diff --git a/Cargo.lock b/Cargo.lock
index d8843203ba..7109658162 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5494,6 +5494,7 @@ version = "0.1.0"
 dependencies = [
  "dotenvy",
  "log",
+ "regex",
  "schemars",
  "serde",
  "url",
diff --git a/common/network-defaults/Cargo.toml b/common/network-defaults/Cargo.toml
index 2cd2d4c443..cff301d891 100644
--- a/common/network-defaults/Cargo.toml
+++ b/common/network-defaults/Cargo.toml
@@ -23,3 +23,6 @@ default = ["env", "network"]
 env = ["dotenvy", "log"]
 network = ["schemars", "serde", "url"]
 utoipa = [ "dep:utoipa" ]
+
+[build-dependencies]
+regex = { workspace = true }
diff --git a/common/network-defaults/build.rs b/common/network-defaults/build.rs
new file mode 100644
index 0000000000..067db307dc
--- /dev/null
+++ b/common/network-defaults/build.rs
@@ -0,0 +1,64 @@
+use regex::Regex;
+use std::{collections::HashMap, fs};
+
+const TARGET_ENV_FILE: &str = "../../envs/mainnet.env";
+
+/// Sync variable values defined in code with .env file
+fn main() {
+    let file = include_str!("src/mainnet.rs");
+
+    let variables_to_track = [
+        "NETWORK_NAME",
+        "BECH32_PREFIX",
+        "MIXNET_CONTRACT_ADDRESS",
+        "VESTING_CONTRACT_ADDRESS",
+        "GROUP_CONTRACT_ADDRESS",
+        "ECASH_CONTRACT_ADDRESS",
+        "MULTISIG_CONTRACT_ADDRESS",
+        "COCONUT_DKG_CONTRACT_ADDRESS",
+        "REWARDING_VALIDATOR_ADDRESS",
+        "NYM_API",
+        "NYXD_WS",
+        "EXPLORER_API",
+        "NYM_VPN_API",
+    ];
+
+    let mut replace_with = HashMap::new();
+
+    for var in variables_to_track {
+        // if script fails, debug with `cargo check -vv``
+        println!("Looking for {}", var);
+
+        // read pattern that looks like:
+        // <var>: &str = "<whatever is between quotes>"
+        let pattern = format!(r#"{}: &str\s*=\s*"([^"]*)""#, regex::escape(var));
+
+        let re = Regex::new(&pattern).unwrap();
+        let value = re
+            .captures(file)
+            .and_then(|caps| caps.get(1).map(|match_| match_.as_str().to_string()))
+            .expect("Couldn't find var in source file");
+        println!("Storing {}={}", var, value);
+        replace_with.insert(var, value);
+    }
+
+    let mut contents = fs::read_to_string(TARGET_ENV_FILE).unwrap();
+
+    for (var, value) in replace_with {
+        // match a pattern that looks like:
+        // <var> = "<value>"
+        // where `<var>` is a variable name inserted into search pattern
+        let pattern = format!(r#"{}\s*=\s*"([^"]*)""#, regex::escape(var));
+
+        // replace matched pattern with
+        // <var>="<value>"
+        let re = Regex::new(&pattern).unwrap();
+        contents = re
+            .replace(&contents, |_: &regex::Captures| {
+                format!(r#"{}="{}""#, var, value)
+            })
+            .to_string();
+    }
+
+    fs::write(TARGET_ENV_FILE, contents).unwrap();
+}
diff --git a/envs/mainnet.env b/envs/mainnet.env
index e40e54a471..2be5300bd0 100644
--- a/envs/mainnet.env
+++ b/envs/mainnet.env
@@ -25,4 +25,4 @@ NYXD="https://rpc.nymtech.net"
 NYM_API="https://validator.nymtech.net/api/"
 NYXD_WS="wss://rpc.nymtech.net/websocket"
 EXPLORER_API="https://explorer.nymtech.net/api/"
-NYM_VPN_API="https://nymvpn.com/api"
+NYM_VPN_API="https://nymvpn.net/api/"