diff --git a/config/config.exs b/config/config.exs
index cf13cb1..a43af46 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -48,7 +48,8 @@ config :spark,
 
 config :mv,
   ecto_repos: [Mv.Repo],
-  generators: [timestamp_type: :utc_datetime]
+  generators: [timestamp_type: :utc_datetime],
+  ash_domains: [Mv.Membership]
 
 # Configures the endpoint
 config :mv, MvWeb.Endpoint,
diff --git a/lib/membership/member.ex b/lib/membership/member.ex
new file mode 100644
index 0000000..0538f45
--- /dev/null
+++ b/lib/membership/member.ex
@@ -0,0 +1,35 @@
+defmodule Mv.Membership.Member do
+  use Ash.Resource,
+    domain: Mv.Membership,
+    data_layer: AshPostgres.DataLayer
+
+  postgres do
+    table "members"
+    repo Mv.Repo
+  end
+
+  actions do
+    defaults [:read, :destroy]
+
+    create :create_member do
+      primary? true
+      argument :properties, {:array, :map}
+      change manage_relationship(:properties, type: :create)
+    end
+
+    update :update_member do
+      primary? true
+      require_atomic? false
+      argument :properties, {:array, :map}
+      change manage_relationship(:properties, on_match: :update, on_no_match: :create)
+    end
+  end
+
+  attributes do
+    uuid_v7_primary_key :id
+  end
+
+  relationships do
+    has_many :properties, Mv.Membership.Property
+  end
+end
diff --git a/lib/membership/membership.ex b/lib/membership/membership.ex
new file mode 100644
index 0000000..b766a13
--- /dev/null
+++ b/lib/membership/membership.ex
@@ -0,0 +1,27 @@
+defmodule Mv.Membership do
+  use Ash.Domain,
+    extensions: [AshPhoenix]
+
+  resources do
+    resource Mv.Membership.Member do
+      define :create_member, action: :create_member
+      define :list_members, action: :read
+      define :update_member, action: :update_member
+      define :destroy_member, action: :destroy
+    end
+
+    resource Mv.Membership.Property do
+      define :create_property, action: :create
+      define :list_property, action: :read
+      define :update_property, action: :update
+      define :destroy_property, action: :destroy
+    end
+
+    resource Mv.Membership.PropertyType do
+      define :create_property_type, action: :create
+      define :list_property_types, action: :read
+      define :update_property_type, action: :update
+      define :destroy_property_type, action: :destroy
+    end
+  end
+end
diff --git a/lib/membership/property.ex b/lib/membership/property.ex
new file mode 100644
index 0000000..433fc63
--- /dev/null
+++ b/lib/membership/property.ex
@@ -0,0 +1,28 @@
+defmodule Mv.Membership.Property do
+  use Ash.Resource,
+    domain: Mv.Membership,
+    data_layer: AshPostgres.DataLayer
+
+  postgres do
+    table "properties"
+    repo Mv.Repo
+  end
+
+  actions do
+    defaults [:create, :read, :update, :destroy]
+    default_accept [:value, :member_id, :property_type_id]
+  end
+
+  attributes do
+    uuid_primary_key :id
+
+    attribute :value, :string,
+      description: "Speichert den Wert, Typ-Interpretation per property_type.typ"
+  end
+
+  relationships do
+    belongs_to :member, Mv.Membership.Member
+
+    belongs_to :property_type, Mv.Membership.PropertyType
+  end
+end
diff --git a/lib/membership/property_type.ex b/lib/membership/property_type.ex
new file mode 100644
index 0000000..560f679
--- /dev/null
+++ b/lib/membership/property_type.ex
@@ -0,0 +1,43 @@
+defmodule Mv.Membership.PropertyType do
+  use Ash.Resource,
+    domain: Mv.Membership,
+    data_layer: AshPostgres.DataLayer
+
+  postgres do
+    table "property_types"
+    repo Mv.Repo
+  end
+
+  actions do
+    defaults [:create, :read, :update, :destroy]
+    default_accept [:name, :type, :description, :immutable, :required]
+  end
+
+  attributes do
+    uuid_primary_key :id
+
+    attribute :name, :string, allow_nil?: false, public?: true
+
+    attribute :type, :string,
+      allow_nil?: false,
+      description: "Definies the datatype `Property.value` is interpreted as"
+
+    attribute :description, :string, allow_nil?: true, public?: true
+
+    attribute :immutable, :boolean,
+      default: false,
+      allow_nil?: false
+
+    attribute :required, :boolean,
+      default: false,
+      allow_nil?: false
+  end
+
+  relationships do
+    has_many :properties, Mv.Membership.Property
+  end
+
+  identities do
+    identity :unique_name, [:name]
+  end
+end
diff --git a/priv/repo/migrations/20250514151922_initial_migration.exs b/priv/repo/migrations/20250514151922_initial_migration.exs
new file mode 100644
index 0000000..64915c2
--- /dev/null
+++ b/priv/repo/migrations/20250514151922_initial_migration.exs
@@ -0,0 +1,72 @@
+defmodule Mv.Repo.Migrations.InitialMigration do
+  @moduledoc """
+  Updates resources based on their most recent snapshots.
+
+  This file was autogenerated with `mix ash_postgres.generate_migrations`
+  """
+
+  use Ecto.Migration
+
+  def up do
+    create table(:property_types, primary_key: false) do
+      add :id, :uuid, null: false, default: fragment("gen_random_uuid()"), primary_key: true
+      add :name, :text, null: false
+      add :type, :text, null: false
+      add :description, :text
+      add :immutable, :boolean, null: false, default: false
+      add :required, :boolean, null: false, default: false
+    end
+
+    create unique_index(:property_types, [:name], name: "property_types_unique_name_index")
+
+    create table(:properties, primary_key: false) do
+      add :id, :uuid, null: false, default: fragment("gen_random_uuid()"), primary_key: true
+      add :value, :text
+      add :member_id, :uuid
+      add :property_type_id, :uuid
+    end
+
+    create table(:members, primary_key: false) do
+      add :id, :uuid, null: false, default: fragment("uuid_generate_v7()"), primary_key: true
+    end
+
+    alter table(:properties) do
+      modify :member_id,
+             references(:members,
+               column: :id,
+               name: "properties_member_id_fkey",
+               type: :uuid,
+               prefix: "public"
+             )
+
+      modify :property_type_id,
+             references(:property_types,
+               column: :id,
+               name: "properties_property_type_id_fkey",
+               type: :uuid,
+               prefix: "public"
+             )
+    end
+  end
+
+  def down do
+    drop constraint(:properties, "properties_member_id_fkey")
+
+    drop constraint(:properties, "properties_property_type_id_fkey")
+
+    alter table(:properties) do
+      modify :property_type_id, :uuid
+      modify :member_id, :uuid
+    end
+
+    drop table(:members)
+
+    drop table(:properties)
+
+    drop_if_exists unique_index(:property_types, [:name],
+                     name: "property_types_unique_name_index"
+                   )
+
+    drop table(:property_types)
+  end
+end
diff --git a/priv/repo/seeds.exs b/priv/repo/seeds.exs
index 456772e..8fca144 100644
--- a/priv/repo/seeds.exs
+++ b/priv/repo/seeds.exs
@@ -9,3 +9,31 @@
 #
 # We recommend using the bang functions (`insert!`, `update!`
 # and so on) as they will fail if something goes wrong.
+
+alias Mv.Membership
+
+for attrs <- [
+      %{
+        name: "Vorname",
+        type: "string",
+        description: "Vorname des Mitglieds",
+        immutable: true,
+        required: true
+      },
+      %{
+        name: "Email",
+        type: "string",
+        description: "Email-Adresse des Mitglieds",
+        immutable: true,
+        required: true
+      }
+    ] do
+  # upsert?: true sorgt dafür, dass bei bestehendem Namen kein Fehler, 
+  # sondern ein Update (hier effektiv No-Op) ausgeführt wird
+  {:ok, _} =
+    Membership.create_property_type(
+      attrs,
+      upsert?: true,
+      upsert_identity: :unique_name
+    )
+end
diff --git a/priv/resource_snapshots/repo/members/20250514151922.json b/priv/resource_snapshots/repo/members/20250514151922.json
new file mode 100644
index 0000000..df811d8
--- /dev/null
+++ b/priv/resource_snapshots/repo/members/20250514151922.json
@@ -0,0 +1,29 @@
+{
+  "attributes": [
+    {
+      "allow_nil?": false,
+      "default": "fragment(\"uuid_generate_v7()\")",
+      "generated?": false,
+      "primary_key?": true,
+      "references": null,
+      "size": null,
+      "source": "id",
+      "type": "uuid"
+    }
+  ],
+  "base_filter": null,
+  "check_constraints": [],
+  "custom_indexes": [],
+  "custom_statements": [],
+  "has_create_action": true,
+  "hash": "A0402269CB456075B81CA4CB3A2135A2C88D8B7FD51CD7A23084AA5264FEE344",
+  "identities": [],
+  "multitenancy": {
+    "attribute": null,
+    "global": null,
+    "strategy": null
+  },
+  "repo": "Elixir.Mv.Repo",
+  "schema": null,
+  "table": "members"
+}
\ No newline at end of file
diff --git a/priv/resource_snapshots/repo/properties/20250514151922.json b/priv/resource_snapshots/repo/properties/20250514151922.json
new file mode 100644
index 0000000..0707bcf
--- /dev/null
+++ b/priv/resource_snapshots/repo/properties/20250514151922.json
@@ -0,0 +1,97 @@
+{
+  "attributes": [
+    {
+      "allow_nil?": false,
+      "default": "fragment(\"gen_random_uuid()\")",
+      "generated?": false,
+      "primary_key?": true,
+      "references": null,
+      "size": null,
+      "source": "id",
+      "type": "uuid"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": false,
+      "references": null,
+      "size": null,
+      "source": "value",
+      "type": "text"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": false,
+      "references": {
+        "deferrable": false,
+        "destination_attribute": "id",
+        "destination_attribute_default": null,
+        "destination_attribute_generated": null,
+        "index?": false,
+        "match_type": null,
+        "match_with": null,
+        "multitenancy": {
+          "attribute": null,
+          "global": null,
+          "strategy": null
+        },
+        "name": "properties_member_id_fkey",
+        "on_delete": null,
+        "on_update": null,
+        "primary_key?": true,
+        "schema": "public",
+        "table": "members"
+      },
+      "size": null,
+      "source": "member_id",
+      "type": "uuid"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": false,
+      "references": {
+        "deferrable": false,
+        "destination_attribute": "id",
+        "destination_attribute_default": null,
+        "destination_attribute_generated": null,
+        "index?": false,
+        "match_type": null,
+        "match_with": null,
+        "multitenancy": {
+          "attribute": null,
+          "global": null,
+          "strategy": null
+        },
+        "name": "properties_property_type_id_fkey",
+        "on_delete": null,
+        "on_update": null,
+        "primary_key?": true,
+        "schema": "public",
+        "table": "property_types"
+      },
+      "size": null,
+      "source": "property_type_id",
+      "type": "uuid"
+    }
+  ],
+  "base_filter": null,
+  "check_constraints": [],
+  "custom_indexes": [],
+  "custom_statements": [],
+  "has_create_action": true,
+  "hash": "F2A42A3427E0428637F465E4F357A3BE21B33231F94CF77B4843084128F6BDA5",
+  "identities": [],
+  "multitenancy": {
+    "attribute": null,
+    "global": null,
+    "strategy": null
+  },
+  "repo": "Elixir.Mv.Repo",
+  "schema": null,
+  "table": "properties"
+}
\ No newline at end of file
diff --git a/priv/resource_snapshots/repo/property_types/20250514151922.json b/priv/resource_snapshots/repo/property_types/20250514151922.json
new file mode 100644
index 0000000..5da5fa8
--- /dev/null
+++ b/priv/resource_snapshots/repo/property_types/20250514151922.json
@@ -0,0 +1,94 @@
+{
+  "attributes": [
+    {
+      "allow_nil?": false,
+      "default": "fragment(\"gen_random_uuid()\")",
+      "generated?": false,
+      "primary_key?": true,
+      "references": null,
+      "size": null,
+      "source": "id",
+      "type": "uuid"
+    },
+    {
+      "allow_nil?": false,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": false,
+      "references": null,
+      "size": null,
+      "source": "name",
+      "type": "text"
+    },
+    {
+      "allow_nil?": false,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": false,
+      "references": null,
+      "size": null,
+      "source": "type",
+      "type": "text"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": false,
+      "references": null,
+      "size": null,
+      "source": "description",
+      "type": "text"
+    },
+    {
+      "allow_nil?": false,
+      "default": "false",
+      "generated?": false,
+      "primary_key?": false,
+      "references": null,
+      "size": null,
+      "source": "immutable",
+      "type": "boolean"
+    },
+    {
+      "allow_nil?": false,
+      "default": "false",
+      "generated?": false,
+      "primary_key?": false,
+      "references": null,
+      "size": null,
+      "source": "required",
+      "type": "boolean"
+    }
+  ],
+  "base_filter": null,
+  "check_constraints": [],
+  "custom_indexes": [],
+  "custom_statements": [],
+  "has_create_action": true,
+  "hash": "47210108DE1E7B2A20A67205E875B3440526941E61AB95B166976E8CD8AA0955",
+  "identities": [
+    {
+      "all_tenants?": false,
+      "base_filter": null,
+      "index_name": "property_types_unique_name_index",
+      "keys": [
+        {
+          "type": "atom",
+          "value": "name"
+        }
+      ],
+      "name": "unique_name",
+      "nils_distinct?": true,
+      "where": null
+    }
+  ],
+  "multitenancy": {
+    "attribute": null,
+    "global": null,
+    "strategy": null
+  },
+  "repo": "Elixir.Mv.Repo",
+  "schema": null,
+  "table": "property_types"
+}
\ No newline at end of file