diff --git a/app/src/main/assets/stickers/flamenet.core.json b/app/src/main/assets/stickers/flamenet.core.json
new file mode 100644
index 0000000..d43933d
--- /dev/null
+++ b/app/src/main/assets/stickers/flamenet.core.json
@@ -0,0 +1,31 @@
+{
+  "pack": "flamenet.core",
+  "name": "Flamenet",
+  "fallback": "🙂",
+  "stickers": [
+    { "id": "wave",     "glyph": "👋", "name": "Wave" },
+    { "id": "yes",      "glyph": "👍", "name": "Yes" },
+    { "id": "no",       "glyph": "👎", "name": "No" },
+    { "id": "laugh",    "glyph": "😂", "name": "Laughing" },
+    { "id": "love",     "glyph": "❤️", "name": "Love" },
+    { "id": "party",    "glyph": "🎉", "name": "Party" },
+    { "id": "think",    "glyph": "🤔", "name": "Thinking" },
+    { "id": "cry",      "glyph": "😭", "name": "Crying" },
+    { "id": "fire",     "glyph": "🔥", "name": "Fire" },
+    { "id": "clap",     "glyph": "👏", "name": "Applause" },
+    { "id": "sleep",    "glyph": "😴", "name": "Sleeping" },
+    { "id": "eyes",     "glyph": "👀", "name": "Looking" },
+    { "id": "ok",       "glyph": "👌", "name": "OK" },
+    { "id": "pray",     "glyph": "🙏", "name": "Please" },
+    { "id": "strong",   "glyph": "💪", "name": "Strong" },
+    { "id": "coffee",   "glyph": "☕", "name": "Coffee" },
+    { "id": "rocket",   "glyph": "🚀", "name": "Rocket" },
+    { "id": "bug",      "glyph": "🐛", "name": "Bug" },
+    { "id": "check",    "glyph": "✅", "name": "Done" },
+    { "id": "warning",  "glyph": "⚠️", "name": "Careful" },
+    { "id": "wave-bye", "glyph": "🫡", "name": "Salute" },
+    { "id": "shrug",    "glyph": "🤷", "name": "Shrug" },
+    { "id": "star",     "glyph": "⭐", "name": "Star" },
+    { "id": "cake",     "glyph": "🎂", "name": "Cake" }
+  ]
+}
diff --git a/engine/src/main/kotlin/io/flamenet/e2e/Content.kt b/engine/src/main/kotlin/io/flamenet/e2e/Content.kt
index fb0eefa..23b1041 100644
--- a/engine/src/main/kotlin/io/flamenet/e2e/Content.kt
+++ b/engine/src/main/kotlin/io/flamenet/e2e/Content.kt
@@ -49,8 +49,31 @@ data class Content(
     /** Set iff this is a reaction: the emoji, or empty to take one back. */
     val reaction: String? = null,
     val call: CallSignal? = null,
+    /** Set iff this is a sticker: which pack, and which one in it. */
+    val sticker: Sticker? = null,
 ) {
 
+    /**
+     * A sticker: an id, never an image.
+     *
+     * 🔴 Sending the picture would cost an upload and a download of bytes both
+     * ends already ship with, on every sticker. The receiver draws it from its
+     * own pack, so this is about sixty bytes on the wire. See docs/STICKERS.md.
+     *
+     * ⚠️ An unknown pack or id must degrade, never break — the renderer falls
+     * back rather than showing an empty bubble.
+     */
+    data class Sticker(val pack: String, val id: String) {
+        fun toJson(): JSONObject = JSONObject().put("pack", pack).put("id", id)
+
+        companion object {
+            fun fromJson(json: JSONObject) = Sticker(
+                pack = json.optString("pack"),
+                id = json.optString("id"),
+            )
+        }
+    }
+
     /**
      * A pointer at an earlier message.
      *
@@ -107,6 +130,9 @@ data class Content(
         const val TEXT = "text"
         const val REACT = "react"
 
+        /** A sticker: renderable, but never as text. See docs/STICKERS.md. */
+        const val STICKER = "sticker"
+
         /** A contact's delivery key, so we can be reached sealed (§14.4). */
         const val DELIVERY_KEY = "delivery_key"
 
@@ -191,6 +217,20 @@ data class Content(
         fun reaction(emoji: String, about: Reference, groupId: String? = null): String =
             assemble("react", caption = emoji, groupId = groupId, about = about)
 
+        /**
+         * ⚠️ Hand-ordered like the rest: the receive side's marker check
+         * matches the serialized prefix, so `fnc` has to come first.
+         */
+        fun sticker(pack: String, id: String, groupId: String? = null,
+                    messageId: String? = null): String {
+            val stk = JSONObject().put("pack", pack).put("id", id)
+            val parts = mutableListOf("\"fnc\":1", "\"kind\":${quote(Kind.STICKER)}")
+            if (messageId != null) parts += "\"mid\":${quote(messageId)}"
+            parts += "\"stk\":$stk"
+            if (groupId != null) parts += "\"gid\":${quote(groupId)}"
+            return "{" + parts.joinToString(",") + "}"
+        }
+
         fun callSignal(signal: CallSignal): String {
             val call = JSONObject().put("id", signal.callId)
             signal.sdp?.let { call.put("sdp", it) }
@@ -252,6 +292,17 @@ data class Content(
                     messageId = messageId, about = about, reaction = caption)
             }
 
+            // A sticker is renderable but is NOT text: it draws as a glyph with
+            // no bubble, so it has to be recognised here rather than falling
+            // through to the text path and rendering as an empty message.
+            if (kind == Kind.STICKER) {
+                val stk = json.optJSONObject("stk")
+                if (stk != null) {
+                    return Content("", kind = kind, raw = json, groupId = groupId,
+                        messageId = messageId, sticker = Sticker.fromJson(stk))
+                }
+            }
+
             // Control traffic. Returned with its envelope so the caller can act
             // on it, and never renderable.
             //