diff --git a/Cargo.lock b/Cargo.lock
index b9d60342..12706516 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -235,13 +235,6 @@ dependencies = [
  "unicode-ident",
 ]
 
-[[package]]
-name = "program_builder"
-version = "0.1.0"
-dependencies = [
- "uplc",
-]
-
 [[package]]
 name = "quote"
 version = "1.0.18"
diff --git a/Cargo.toml b/Cargo.toml
index 0b391440..f409c5ce 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,2 +1,2 @@
 [workspace]
-members = ["crates/cli", "crates/flat", "crates/uplc", "crates/program_builder"]
+members = ["crates/cli", "crates/flat", "crates/uplc"]
diff --git a/crates/program_builder/Cargo.toml b/crates/program_builder/Cargo.toml
deleted file mode 100644
index e076f18a..00000000
--- a/crates/program_builder/Cargo.toml
+++ /dev/null
@@ -1,10 +0,0 @@
-[package]
-name = "program_builder"
-version = "0.1.0"
-edition = "2021"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-# 1st party
-uplc = { path = '../uplc', version = "0.0.5" }
diff --git a/crates/uplc/Cargo.toml b/crates/uplc/Cargo.toml
index e1a93b69..4a079719 100644
--- a/crates/uplc/Cargo.toml
+++ b/crates/uplc/Cargo.toml
@@ -18,3 +18,7 @@ hex = "0.4.3"
 peg = "0.8.0"
 pretty = "0.11.3"
 thiserror = "1.0.31"
+
+[features]
+unstable = []
+test = ["unstable"]
diff --git a/crates/uplc/src/lib.rs b/crates/uplc/src/lib.rs
index fd3b4c31..e13a58ad 100644
--- a/crates/uplc/src/lib.rs
+++ b/crates/uplc/src/lib.rs
@@ -5,5 +5,5 @@ mod flat;
 pub mod parser;
 mod pretty;
 
-#[cfg(test)]
-mod test;
+#[cfg(any(feature = "unstable", test))]
+pub mod program_builder;
diff --git a/crates/program_builder/src/lib.rs b/crates/uplc/src/program_builder.rs
similarity index 97%
rename from crates/program_builder/src/lib.rs
rename to crates/uplc/src/program_builder.rs
index c9336619..688ed3c0 100644
--- a/crates/program_builder/src/lib.rs
+++ b/crates/uplc/src/program_builder.rs
@@ -1,8 +1,8 @@
 #![cfg_attr(test, allow(non_snake_case))]
 
+use crate::ast::{Constant, Name, Program, Term, Unique};
 use std::cell::{Cell, RefCell};
 use std::collections::HashMap;
-use uplc::ast::{Constant, Name, Program, Term, Unique};
 
 #[cfg(test)]
 mod tests;
diff --git a/crates/program_builder/src/tests.rs b/crates/uplc/src/program_builder/tests.rs
similarity index 97%
rename from crates/program_builder/src/tests.rs
rename to crates/uplc/src/program_builder/tests.rs
index d2be8415..22e2acfb 100644
--- a/crates/program_builder/src/tests.rs
+++ b/crates/uplc/src/program_builder/tests.rs
@@ -1,5 +1,5 @@
-use crate::{Builder, WithTerm};
-use uplc::parser;
+use super::*;
+use crate::parser;
 
 #[test]
 fn build_named__with_const() {
diff --git a/crates/uplc/src/test.rs b/crates/uplc/src/test.rs
deleted file mode 100644
index ae5f3f1f..00000000
--- a/crates/uplc/src/test.rs
+++ /dev/null
@@ -1,57 +0,0 @@
-/// e2e encoding/decoding tests
-use crate::{
-    ast::{DeBruijn, Name, Program},
-    parser,
-};
-
-#[test]
-fn integer() {
-    let bytes = include_bytes!("../test_data/basic/integer/integer.flat");
-    let code = include_str!("../test_data/basic/integer/integer.uplc");
-
-    let parsed_program = parser::program(code).unwrap();
-
-    let debruijn_program: Program<DeBruijn> = parsed_program.clone().try_into().unwrap();
-
-    let decoded_program: Program<DeBruijn> = Program::from_flat(bytes).unwrap();
-
-    assert_eq!(debruijn_program, decoded_program);
-
-    let encoded_program = debruijn_program.to_flat().unwrap();
-
-    assert_eq!(encoded_program, bytes);
-
-    let name_program: Program<Name> = decoded_program.try_into().unwrap();
-
-    assert_eq!(parsed_program, name_program);
-
-    let pretty = name_program.to_pretty();
-
-    assert_eq!(pretty, code);
-}
-
-#[test]
-fn jpg() {
-    let bytes = include_bytes!("../test_data/jpg/jpg.flat");
-    let code = include_str!("../test_data/jpg/jpg.uplc");
-
-    let parsed_program = parser::program(code).unwrap();
-
-    let debruijn_program: Program<DeBruijn> = parsed_program.clone().try_into().unwrap();
-
-    let decoded_program: Program<DeBruijn> = Program::from_flat(bytes).unwrap();
-
-    assert_eq!(debruijn_program, decoded_program);
-
-    let encoded_program = debruijn_program.to_flat().unwrap();
-
-    assert_eq!(encoded_program, bytes);
-
-    let name_program: Program<Name> = decoded_program.try_into().unwrap();
-
-    assert_eq!(parsed_program, name_program);
-
-    let pretty = name_program.to_pretty();
-
-    assert_eq!(pretty, code);
-}
diff --git a/crates/uplc/tests/integ_tests.rs b/crates/uplc/tests/integ_tests.rs
index e6bf60fa..753e73c0 100644
--- a/crates/uplc/tests/integ_tests.rs
+++ b/crates/uplc/tests/integ_tests.rs
@@ -74,7 +74,6 @@ fn fibonacci() {
     round_trip_test(bytes, code);
 }
 
-// TODO: This is failing, see Bug: https://github.com/txpipe/aiken/issues/10
 #[test]
 fn one_way_fibonacci() {
     let bytes = include_bytes!("../test_data/fibonacci/fibonacci.flat");