diff --git a/plonky2x/core/src/backend/function/mod.rs b/plonky2x/core/src/backend/function/mod.rs
index 5e3f4e977..337a3feab 100644
--- a/plonky2x/core/src/backend/function/mod.rs
+++ b/plonky2x/core/src/backend/function/mod.rs
@@ -4,7 +4,7 @@ pub mod result;
 
 use std::fs::File;
 use std::io::{BufReader, Write};
-use std::{fs, path};
+use std::{env, fs, path};
 
 use clap::Parser;
 use log::info;
@@ -140,6 +140,9 @@ impl<C: Circuit> Plonky2xFunction for C {
             AlgebraicHasher<InnerParameters::Field>,
         OuterParameters::Config: Serialize,
     {
+        // Setup enviroment variables.
+        env::set_var("BUILD_DIR", args.build_dir.clone());
+
         // If the request is of type bytes and the wrapper path is not empty, then we need to
         // start the gnark wrapper process.
         let gnark_wrapper_process = if let ProofRequest::Bytes(_) = request {
diff --git a/plonky2x/core/src/backend/prover/env.rs b/plonky2x/core/src/backend/prover/env.rs
index 894937bb8..c290b1fcb 100644
--- a/plonky2x/core/src/backend/prover/env.rs
+++ b/plonky2x/core/src/backend/prover/env.rs
@@ -32,7 +32,8 @@ impl EnvProver {
         } else {
             let gate_serializer = S::gate_registry::<L, D>();
             let generator_serializer = S::generator_registry::<L, D>();
-            let circuit_path = format!("./build/{}.circuit", circuit_id);
+            let build_dir = env::var("BUILD_DIR").unwrap_or_else(|_| "./build".to_string());
+            let circuit_path = format!("{}/{}.circuit", build_dir, circuit_id);
             let circuit =
                 CircuitBuild::<L, D>::load(&circuit_path, &gate_serializer, &generator_serializer)
                     .unwrap();
@@ -55,7 +56,8 @@ impl EnvProver {
         } else {
             let gate_serializer = S::gate_registry::<L, D>();
             let generator_serializer = S::generator_registry::<L, D>();
-            let circuit_path = format!("./build/{}.circuit", circuit_id);
+            let build_dir = env::var("BUILD_DIR").unwrap_or_else(|_| "./build".to_string());
+            let circuit_path = format!("{}/{}.circuit", build_dir, circuit_id);
             let circuit =
                 CircuitBuild::<L, D>::load(&circuit_path, &gate_serializer, &generator_serializer)
                     .unwrap();