diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7a17326
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+vendor/
+
+.idea/
+*.iml
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..34f0a18
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,26 @@
+{
+    "name": "thebiggive/messages",
+    "description": "Shared message / model classes for cross-service communication",
+    "type": "project",
+    "minimum-stability": "stable",
+    "prefer-stable": true,
+    "require": {
+        "php": "^8.0.2"
+    },
+    "config": {
+        "optimize-autoloader": true,
+        "sort-packages": true
+    },
+    "autoload": {
+        "psr-4": {
+            "Messages\\": "src/"
+        }
+    },
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Noel Light-Hilary",
+            "email": "noel@thebiggive.org.uk"
+        }
+    ]
+}
diff --git a/composer.lock b/composer.lock
new file mode 100644
index 0000000..b5ce306
--- /dev/null
+++ b/composer.lock
@@ -0,0 +1,20 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "edbf2a4486d4f8e497a3bbbe05fb7bf9",
+    "packages": [],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": [],
+    "prefer-stable": true,
+    "prefer-lowest": false,
+    "platform": {
+        "php": "^8.0.2"
+    },
+    "platform-dev": [],
+    "plugin-api-version": "2.2.0"
+}
diff --git a/src/Donation.php b/src/Donation.php
new file mode 100644
index 0000000..c767607
--- /dev/null
+++ b/src/Donation.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Messages;
+
+/**
+ * For now, this is just a copy of `ClaimBot\Messenger\Donation`. We may want to think
+ * about abstracting the model out to a shared dependency later.
+ */
+class Donation
+{
+    public string $id;
+
+    /** @var string Donation date, YYYY-MM-DD. */
+    public string $donation_date;
+
+    public string $title;
+    public string $first_name;
+    public string $last_name;
+    public string $house_no;
+    public string $postcode;
+    public bool $overseas = false;
+    public float $amount;
+    public bool $sponsored = false;
+    public string $org_hmrc_ref;
+    public string $org_name;
+}