diff --git a/library/events/json_base_event.nim b/library/events/json_base_event.nim
new file mode 100644
index 0000000..8c51d2c
--- /dev/null
+++ b/library/events/json_base_event.nim
@@ -0,0 +1,6 @@
+type JsonEvent* = ref object of RootObj # https://rfc.vac.dev/spec/36/#jsonsignal-type
+  eventType* {.requiresInit.}: string
+
+method `$`*(jsonEvent: JsonEvent): string {.base.} =
+  discard
+  # All events should implement this
diff --git a/library/events/json_message_ready_event.nim b/library/events/json_message_ready_event.nim
new file mode 100644
index 0000000..4a4b18f
--- /dev/null
+++ b/library/events/json_message_ready_event.nim
@@ -0,0 +1,14 @@
+import std/json
+import ./json_base_event, ../../src/[message]
+
+type JsonMessageReadyEvent* = ref object of JsonEvent
+  messageId*: MessageID
+
+proc new*(T: type JsonMessageReadyEvent, messageId: MessageID): T =
+  # Returns a MessageReady event as indicated in
+  # https://rfc.vac.dev/spec/36/#jsonmessageevent-type
+
+  return JsonMessageReadyEvent(eventType: "message_ready", messageId: messageId)
+
+method `$`*(jsonMessageReady: JsonMessageReadyEvent): string =
+  $(%*jsonMessageReady)
diff --git a/library/events/json_message_sent_event.nim b/library/events/json_message_sent_event.nim
new file mode 100644
index 0000000..714a933
--- /dev/null
+++ b/library/events/json_message_sent_event.nim
@@ -0,0 +1,14 @@
+import std/json
+import ./json_base_event, ../../src/[message]
+
+type JsonMessageSentEvent* = ref object of JsonEvent
+  messageId*: MessageID
+
+proc new*(T: type JsonMessageSentEvent, messageId: MessageID): T =
+  # Returns a MessageSent event as indicated in
+  # https://rfc.vac.dev/spec/36/#jsonmessageevent-type
+
+  return JsonMessageSentEvent(eventType: "message_sent", messageId: messageId)
+
+method `$`*(jsonMessageSent: JsonMessageSentEvent): string =
+  $(%*jsonMessageSent)
diff --git a/library/libsds.nim b/library/libsds.nim
index 2491850..162f5a9 100644
--- a/library/libsds.nim
+++ b/library/libsds.nim
@@ -5,9 +5,7 @@
 when defined(linux):
   {.passl: "-Wl,-soname,libsds.so".}
 
-import std/[locks, typetraits, tables, atomics] # Added tables
-import chronos
-import results
+import std/[locks, typetraits, tables, atomics], chronos, chronicles
 import
   ./sds_thread/sds_thread,
   ./alloc,
@@ -15,7 +13,8 @@ import
   ./sds_thread/inter_thread_communication/sds_thread_request,
   ./sds_thread/inter_thread_communication/requests/
     [sds_lifecycle_request, sds_message_request, sds_dependencies_request],
-  ../src/[reliability, reliability_utils, message]
+  ../src/[reliability, reliability_utils, message],
+  ./events/[json_message_ready_event, json_message_sent_event]
 
 ################################################################################
 ### Wrapper around the reliability manager
@@ -69,6 +68,16 @@ proc handleRequest(
 
   return RET_OK
 
+proc onMessageReady(ctx: ptr SdsContext): MessageReadyCallback =
+  return proc(messageId: MessageID) {.gcsafe.} =
+    callEventCallback(ctx, "onMessageReady"):
+      $JsonMessageReadyEvent.new(messageId)
+
+proc onMessageSent(ctx: ptr SdsContext): MessageSentCallback =
+  return proc(messageId: MessageID) {.gcsafe.} =
+    callEventCallback(ctx, "onMessageSent"):
+      $JsonMessageSentEvent.new(messageId)
+
 ### End of not-exported components
 ################################################################################
 
diff --git a/src/reliability.nim b/src/reliability.nim
index 0ad08e0..1262c7d 100644
--- a/src/reliability.nim
+++ b/src/reliability.nim
@@ -251,10 +251,9 @@ proc markDependenciesMet*(
 
 proc setCallbacks*(
     rm: ReliabilityManager,
-    onMessageReady: proc(messageId: MessageID) {.gcsafe.},
-    onMessageSent: proc(messageId: MessageID) {.gcsafe.},
-    onMissingDependencies:
-      proc(messageId: MessageID, missingDeps: seq[MessageID]) {.gcsafe.},
+    onMessageReady: MessageReadyCallback,
+    onMessageSent: MessageSentCallback,
+    onMissingDependencies: MissingDependenciesCallback,
     onPeriodicSync: PeriodicSyncCallback = nil,
 ) =
   ## Sets the callback functions for various events in the ReliabilityManager.
diff --git a/src/reliability_utils.nim b/src/reliability_utils.nim
index 25abb6d..367e965 100644
--- a/src/reliability_utils.nim
+++ b/src/reliability_utils.nim
@@ -2,8 +2,21 @@ import std/[times, locks]
 import ./[rolling_bloom_filter, message]
 
 type
+  MessageReadyCallback* = proc(messageId: MessageID) {.gcsafe.}
+
+  MessageSentCallback* = proc(messageId: MessageID) {.gcsafe.}
+
+  MissingDependenciesCallback* =
+    proc(messageId: MessageID, missingDeps: seq[MessageID]) {.gcsafe.}
+
   PeriodicSyncCallback* = proc() {.gcsafe, raises: [].}
 
+  AppCallbacks* = ref object
+    messageReadyCb*: MessageReadyCallback
+    messageSentCb*: MessageSentCallback
+    missingDependenciesCb*: MissingDependenciesCallback
+    periodicSyncCb*: PeriodicSyncCallback
+
   ReliabilityConfig* = object
     bloomFilterCapacity*: int
     bloomFilterErrorRate*: float