diff --git a/crates/uplc/src/ast.rs b/crates/uplc/src/ast.rs
index f303eacf..8e40b22d 100644
--- a/crates/uplc/src/ast.rs
+++ b/crates/uplc/src/ast.rs
@@ -374,3 +374,14 @@ impl From<Term<FakeNamedDeBruijn>> for Term<NamedDeBruijn> {
         converter.fake_named_debruijn_to_named_debruijn(value)
     }
 }
+
+pub fn apply_program<T>(p1: Program<T>, p2: Program<T>) -> Program<T> {
+    let applied_term = Term::Apply {
+        function: Box::new(p1.term),
+        argument: Box::new(p2.term),
+    };
+    Program {
+        version: p1.version,
+        term: applied_term,
+    }
+}
diff --git a/crates/uplc/src/interpreter.rs b/crates/uplc/src/interpreter.rs
new file mode 100644
index 00000000..3e109624
--- /dev/null
+++ b/crates/uplc/src/interpreter.rs
@@ -0,0 +1,110 @@
+use crate::{
+    ast::{Constant, NamedDeBruijn, Term},
+    builtins::DefaultFunction,
+};
+
+enum StepKind {
+    BConst = 0,
+    BVar = 1,
+    BLamAbs = 2,
+    BApply = 3,
+    BDelay = 4,
+    BForce = 5,
+    BBuiltin = 6,
+}
+
+enum ExBudgetCategory {
+    BStep(StepKind),
+    BBuiltinApp(DefaultFunction),
+    BStartup,
+}
+/// Can be negative
+#[derive(Debug, Clone, PartialEq)]
+struct ExBudget {
+    mem: i32,
+    cpu: i32,
+}
+
+enum CekValue {
+    VCon(Constant),
+    VDelay(Term<NamedDeBruijn>, Vec<CekValue>),
+    VLamAbs(NamedDeBruijn, Term<NamedDeBruijn>, Vec<CekValue>),
+    VBuiltin(
+        DefaultFunction,
+        Term<NamedDeBruijn>,
+        // Need to figure out run time stuff
+        // BuiltinRuntime (CekValue uni fun)
+    ),
+}
+
+enum Context {
+    FrameApplyFun(Term<NamedDeBruijn>, Term<NamedDeBruijn>),
+    FrameApplyArg(Vec<CekValue>, Term<NamedDeBruijn>, Box<Context>),
+    FrameForce(Box<Context>),
+    NoFrame,
+}
+
+// For now let's just start with running cek on term with generic params
+fn run_cek_debruijn(term: Term<NamedDeBruijn>) -> (Term<NamedDeBruijn>, usize, Vec<String>) {
+    //paramerterize this
+    let initial_budget = ExBudget {
+        mem: 1000,
+        cpu: 1000,
+    };
+
+    let evaluation = enter_compute_cek(Context::NoFrame, Vec::new(), term);
+    todo!()
+}
+
+fn spend_budget_cek(
+    current_budget: ExBudget,
+    category: ExBudgetCategory,
+    spend_budget: ExBudget,
+) -> ExBudget {
+    let new_budget = ExBudget {
+        mem: current_budget.mem - spend_budget.mem,
+        cpu: current_budget.cpu - spend_budget.cpu,
+    };
+    if new_budget.mem < 0 || new_budget.cpu < 0 {
+        panic!("Budget exhausted {:?}", new_budget);
+    }
+    new_budget
+}
+
+fn enter_compute_cek(
+    frame: Context,
+    env: Vec<CekValue>,
+    term: Term<NamedDeBruijn>,
+) -> (Term<NamedDeBruijn>, usize, Vec<u32>) {
+    //enter compute
+    compute_cek(Vec::with_capacity(8), frame, env, term)
+}
+
+fn compute_cek(
+    mut unbudgeted_steps: Vec<u32>,
+    frame: Context,
+    env: Vec<CekValue>,
+    term: Term<NamedDeBruijn>,
+) -> (Term<NamedDeBruijn>, usize, Vec<u32>) {
+    //TODO: parameterize slippage
+    let slippage = 200;
+    match (term) {
+        a @ Term::Var(_) => {
+            unbudgeted_steps[2] += 1;
+            unbudgeted_steps[7] += 1;
+            //TODO spend budget one slippage is met
+            todo!()
+        }
+        Term::Delay(_) => todo!(),
+        Term::Lambda {
+            parameter_name,
+            body,
+        } => todo!(),
+        Term::Apply { function, argument } => todo!(),
+        Term::Constant(_) => todo!(),
+        Term::Force(_) => todo!(),
+        Term::Error => todo!(),
+        Term::Builtin(_) => todo!(),
+    }
+}
+
diff --git a/crates/uplc/src/lib.rs b/crates/uplc/src/lib.rs
index 6d22da98..f6512702 100644
--- a/crates/uplc/src/lib.rs
+++ b/crates/uplc/src/lib.rs
@@ -2,6 +2,7 @@ pub mod ast;
 pub mod builtins;
 mod debruijn;
 mod flat;
+pub mod interpreter;
 pub mod parser;
 mod pretty;
 pub mod program_builder;