post-length)
-    text
-
-    (> (count text) max-post-length)
-    (reduce
-     (fn [text word]
-       (if (> (+ (count text) (count word)) (- max-post-length 3))
-         (reduced (str text "..."))
-         (str text " " word)))
-     ""
-     (string/split text #" "))
-
-    :else text))
-
-(defn delete-status [status]
-  (.delete mastodon-client (str "statuses/" status) #js {}))
-
-(defn resolve-url [[uri]]
-  (try
-    (or
-      (some-> ((deasync request)
-               #js {:method "GET"
-                    :uri (if (string/starts-with? uri "https://") uri (str "https://" uri))
-                    :followRedirect false})
-              (.-headers)
-              (.-location)
-              (string/replace "?mbid=social_twitter" ""))
-      uri)
-    (catch js/Error _ uri)))
-
-(def shortened-url-pattern #"(https?://)?(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,}))\.?)(?::\d{2,5})?(?:[/?#]\S*)?")
-
-(defn resolve-urls [text]
-  (cond-> text
-    (:resolve-urls? mastodon-config)
-    (string/replace shortened-url-pattern resolve-url)
-    (:nitter-urls? mastodon-config)
-    (string/replace #"https://twitter.com" "https://nitter.net")))
-
-(defn perform-replacements [text]
-  (reduce-kv string/replace text (:replacements mastodon-config)))
-
-(defn set-signature [text]
-  (if-let [signature (:signature mastodon-config )]
-    (str text "\n" signature)
-    text))
-
-(defn post-status
-  ([status-text]
-   (post-status status-text nil))
-  ([status-text media-ids]
-   (let [{:keys [sensitive? signature visibility]} mastodon-config]
-     (.post mastodon-client "statuses"
-          (clj->js (merge {:status (-> status-text resolve-urls perform-replacements set-signature)}
-                          (when media-ids {:media_ids media-ids})
-                          (when sensitive? {:sensitive sensitive?})
-                          (when visibility {:visibility visibility})))))))
-
-(defn post-image [image-stream description callback]
-  (-> (.post mastodon-client "media" #js {:file image-stream :description description})
-      (.then #(-> % .-data .-id callback))))
-
-(defn post-status-with-images
-  ([status-text urls]
-   (post-status-with-images status-text urls []))
-  ([status-text [url & urls] ids]
-   (if url
-     (-> request
-         (.get url)
-         (.on "response"
-           (fn [image-stream]
-             (post-image image-stream status-text #(post-status-with-images status-text urls (conj ids %))))))
-     (post-status status-text (not-empty ids)))))
-
-(defn get-mastodon-timeline [callback]
-  (.then (.get mastodon-client (str "accounts/" (:account-id mastodon-config)"/statuses") #js {})
-         #(let [response (-> % .-data js->edn)]
-            (if-let [error (:error response)]
-              (exit-with-error error)
-              (callback response)))))
-
-(defn post-items [last-post-time items]
-  (doseq [{:keys [text media-links]} (->> items
-                                          (remove #(blocked-content? (:text %)))
-                                          (filter #(> (:created-at %) last-post-time)))]
-    (if media-links
-      (post-status-with-images text media-links)
-      (when-not (:media-only? mastodon-config)
-        (post-status text)))))
-
-(defn in [needle haystack]
-  (some (partial = needle) haystack))
-
-; If the text ends in a link to the media (which is uploaded anyway),
-; chop it off instead of including the link in the toot
-(defn chop-tail-media-url [text media]
-  (string/replace text #" (\S+)$" #(if (in (%1 1) (map :url media)) "" (%1 0))))
-
-(defn parse-tweet [{created-at            :created_at
-                    text                  :full_text
-                    {:keys [media]}       :extended_entities
-                    {:keys [screen_name]} :user :as tweet}]
-  {:created-at (js/Date. created-at)
-   :text (trim-text (str (chop-tail-media-url text media) (if append-screen-name? (str "\n - " screen_name) "")))
-   :media-links (keep #(when (= (:type %) "photo") (:media_url_https %)) media)})
-
-(defmulti parse-tumblr-post :type)
-
-(defmethod parse-tumblr-post "text" [{:keys [body date short_url]}]
-  {:created-at (js/Date. date)
-   :text (str (trim-text body) "\n\n" short_url)})
-
-(defmethod parse-tumblr-post "photo" [{:keys [caption date photos short_url] :as post}]
-  {:created-at (js/Date. date)
-   :text (string/join "\n" [(string/replace caption #"<[^>]*>" "") short_url])
-   :media-links (mapv #(-> % :original_size :url) photos)})
-
-(defmethod parse-tumblr-post :default [post])
-
-(defn post-tumblrs [last-post-time]
-  (fn [err response]
-    (->> response
-         js->edn
-         :posts
-         (mapv parse-tumblr-post)
-         (post-items last-post-time))))
-
-(defn post-tweets [last-post-time]
-  (fn [error tweets response]
-    (if error
-      (exit-with-error error)
-      (->> (js->edn tweets)
-           (map parse-tweet)
-           (post-items last-post-time)))))
-
-(defn strip-utm [news-link]
-  (first (string/split news-link #"\?utm")))
-
-(defn parse-feed [last-post-time parser [title url]]
-  (-> (.parseURL parser url)
-      (.then #(post-items
-               last-post-time
-               (for [{:keys [title isoDate pubDate content link]} (-> % js->edn :items)]
-                 {:created-at (js/Date. (or isoDate pubDate))
-                  :text (str (trim-text title) "\n\n" (strip-utm link))})))))
-
-(defn twitter-client [access-keys]
-  (try
-    (twitter. (clj->js access-keys))
-    (catch js/Error e
-      (exit-with-error
-       (str "failed to connect to Twitter: " (.-message e))))))
-
-(defn tumblr-client [access-keys account]
-  (try
-    (tumblr/Blog. account (clj->js access-keys))
-    (catch js/Error e
-      (exit-with-error
-       (str "failed to connect to Tumblr account " account ": " (.-message e))))))
-
-(defn -main []
-  (get-mastodon-timeline
-   (fn [timeline]
-     (let [last-post-time (-> timeline first :created_at (js/Date.))]
-     ;;post from Twitter
-       (when-let [twitter-config (:twitter config)]
-         (let [{:keys [access-keys accounts include-replies? include-rts?]} twitter-config
-               client (twitter-client access-keys)]
-           (doseq [account accounts]
-             (.get client
-                   "statuses/user_timeline"
-                   #js {:screen_name account
-                        :tweet_mode "extended"
-                        :include_rts (boolean include-rts?)
-                        :exclude_replies (not (boolean include-replies?))}
-                   (post-tweets last-post-time)))))
-     ;;post from Tumblr
-       (when-let [{:keys [access-keys accounts limit]} (:tumblr config)]
-         (doseq [account accounts]
-           (let [client (tumblr-client access-keys account)]
-             (.posts client #js {:limit (or limit 5)} (post-tumblrs last-post-time)))))
-     ;;post from RSS
-       (when-let [feeds (some-> config :rss)]
-         (let [parser (rss.)]
-           (doseq [feed feeds]
-             (parse-feed last-post-time parser feed))))))))
-
-(set! *main-cli-fn* -main)
diff --git a/shadow-cljs.edn b/shadow-cljs.edn
index d666e71..337ec72 100644
--- a/shadow-cljs.edn
+++ b/shadow-cljs.edn
@@ -1,6 +1,12 @@
-{:source-paths ["mastodon_bot"]
- :dependencies []
- :builds       {:app {:target    :node-script
+{:source-paths ["src/main"
+                "src/test"]
+ :dependencies [[orchestra "2018.12.06-2"]]
+ :builds       {:dev {:target       :node-library
+                      :output-to    "target/lib-mastodon-bot.js"
+                      :exports   {:infra mastodon-bot.infra/js->edn}
+                      :repl-pprint  true
+                      }
+                :app {:target    :node-script
                       :output-to "target/mastodon-bot.js"
                       :main      mastodon-bot.core/main
                       :compiler-options {:optimizations :simple}}}}
diff --git a/src/main/mastodon_bot/core.cljs b/src/main/mastodon_bot/core.cljs
new file mode 100755
index 0000000..3a78cbc
--- /dev/null
+++ b/src/main/mastodon_bot/core.cljs
@@ -0,0 +1,154 @@
+#!/usr/bin/env lumo
+
+(ns mastodon-bot.core
+  (:require
+   [clojure.spec.alpha :as s]
+   [clojure.spec.test.alpha :as st]
+   [orchestra.core :refer-macros [defn-spec]]
+   [cljs.core :refer [*command-line-args*]]
+   [clojure.string :as string]
+   ["rss-parser" :as rss]
+   ["tumblr" :as tumblr]
+   ["twitter" :as twitter]
+   [mastodon-bot.infra :as infra]
+   [mastodon-bot.mastodon-api :as masto]))
+
+(s/def ::mastodon-config masto/mastodon-config?)
+(s/def ::twitter map?)
+(s/def ::tumblr map?)
+(s/def ::rss map?)
+
+(def config? (s/keys :req-un [::mastodon-config]
+                     :opt-un [::twitter ::tumblr ::rss]))
+
+(defn-spec mastodon-config ::mastodon-config
+  [config config?]
+  (:mastodon-config config))
+
+(def config (infra/load-config))
+
+(defn trim-text [text]
+  (let [max-post-length (masto/max-post-length (mastodon-config config))]
+    (cond
+
+      (nil? max-post-length)
+      text
+
+      (> (count text) max-post-length)
+      (reduce
+       (fn [text word]
+         (if (> (+ (count text) (count word)) (- max-post-length 3))
+           (reduced (str text "..."))
+           (str text " " word)))
+       ""
+       (string/split text #" "))
+
+      :else text)))
+
+(defn in [needle haystack]
+  (some (partial = needle) haystack))
+
+; If the text ends in a link to the media (which is uploaded anyway),
+; chop it off instead of including the link in the toot
+(defn chop-tail-media-url [text media]
+  (string/replace text #" (\S+)$" #(if (in (%1 1) (map :url media)) "" (%1 0))))
+
+(defn parse-tweet [{created-at            :created_at
+                    text                  :full_text
+                    {:keys [media]}       :extended_entities
+                    {:keys [screen_name]} :user :as tweet}]
+  {:created-at (js/Date. created-at)
+   :text (trim-text (str (chop-tail-media-url text media) 
+                         (if (masto/append-screen-name? (mastodon-config config)) 
+                           (str "\n - " screen_name) "")))
+   :media-links (keep #(when (= (:type %) "photo") (:media_url_https %)) media)})
+
+(defmulti parse-tumblr-post :type)
+
+(defmethod parse-tumblr-post "text" [{:keys [body date short_url]}]
+  {:created-at (js/Date. date)
+   :text (str (trim-text body) "\n\n" short_url)})
+
+(defmethod parse-tumblr-post "photo" [{:keys [caption date photos short_url] :as post}]
+  {:created-at (js/Date. date)
+   :text (string/join "\n" [(string/replace caption #"<[^>]*>" "") short_url])
+   :media-links (mapv #(-> % :original_size :url) photos)})
+
+(defmethod parse-tumblr-post :default [post])
+
+(defn post-tumblrs [last-post-time]
+  (fn [err response]
+    (->> response
+         infra/js->edn
+         :posts
+         (mapv parse-tumblr-post)
+         (masto/post-items 
+          (mastodon-config config)
+          last-post-time))))
+
+(defn post-tweets [last-post-time]
+  (fn [error tweets response]
+    (if error
+      (infra/exit-with-error error)
+      (->> (infra/js->edn tweets)
+           (map parse-tweet)
+           (masto/post-items 
+            (mastodon-config config)
+            last-post-time)))))
+
+(defn strip-utm [news-link]
+  (first (string/split news-link #"\?utm")))
+
+(defn parse-feed [last-post-time parser [title url]]
+  (-> (.parseURL parser url)
+      (.then #(masto/post-items
+               (mastodon-config config)
+               last-post-time
+               (for [{:keys [title isoDate pubDate content link]} (-> % infra/js->edn :items)]
+                 {:created-at (js/Date. (or isoDate pubDate))
+                  :text (str (trim-text title) "\n\n" (strip-utm link))})))))
+
+(defn twitter-client [access-keys]
+  (try
+    (twitter. (clj->js access-keys))
+    (catch js/Error e
+      (infra/exit-with-error
+       (str "failed to connect to Twitter: " (.-message e))))))
+
+(defn tumblr-client [access-keys account]
+  (try
+    (tumblr/Blog. account (clj->js access-keys))
+    (catch js/Error e
+      (infra/exit-with-error
+       (str "failed to connect to Tumblr account " account ": " (.-message e))))))
+
+(defn -main []
+  (masto/get-mastodon-timeline
+   (mastodon-config config)
+   (fn [timeline]
+     (let [last-post-time (-> timeline first :created_at (js/Date.))]
+     ;;post from Twitter
+       (when-let [twitter-config (:twitter config)]
+         (let [{:keys [access-keys accounts include-replies? include-rts?]} twitter-config
+               client (twitter-client access-keys)]
+           (doseq [account accounts]
+             (.get client
+                   "statuses/user_timeline"
+                   #js {:screen_name account
+                        :tweet_mode "extended"
+                        :include_rts (boolean include-rts?)
+                        :exclude_replies (not (boolean include-replies?))}
+                   (post-tweets last-post-time)))))
+     ;;post from Tumblr
+       (when-let [{:keys [access-keys accounts limit]} (:tumblr config)]
+         (doseq [account accounts]
+           (let [client (tumblr-client access-keys account)]
+             (.posts client #js {:limit (or limit 5)} (post-tumblrs last-post-time)))))
+     ;;post from RSS
+       (when-let [feeds (some-> config :rss)]
+         (let [parser (rss.)]
+           (doseq [feed feeds]
+             (parse-feed last-post-time parser feed))))))))
+
+(set! *main-cli-fn* -main)
+(st/instrument 'mastodon-config)
diff --git a/src/main/mastodon_bot/infra.cljs b/src/main/mastodon_bot/infra.cljs
new file mode 100755
index 0000000..a2f1bcf
--- /dev/null
+++ b/src/main/mastodon_bot/infra.cljs
@@ -0,0 +1,22 @@
+(ns mastodon-bot.infra
+  (:require
+   [cljs.reader :as edn]
+   ["fs" :as fs]))
+
+(defn js->edn [data]
+  (js->clj data :keywordize-keys true))
+
+(defn exit-with-error [error]
+  (js/console.error error)
+  (js/process.exit 1))
+
+(defn find-config []
+  (let [config (or (first *command-line-args*)
+                   (-> js/process .-env .-MASTODON_BOT_CONFIG)
+                   "config.edn")]
+    (if (fs/existsSync config)
+      config
+      (exit-with-error (str "failed to read config: " config)))))
+
+(defn load-config []
+  (-> (find-config) (fs/readFileSync #js {:encoding "UTF-8"}) edn/read-string))
\ No newline at end of file
diff --git a/src/main/mastodon_bot/mastodon_api.cljs b/src/main/mastodon_bot/mastodon_api.cljs
new file mode 100755
index 0000000..0d05c65
--- /dev/null
+++ b/src/main/mastodon_bot/mastodon_api.cljs
@@ -0,0 +1,171 @@
+(ns mastodon-bot.mastodon-api
+  (:require
+   [clojure.spec.alpha :as s]
+   [clojure.spec.test.alpha :as st]
+   [orchestra.core :refer-macros [defn-spec]]
+   [clojure.string :as string]
+   [mastodon-bot.infra :as infra]
+   ["deasync" :as deasync]
+   ["request" :as request]
+   ["mastodon-api" :as mastodon]))
+
+; Todo: think about how namespaced keywords & clj->js can play nicely together
+(s/def ::access_token string?)
+(s/def ::api_url string?)
+(s/def ::account-id string?)
+(s/def ::content-filter string?)
+(s/def ::keyword-filter string?)
+(s/def ::append-screen-name? boolean?)
+(s/def ::signature string?)
+(s/def ::sensitive? boolean?)
+(s/def ::resolve-urls? boolean?)
+(s/def ::nitter-urls? boolean?)
+(s/def ::visibility string?)
+(s/def ::replacements string?)
+(s/def ::max-post-length (fn [n] (and
+                                 (int? n)
+                                 (<= n 500)
+                                 (> n 0))))
+
+(s/def ::content-filters (s/* ::content-filter))
+(s/def ::keyword-filters (s/* ::keyword-filter))
+(s/def ::mastodon-js-config (s/keys :req-un [::access_token ::api_url]))
+(s/def ::mastodon-clj-config (s/keys :req-un [::account-id ::content-filters ::keyword-filters
+                                              ::max-post-length ::signature ::visibility
+                                              ::append-screen-name? ::sensitive? ::resolve-urls?
+                                              ::nitter-urls? ::replacements]))
+(def mastodon-config? (s/merge ::mastodon-js-config ::mastodon-clj-config))
+
+(defn-spec content-filter-regexes ::content-filters
+  [mastodon-config mastodon-config?]
+  (mapv re-pattern (:content-filters mastodon-config)))
+
+(defn-spec keyword-filter-regexes ::keyword-filters
+  [mastodon-config mastodon-config?]
+  (mapv re-pattern (:keyword-filters mastodon-config)))
+
+(defn-spec append-screen-name? ::append-screen-name?
+  [mastodon-config mastodon-config?]
+  (boolean (:append-screen-name? mastodon-config)))
+
+(defn-spec max-post-length ::max-post-length
+  [mastodon-config mastodon-config?]
+  (:max-post-length mastodon-config))
+
+(defn-spec perform-replacements string?
+  [mastodon-config mastodon-config?
+   text string?]
+  (reduce-kv string/replace text (:replacements mastodon-config)))
+
+(defn-spec mastodon-client any?
+  [mastodon-config mastodon-config?]
+  (or (some-> mastodon-config clj->js mastodon.)
+      (infra/exit-with-error "missing Mastodon client configuration!")))
+
+(defn-spec blocked-content? boolean?
+  [mastodon-config mastodon-config?
+   text string?]
+ (boolean
+   (or (some #(re-find % text) (content-filter-regexes mastodon-config))
+       (when (not-empty (keyword-filter-regexes mastodon-config))
+             (empty? (some #(re-find % text) (keyword-filter-regexes mastodon-config)))))))
+
+(defn-spec delete-status any?
+  [mastodon-config mastodon-config?
+   status-id string?]
+  (.delete (mastodon-client mastodon-config) (str "statuses/" status-id) #js {}))
+
+(defn resolve-url [[uri]]
+  (try
+    (or
+     (some-> ((deasync request)
+              #js {:method "GET"
+                   :uri (if (string/starts-with? uri "https://") uri (str "https://" uri))
+                   :followRedirect false})
+             (.-headers)
+             (.-location)
+             (string/replace "?mbid=social_twitter" ""))
+     uri)
+    (catch js/Error _ uri)))
+
+(def shortened-url-pattern #"(https?://)?(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,}))\.?)(?::\d{2,5})?(?:[/?#]\S*)?")
+
+(defn-spec resolve-urls string?
+  [mastodon-config mastodon-config?
+   text string?]
+  (cond-> text
+    (:resolve-urls? mastodon-config)
+    (string/replace shortened-url-pattern resolve-url)
+    (:nitter-urls? mastodon-config)
+    (string/replace #"https://twitter.com" "https://nitter.net")))
+
+(defn-spec set-signature string?
+  [mastodon-config mastodon-config?
+   text string?]
+  (if-let [signature (:signature mastodon-config )]
+    (str text "\n" signature)
+    text))
+
+(defn post-status
+  ([mastodon-config status-text]
+   (post-status mastodon-config status-text nil print))
+  ([mastodon-config status-text media-ids]
+   (post-status mastodon-config status-text media-ids print))
+  ([mastodon-config status-text media-ids callback]
+   (let [{:keys [sensitive? signature visibility]} mastodon-config]
+     (-> (.post (mastodon-client mastodon-config) "statuses"
+                (clj->js (merge {:status (->> status-text
+                                             (resolve-urls mastodon-config)
+                                             (perform-replacements mastodon-config)
+                                             (set-signature mastodon-config))}
+                                (when media-ids {:media_ids media-ids})
+                                (when sensitive? {:sensitive sensitive?})
+                                (when visibility {:visibility visibility}))))
+         (.then #(-> % callback))))))
+
+(defn-spec post-image any?
+  [mastodon-config mastodon-config?
+   image-stream any?
+   description string?
+   callback fn?]
+  (-> (.post (mastodon-client mastodon-config) "media" 
+             #js {:file image-stream :description description})
+      (.then #(-> % .-data .-id callback))))
+
+(defn post-status-with-images
+  ([mastodon-config status-text urls]
+   (post-status-with-images mastodon-config status-text urls [] print))
+  ([mastodon-config status-text urls ids]
+   (post-status-with-images mastodon-config status-text urls ids print))
+  ([mastodon-config status-text [url & urls] ids callback]
+   (if url
+     (-> request
+         (.get url)
+         (.on "response"
+           (fn [image-stream]
+             (post-image mastodon-config image-stream status-text 
+                         #(post-status-with-images mastodon-config status-text urls (conj ids %) callback)))))
+     (post-status mastodon-config status-text (not-empty ids) callback))))
+
+(defn-spec get-mastodon-timeline any?
+  [mastodon-config mastodon-config?
+   callback fn?]
+  (.then (.get (mastodon-client mastodon-config) 
+               (str "accounts/" (:account-id mastodon-config)"/statuses") #js {})
+         #(let [response (-> % .-data infra/js->edn)]
+            (if-let [error (::error response)]
+              (infra/exit-with-error error)
+              (callback response)))))
+
+(defn-spec post-items any?
+  [mastodon-config mastodon-config?
+   last-post-time any?
+   items any?]
+  (doseq [{:keys [text media-links]} 
+          (->> items
+               (remove #((blocked-content? mastodon-config (:text %))))
+               (filter #(> (:created-at %) last-post-time)))]
+    (if media-links
+      (post-status-with-images mastodon-config text media-links)
+      (when-not (::media-only? mastodon-config)
+        (post-status mastodon-config text)))))
diff --git a/mastodon_bot/core_test.cljs b/src/test/mastodon_bot/core_test.cljs
similarity index 100%
rename from mastodon_bot/core_test.cljs
rename to src/test/mastodon_bot/core_test.cljs