diff --git a/crates/ptth_relay/src/config.rs b/crates/ptth_relay/src/config.rs
index 389340e..4e204f6 100644
--- a/crates/ptth_relay/src/config.rs
+++ b/crates/ptth_relay/src/config.rs
@@ -15,10 +15,25 @@ use crate::{
 	},
 };
 
+/// Machine-editable configs.
+/// These are stored in the `data` directory and shouldn't be touched by
+/// humans. ptth_relay will re-write them while it's running.
+
+mod machine_editable {
+	use serde::{Deserialize, Serialize};
+	
+	use super::file::Server;
+	
+	#[derive (Deserialize, Serialize)]
+	pub struct Config {
+		pub servers: Option <Vec <Server>>,
+	}
+}
+
 /// Config fields as they are loaded from the config file
 
 pub mod file {
-	use serde::Deserialize;
+	use serde::{Deserialize, Serialize};
 	
 	use crate::key_validity::{
 		BlakeHashWrapper,
@@ -26,7 +41,7 @@ pub mod file {
 		Valid30Days,
 	};
 	
-	#[derive (Deserialize)]
+	#[derive (Deserialize, Serialize)]
 	pub struct Server {
 		/// This is duplicated in the hashmap, but it's not a problem
 		pub name: String,
diff --git a/crates/ptth_relay/src/key_validity.rs b/crates/ptth_relay/src/key_validity.rs
index 95ddc11..bc19223 100644
--- a/crates/ptth_relay/src/key_validity.rs
+++ b/crates/ptth_relay/src/key_validity.rs
@@ -12,6 +12,7 @@ use serde::{
 	},
 	Deserialize, 
 	Deserializer,
+	Serialize,
 };
 
 #[derive (Copy, Clone, PartialEq, Eq)]
@@ -70,6 +71,13 @@ impl <'de> Deserialize <'de> for BlakeHashWrapper {
 	}
 }
 
+impl Serialize for BlakeHashWrapper {
+	fn serialize <S: serde::Serializer> (&self, serializer: S) -> Result <S::Ok, S::Error>
+	{
+		serializer.serialize_str (&self.encode_base64 ())
+	}
+}
+
 pub struct Valid7Days;
 pub struct Valid30Days;
 //pub struct Valid90Days;
@@ -166,9 +174,19 @@ impl <V: MaxValidDuration> ScraperKey <V> {
 #[cfg (test)]
 mod tests {
 	use chrono::{Utc};
+	use serde_json::json;
 	use super::*;
 	use KeyValidity::*;
 	
+	#[test]
+	fn roundtrip_tripcode () {
+		let tripcode = "m8vG/sQnsn/87CQ5Ob6wMJeAnMKtXYfCBLNZ1SrSkvI=";
+		
+		let j = json! ({
+			"tripcode": tripcode,
+		});
+	}
+	
 	#[test]
 	fn duration_negative () {
 		let zero_time = Utc::now ();