diff --git a/executor/src/witgen/jit/block_machine_processor.rs b/executor/src/witgen/jit/block_machine_processor.rs
index ba307e93d2..0d447a1037 100644
--- a/executor/src/witgen/jit/block_machine_processor.rs
+++ b/executor/src/witgen/jit/block_machine_processor.rs
@@ -13,6 +13,7 @@ use crate::witgen::{
 
 use super::{
     processor::ProcessorResult,
+    prover_function_heuristics::ProverFunction,
     variable::{Cell, Variable},
     witgen_inference::{CanProcessCall, FixedEvaluator, WitgenInference},
 };
@@ -50,7 +51,7 @@ impl<'a, T: FieldElement> BlockMachineProcessor<'a, T> {
         can_process: impl CanProcessCall<T>,
         identity_id: u64,
         known_args: &BitVec,
-    ) -> Result<ProcessorResult<T>, String> {
+    ) -> Result<(ProcessorResult<T>, Vec<ProverFunction<'a>>), String> {
         let connection = self.machine_parts.connections[&identity_id];
         assert_eq!(connection.right.expressions.len(), known_args.len());
 
@@ -119,7 +120,7 @@ impl<'a, T: FieldElement> BlockMachineProcessor<'a, T> {
             .iter()
             .enumerate()
             .filter_map(|(i, is_input)| (!is_input).then_some(Variable::Param(i)));
-        Processor::new(
+        let result = Processor::new(
             self.fixed_data,
             self,
             identities,
@@ -154,7 +155,8 @@ impl<'a, T: FieldElement> BlockMachineProcessor<'a, T> {
                 .take(10)
                 .format("\n  ");
             format!("Code generation failed: {shortened_error}\nRun with RUST_LOG=trace to see the code generated so far.")
-        })
+        })?;
+        Ok((result, prover_functions))
     }
 }
 
@@ -243,7 +245,9 @@ mod test {
                 .chain((0..num_outputs).map(|_| false)),
         );
 
-        processor.generate_code(&mutable_state, connection_id, &known_values)
+        processor
+            .generate_code(&mutable_state, connection_id, &known_values)
+            .map(|(result, _)| result)
     }
 
     #[test]
diff --git a/executor/src/witgen/jit/compiler.rs b/executor/src/witgen/jit/compiler.rs
index ca90e7b23c..0e29b2a785 100644
--- a/executor/src/witgen/jit/compiler.rs
+++ b/executor/src/witgen/jit/compiler.rs
@@ -6,7 +6,7 @@ use powdr_ast::{
     analyzed::{PolyID, PolynomialType},
     indent,
 };
-use powdr_jit_compiler::util_code::util_code;
+use powdr_jit_compiler::{util_code::util_code, CodeGenerator, DefinitionFetcher};
 use powdr_number::FieldElement;
 
 use crate::witgen::{
@@ -14,6 +14,7 @@ use crate::witgen::{
         finalizable_data::{ColumnLayout, CompactDataRef},
         mutable_state::MutableState,
     },
+    jit::prover_function_heuristics::ProverFunctionComputation,
     machines::{
         profiling::{record_end, record_start},
         LookupCell,
@@ -23,6 +24,7 @@ use crate::witgen::{
 
 use super::{
     effect::{Assertion, BranchCondition, Effect, ProverFunctionCall},
+    prover_function_heuristics::ProverFunction,
     symbolic_expression::{BinaryOperator, BitOperator, SymbolicExpression, UnaryOperator},
     variable::Variable,
 };
@@ -87,17 +89,30 @@ extern "C" fn call_machine<T: FieldElement, Q: QueryCallback<T>>(
 }
 
 /// Compile the given inferred effects into machine code and load it.
-pub fn compile_effects<T: FieldElement>(
+pub fn compile_effects<T: FieldElement, D: DefinitionFetcher>(
+    definitions: &D,
     column_layout: ColumnLayout,
     known_inputs: &[Variable],
     effects: &[Effect<T, Variable>],
+    prover_functions: Vec<ProverFunction<'_>>,
 ) -> Result<WitgenFunction<T>, String> {
     let utils = util_code::<T>()?;
     let interface = interface_code(column_layout);
+    let mut codegen = CodeGenerator::<T, _>::new(definitions);
+    let prover_functions = prover_functions
+        .iter()
+        .map(|f| prover_function_code(f, &mut codegen))
+        .collect::<Result<Vec<_>, _>>()?
+        .into_iter()
+        .format("\n");
+    let prover_functions_dependents = codegen.generated_code();
     let witgen_code = witgen_code(known_inputs, effects);
     let code = format!(
         "{utils}\n\
         //-------------------------------\n\
+        {prover_functions_dependents}\n\
+        {prover_functions}\n\
+        //-------------------------------\n\
         {interface}\n\
         //-------------------------------\n\
         {witgen_code}"
@@ -522,11 +537,35 @@ fn interface_code(column_layout: ColumnLayout) -> String {
     )
 }
 
+fn prover_function_code<T: FieldElement, D: DefinitionFetcher>(
+    f: &ProverFunction<'_>,
+    codegen: &mut CodeGenerator<'_, T, D>,
+) -> Result<String, String> {
+    let code = match f.computation {
+        ProverFunctionComputation::ComputeFrom(code) => format!(
+            "({}).call(args.to_vec().into())",
+            codegen.generate_code_for_expression(code)?
+        ),
+        ProverFunctionComputation::ProvideIfUnknown(code) => {
+            format!("({}).call()", codegen.generate_code_for_expression(code)?)
+        }
+    };
+
+    let index = f.index;
+    Ok(format!(
+        "fn prover_function_{index}(i: u64, args: &[FieldElement]) -> FieldElement {{\n\
+            let i: ibig::IBig = i.into();\n\
+            {code}
+        }}"
+    ))
+}
+
 #[cfg(test)]
 mod tests {
 
     use std::ptr::null;
 
+    use powdr_ast::analyzed::FunctionValueDefinition;
     use pretty_assertions::assert_eq;
     use test_log::test;
 
@@ -538,18 +577,27 @@ mod tests {
 
     use super::*;
 
+    struct NoDefinitions;
+    impl DefinitionFetcher for NoDefinitions {
+        fn get_definition(&self, _: &str) -> Option<&FunctionValueDefinition> {
+            None
+        }
+    }
+
     fn compile_effects(
         column_count: usize,
         known_inputs: &[Variable],
         effects: &[Effect<GoldilocksField, Variable>],
     ) -> Result<WitgenFunction<GoldilocksField>, String> {
         super::compile_effects(
+            &NoDefinitions,
             ColumnLayout {
                 column_count,
                 first_column_id: 0,
             },
             known_inputs,
             effects,
+            vec![],
         )
     }
 
diff --git a/executor/src/witgen/jit/function_cache.rs b/executor/src/witgen/jit/function_cache.rs
index 460c9ca1ca..eefb1d71fd 100644
--- a/executor/src/witgen/jit/function_cache.rs
+++ b/executor/src/witgen/jit/function_cache.rs
@@ -117,10 +117,13 @@ impl<'a, T: FieldElement> FunctionCache<'a, T> {
             cache_key.known_args
         );
 
-        let ProcessorResult {
-            code,
-            range_constraints,
-        } = self
+        let (
+            ProcessorResult {
+                code,
+                range_constraints,
+            },
+            prover_functions,
+        ) = self
             .processor
             .generate_code(can_process, cache_key.identity_id, &cache_key.known_args)
             .map_err(|e| {
@@ -177,7 +180,14 @@ impl<'a, T: FieldElement> FunctionCache<'a, T> {
             .collect::<Vec<_>>();
 
         log::trace!("Compiling effects...");
-        let function = compile_effects(self.column_layout.clone(), &known_inputs, &code).unwrap();
+        let function = compile_effects(
+            self.fixed_data.analyzed,
+            self.column_layout.clone(),
+            &known_inputs,
+            &code,
+            prover_functions,
+        )
+        .unwrap();
         log::trace!("Compilation done.");
 
         Some(CacheEntry {
diff --git a/executor/src/witgen/jit/interpreter.rs b/executor/src/witgen/jit/interpreter.rs
index fd26936c9e..58a83f8b83 100644
--- a/executor/src/witgen/jit/interpreter.rs
+++ b/executor/src/witgen/jit/interpreter.rs
@@ -533,15 +533,15 @@ mod test {
                 .chain((0..num_outputs).map(|_| false)),
         );
 
-        let effects = processor
+        // TODO we cannot compile the prover functions here, but we can evaluate them.
+        let (result, _prover_functions) = processor
             .generate_code(&mutable_state, connection_id, &known_values)
-            .unwrap()
-            .code;
+            .unwrap();
 
         let known_inputs = (0..12).map(Variable::Param).collect::<Vec<_>>();
 
         // generate interpreter
-        let interpreter = EffectsInterpreter::new(&known_inputs, &effects);
+        let interpreter = EffectsInterpreter::new(&known_inputs, &result.code);
         // call it
         let mut params = [GoldilocksField::default(); 16];
         let mut param_lookups = params
diff --git a/jit-compiler/src/codegen.rs b/jit-compiler/src/codegen.rs
index 7253d98963..cdb6db84d3 100644
--- a/jit-compiler/src/codegen.rs
+++ b/jit-compiler/src/codegen.rs
@@ -80,6 +80,13 @@ impl<'a, T: FieldElement, Def: DefinitionFetcher> CodeGenerator<'a, T, Def> {
         Ok(self.symbol_reference(name, type_args))
     }
 
+    /// Generates code for an isolated expression. This might request code generation
+    /// for referenced symbols, this the returned code is only valid code in connection with
+    /// the code returned by `self.generated_code`.
+    pub fn generate_code_for_expression(&mut self, e: &Expression) -> Result<String, String> {
+        self.format_expr(e, 0)
+    }
+
     /// Returns the concatenation of all successfully compiled symbols.
     pub fn generated_code(self) -> String {
         self.symbols
diff --git a/jit-compiler/src/lib.rs b/jit-compiler/src/lib.rs
index a97d778c84..2719356688 100644
--- a/jit-compiler/src/lib.rs
+++ b/jit-compiler/src/lib.rs
@@ -8,13 +8,13 @@ use std::{
     sync::Arc,
 };
 
-use codegen::CodeGenerator;
 use compiler::{generate_glue_code, load_library};
 
 use itertools::Itertools;
 use powdr_ast::analyzed::Analyzed;
 use powdr_number::FieldElement;
 
+pub use codegen::{CodeGenerator, DefinitionFetcher};
 pub use compiler::call_cargo;
 
 pub struct CompiledPIL {