diff --git a/README.md b/README.md
index 02df330..d29b99e 100644
--- a/README.md
+++ b/README.md
@@ -20,4 +20,9 @@ but that we don't want to create rust bindings for (like importing stdlib.h). Th
 bindgen libCwtch.h -o src/cwtchlib_go/bindings.rs
 ```
 
+While developing you can use the `LCG_DIR` environment variable to specify the directory containing a local `libCwtch.so`
+library to override the default one.
+
+This is useful in cases where you are adding or updating APIs prior to a release.
+
 ### Todo
diff --git a/build.rs b/build.rs
index fe5dd88..75dfb48 100644
--- a/build.rs
+++ b/build.rs
@@ -7,6 +7,7 @@ use hex_literal::hex;
 use sha2::{Digest, Sha512};
 
 fn main() {
+
     // Do not fetch lib on docs.rs as it cannot, build will fail, docs won't build
     // https://docs.rs/about/builds
     if std::env::var("DOCS_RS").is_err() {
@@ -18,20 +19,24 @@ fn main() {
         println!("cargo:rerun-if-changed=libCwtch.h");
 
         let lib_cwtch_path = Path::new(&out_dir).join("libCwtch.so");
-        // https://git.openprivacy.ca/cwtch.im/libcwtch-go/releases v1.7.1
-        Command::new("wget")
-            .arg("https://git.openprivacy.ca/attachments/98184e9c-1dc7-431a-9601-91a9e763e8fc")
-            .arg("-O")
-            .arg(lib_cwtch_path)
-            .output()
-            .expect("failed to download libCwtch.so");
+        if std::env::var("LCG_DIR").is_err() {
+            // https://git.openprivacy.ca/cwtch.im/libcwtch-go/releases v1.7.1
+            Command::new("wget")
+                .arg("https://git.openprivacy.ca/attachments/98184e9c-1dc7-431a-9601-91a9e763e8fc")
+                .arg("-O")
+                .arg(lib_cwtch_path.clone())
+                .output()
+                .expect("failed to download libCwtch.so");
 
-        let lib_cwtch_path = Path::new(&out_dir).join("libCwtch.so");
-        let mut hasher = Sha512::new();
-        let mut file = fs::File::open(&lib_cwtch_path).expect("could not open lib to hash");
-        io::copy(&mut file, &mut hasher).expect("failed to copy file into hasher");
-        let hash_bytes = hasher.finalize();
+            let mut hasher = Sha512::new();
+            let mut file = fs::File::open(&lib_cwtch_path).expect("could not open lib to hash");
+            io::copy(&mut file, &mut hasher).expect("failed to copy file into hasher");
+            let hash_bytes = hasher.finalize();
 
-        assert_eq!(hash_bytes[..], hex!("cb4368d72a46f8046261c50e6e9ecf170d8e606871d5de2c1e9e34303533c344f92f5d946d7e12614581dfa3ae8e638512af7f4623ed91b1ceb1570de14bf192")[..]);
+            assert_eq!(hash_bytes[..], hex!("cb4368d72a46f8046261c50e6e9ecf170d8e606871d5de2c1e9e34303533c344f92f5d946d7e12614581dfa3ae8e638512af7f4623ed91b1ceb1570de14bf192")[..]);
+        } else {
+            let local_lcg = Path::new(std::env::var("LCG_DIR").unwrap().as_str()).join("libCwtch.so");
+            fs::copy(local_lcg, lib_cwtch_path).expect("could not find local lcg");
+        }
     }
 }