diff --git a/Cargo.lock b/Cargo.lock
index 3827fd3..b4935f1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -815,7 +815,7 @@ checksum = "953ec861398dccce10c670dfeaf3ec4911ca479e9c02154b3a215178c5f566f2"
 
 [[package]]
 name = "postwoman"
-version = "0.4.0"
+version = "0.4.1"
 dependencies = [
  "base64",
  "chrono",
diff --git a/src/ext.rs b/src/ext.rs
index a0ad897..f0f2887 100644
--- a/src/ext.rs
+++ b/src/ext.rs
@@ -38,3 +38,23 @@ pub fn stringify_json(v: &serde_json::Value) -> String {
 pub fn full_name(namespace: &str, name: &str) -> String {
 	format!("{namespace}:{name}")
 }
+
+pub trait FillableFromEnvironment {
+	fn fill(self, env: &toml::Table) -> Self;
+
+	fn default_vars(env: &toml::Table) -> std::collections::HashMap<String, String> {
+		let mut vars: std::collections::HashMap<String, String> = std::collections::HashMap::default();
+
+		vars.insert("POSTWOMAN_TIMESTAMP".to_string(), chrono::Local::now().timestamp().to_string());
+
+		for (k, v) in env {
+			vars.insert(k.to_string(), stringify_toml(v));
+		}
+
+		for (k, v) in std::env::vars() {
+			vars.insert(k, v);
+		}
+
+		vars
+	}
+}
diff --git a/src/model/client.rs b/src/model/client.rs
index ad7bf04..a9ea0c6 100644
--- a/src/model/client.rs
+++ b/src/model/client.rs
@@ -1,3 +1,5 @@
+use crate::ext::FillableFromEnvironment;
+
 
 #[derive(Debug, Default, Clone, serde::Serialize, serde::Deserialize)]
 pub struct ClientConfig {
@@ -12,3 +14,23 @@ pub struct ClientConfig {
 	/// accept invalid SSL certificates, defaults to false (be careful: this is dangerous!)
 	pub accept_invalid_certs: Option<bool>,
 }
+
+impl FillableFromEnvironment for ClientConfig {
+	fn fill(mut self, env: &toml::Table) -> Self {
+		let vars = Self::default_vars(env);
+
+		for (k, v) in vars {
+			let k_var = format!("${{{k}}}");
+
+			if let Some(base) = self.base {
+				self.base = Some(base.replace(&k_var, &v));
+			}
+
+			if let Some(user_agent) = self.user_agent {
+				self.user_agent = Some(user_agent.replace(&k_var, &v));
+			}
+		}
+
+		self
+	}
+}
diff --git a/src/model/endpoint.rs b/src/model/endpoint.rs
index 0e5d1e0..8851e11 100644
--- a/src/model/endpoint.rs
+++ b/src/model/endpoint.rs
@@ -8,7 +8,7 @@ use jaq_interpret::FilterT;
 use crate::errors::InvalidHeaderError;
 use crate::{PostWomanError, APP_USER_AGENT};
 
-use crate::ext::{stringify_toml, stringify_json, StringOr};
+use crate::ext::{stringify_json, stringify_toml, FillableFromEnvironment, StringOr};
 use super::{ExtractorConfig, ClientConfig};
 
 
@@ -75,57 +75,6 @@ impl EndpointConfig {
 		url
 	}
 
-	pub fn fill(mut self, env: &toml::Table) -> Self {
-		let mut vars: HashMap<String, String> = HashMap::default();
-
-		vars.insert("POSTWOMAN_TIMESTAMP".to_string(), chrono::Local::now().timestamp().to_string());
-
-		for (k, v) in env {
-			vars.insert(k.to_string(), stringify_toml(v));
-		}
-
-		for (k, v) in std::env::vars() {
-			vars.insert(k, v);
-		}
-
-		for (k, v) in vars {
-			let k_var = format!("${{{k}}}");
-			self.path = self.path.replace(&k_var, &v);
-			if let Some(method) = self.method {
-				self.method = Some(method.replace(&k_var, &v));
-			}
-			if let Some(b) = self.body {
-				match b {
-					StringOr::Str(body) => {
-						self.body = Some(StringOr::Str(body.replace(&k_var, &v)));
-					},
-					StringOr::T(json) => {
-						let wrap = toml::Value::Table(json.clone());
-						let toml::Value::Table(out) = replace_recursive(wrap, &k_var, &v)
-						else { unreachable!("we put in a table, we get out a table") };
-						self.body = Some(StringOr::T(out));
-					},
-				}
-			}
-			if let Some(query) = self.query {
-				self.query = Some(
-					query.into_iter()
-						.map(|x| x.replace(&k_var, &v))
-						.collect()
-				);
-			}
-			if let Some(headers) = self.headers {
-				self.headers = Some(
-					headers.into_iter()
-						.map(|x| x.replace(&k_var, &v))
-						.collect()
-				);
-			}
-		}
-		
-		self
-	}
-
 	pub async fn execute(self, opts: &ClientConfig) -> Result<String, PostWomanError> {
 		let body = self.body()?;
 		let method = self.method()?;
@@ -196,6 +145,49 @@ impl EndpointConfig {
 	}
 }
 
+impl FillableFromEnvironment for EndpointConfig {
+	fn fill(mut self, env: &toml::Table) -> Self {
+		let vars = Self::default_vars(env);
+
+		for (k, v) in vars {
+			let k_var = format!("${{{k}}}");
+			self.path = self.path.replace(&k_var, &v);
+			if let Some(method) = self.method {
+				self.method = Some(method.replace(&k_var, &v));
+			}
+			if let Some(b) = self.body {
+				match b {
+					StringOr::Str(body) => {
+						self.body = Some(StringOr::Str(body.replace(&k_var, &v)));
+					},
+					StringOr::T(json) => {
+						let wrap = toml::Value::Table(json.clone());
+						let toml::Value::Table(out) = replace_recursive(wrap, &k_var, &v)
+						else { unreachable!("we put in a table, we get out a table") };
+						self.body = Some(StringOr::T(out));
+					},
+				}
+			}
+			if let Some(query) = self.query {
+				self.query = Some(
+					query.into_iter()
+						.map(|x| x.replace(&k_var, &v))
+						.collect()
+				);
+			}
+			if let Some(headers) = self.headers {
+				self.headers = Some(
+					headers.into_iter()
+						.map(|x| x.replace(&k_var, &v))
+						.collect()
+				);
+			}
+		}
+		
+		self
+	}
+}
+
 fn replace_recursive(element: toml::Value, from: &str, to: &str) -> toml::Value {
 	match element {
 		toml::Value::Float(x) => toml::Value::Float(x),