diff --git a/Cargo.toml b/Cargo.toml
index f9974e7b..b513f295 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -418,6 +418,10 @@ version = "1.0"
 default-features = false
 features = ["rc"]
 
+[workspace.dependencies.serde_core]
+version = "1.0"
+default-features = false
+
 [workspace.dependencies.serde_html_form]
 version = "0.2"
 
diff --git a/src/core/Cargo.toml b/src/core/Cargo.toml
index 90ea8bf2..0bb22988 100644
--- a/src/core/Cargo.toml
+++ b/src/core/Cargo.toml
@@ -85,6 +85,8 @@ reqwest.workspace = true
 ring.workspace = true
 ruma.workspace = true
 sanitize-filename.workspace = true
+serde_core.workspace = true
+serde_html_form.workspace = true
 serde_json.workspace = true
 serde_regex.workspace = true
 serde_yaml.workspace = true
diff --git a/src/core/error/mod.rs b/src/core/error/mod.rs
index 4de4dbfb..fd97e00f 100644
--- a/src/core/error/mod.rs
+++ b/src/core/error/mod.rs
@@ -57,6 +57,10 @@ pub enum Error {
 	#[error(transparent)]
 	Figment(#[from] figment::error::Error),
 	#[error(transparent)]
+	HtmlFormDe(#[from] serde_html_form::de::Error),
+	#[error(transparent)]
+	HtmlFormSer(#[from] serde_html_form::ser::Error),
+	#[error(transparent)]
 	Http(#[from] http::Error),
 	#[error(transparent)]
 	HttpHeader(#[from] http::header::InvalidHeaderValue),
@@ -91,6 +95,8 @@ pub enum Error {
 	#[error(transparent)]
 	TypedHeader(#[from] axum_extra::typed_header::TypedHeaderRejection),
 	#[error(transparent)]
+	UrlParse(#[from] url::ParseError),
+	#[error(transparent)]
 	Yaml(#[from] serde_yaml::Error),
 
 	// ruma/tuwunel
diff --git a/src/core/error/serde.rs b/src/core/error/serde.rs
index 0c5a153b..7566eb83 100644
--- a/src/core/error/serde.rs
+++ b/src/core/error/serde.rs
@@ -1,13 +1,11 @@
 use std::fmt::Display;
 
-use serde::{de, ser};
-
 use crate::Error;
 
-impl de::Error for Error {
+impl serde_core::de::Error for Error {
 	fn custom<T: Display + ToString>(msg: T) -> Self { Self::SerdeDe(msg.to_string().into()) }
 }
 
-impl ser::Error for Error {
+impl serde_core::ser::Error for Error {
 	fn custom<T: Display + ToString>(msg: T) -> Self { Self::SerdeSer(msg.to_string().into()) }
 }