diff --git a/Cargo.toml b/Cargo.toml
index 6336b33..279d1f6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,6 +13,7 @@ sea-orm = { version = "0.12.14", features = ["macros", "sqlx-sqlite", "runtime-t
 sea-orm-migration = "0.12.15"
 serde = { version = "1.0.193", features = ["derive"] }
 serde_json = "1.0.108"
+thiserror = "1.0.58"
 tokio = { version = "1.35.1", features = ["full"] }
 tracing = "0.1.40"
 tracing-subscriber = "0.3.18"
diff --git a/src/model/activity.rs b/src/model/activity.rs
index 44f437d..72207e5 100644
--- a/src/model/activity.rs
+++ b/src/model/activity.rs
@@ -54,3 +54,16 @@ impl activitystream::Activity for Model {
 		self.target.as_deref()
 	}
 }
+
+impl Model {
+	pub fn new(activity: &impl activitystream::Activity) -> Result<Self, super::FieldError> {
+		Ok(Model {
+			id: activity.id().ok_or(super::FieldError("id"))?.to_string(),
+			activity_type: activity.activity_type().ok_or(super::FieldError("type"))?,
+			actor: activity.actor_id().ok_or(super::FieldError("actor"))?.to_string(),
+			object: activity.object_id().map(|x| x.to_string()),
+			target: activity.target().map(|x| x.to_string()),
+			published: activity.published().ok_or(super::FieldError("published"))?,
+		})
+	}
+}
diff --git a/src/model/mod.rs b/src/model/mod.rs
index 6e07293..4d5cf44 100644
--- a/src/model/mod.rs
+++ b/src/model/mod.rs
@@ -2,6 +2,10 @@ pub mod user;
 pub mod object;
 pub mod activity;
 
+#[derive(Debug, Clone, thiserror::Error)]
+#[error("missing required field: '{0}'")]
+pub struct FieldError(&'static str);
+
 pub async fn faker(db: &sea_orm::DatabaseConnection) -> Result<(), sea_orm::DbErr> {
 	use sea_orm::EntityTrait;
 
diff --git a/src/model/object.rs b/src/model/object.rs
index 49abbed..d6c05a8 100644
--- a/src/model/object.rs
+++ b/src/model/object.rs
@@ -1,6 +1,6 @@
 use sea_orm::entity::prelude::*;
 
-use crate::activitystream::types::ObjectType;
+use crate::activitystream::{self, types::ObjectType};
 
 #[derive(Clone, Debug, PartialEq, DeriveEntityModel, Eq)]
 #[sea_orm(table_name = "objects")]
@@ -50,3 +50,20 @@ impl crate::activitystream::Object for Model {
 		Some(self.published)
 	}
 }
+
+impl Model {
+	pub fn new(object: &impl activitystream::Object) -> Result<Self, super::FieldError> {
+		let Some(activitystream::Type::ObjectType(t)) = object.full_type() else {
+			return Err(super::FieldError("type")); // TODO maybe just wrong? better errors!
+		};
+		Ok(Model {
+			id: object.id().ok_or(super::FieldError("id"))?.to_string(),
+			object_type: t,
+			attributed_to: object.attributed_to().map(|x| x.to_string()),
+			name: object.name().map(|x| x.to_string()),
+			summary: object.summary().map(|x| x.to_string()),
+			content: object.content().map(|x| x.to_string()),
+			published: object.published().ok_or(super::FieldError("published"))?,
+		})
+	}
+}
diff --git a/src/model/user.rs b/src/model/user.rs
index 755fef3..2b8475f 100644
--- a/src/model/user.rs
+++ b/src/model/user.rs
@@ -1,4 +1,3 @@
-
 use sea_orm::entity::prelude::*;
 
 use crate::activitystream::{self, types::ActorType};
@@ -33,3 +32,16 @@ impl activitystream::Object for Model {
 		Some(&self.name)
 	}
 }
+
+impl Model {
+	pub fn new(object: &impl activitystream::Object) -> Result<Self, super::FieldError> {
+		let Some(activitystream::Type::ActorType(t)) = object.full_type() else {
+			return Err(super::FieldError("type")); // TODO maybe just wrong? better errors!
+		};
+		Ok(Model {
+			id: object.id().ok_or(super::FieldError("id"))?.to_string(),
+			actor_type: t,
+			name: object.name().ok_or(super::FieldError("name"))?.to_string(),
+		})
+	}
+}