diff --git a/Cargo.toml b/Cargo.toml
index 4dd959cd..c577ffcf 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,5 +1,4 @@
 [features]
-mpi = ["dep:mpi", "ndelement/mpi", "ndgrid/mpi"]
 sleef = ["rlst/sleef", "green-kernels/sleef", "ndelement/sleef", "ndgrid/sleef"]
 strict = []
 default = ["sleef"]
@@ -28,13 +27,13 @@ crate-type = ["lib", "cdylib"]
 [dependencies]
 bempp-quadrature = { version = "0.1.0" }
 itertools = "0.13.*"
-mpi = { version = "0.8.*", optional = true }
+mpi = { version = "0.8.*"}
 num = "0.4"
-ndelement = { git="https://github.com/bempp/ndelement.git", default-features = false }
-ndgrid = { git="https://github.com/bempp/ndgrid.git", default-features = false }
+ndelement = { git="https://github.com/bempp/ndelement.git", features = ["mpi"]}
+ndgrid = { git="https://github.com/bempp/ndgrid.git", features = ["mpi"] }
 rayon = "1.9"
-rlst = { git = "https://github.com/linalg-rs/rlst.git", default-features = false }
-green-kernels = { git = "https://github.com/bempp/green-kernels.git", default-features = false }
+rlst = { git = "https://github.com/linalg-rs/rlst.git", features = ["mpi"] }
+green-kernels = { git = "https://github.com/bempp/green-kernels.git", features = ["mpi"] }
 c-api-tools = { version = "0.1.0" }
 
 [dev-dependencies]
diff --git a/examples/test_parallel_assembly.rs b/examples/test_parallel_assembly.rs
index ed6f7cae..8c184af3 100644
--- a/examples/test_parallel_assembly.rs
+++ b/examples/test_parallel_assembly.rs
@@ -1,39 +1,30 @@
 //? mpirun -n {{NPROCESSES}} --features "mpi"
 
-#[cfg(feature = "mpi")]
 use approx::assert_relative_eq;
-#[cfg(feature = "mpi")]
 use bempp::{
     boundary_assemblers::BoundaryAssemblerOptions,
     function::{FunctionSpace, ParallelFunctionSpace, SerialFunctionSpace},
     laplace,
 };
-#[cfg(feature = "mpi")]
 use itertools::izip;
-#[cfg(feature = "mpi")]
 use mpi::{
     collective::CommunicatorCollectives,
     environment::Universe,
     request::WaitGuard,
     traits::{Communicator, Destination, Source},
 };
-#[cfg(feature = "mpi")]
 use ndelement::{
     ciarlet::{CiarletElement, LagrangeElementFamily},
     types::{Continuity, ReferenceCellType},
 };
-#[cfg(feature = "mpi")]
 use ndgrid::{
     grid::parallel::ParallelGrid,
     traits::{Builder, Entity, Grid, ParallelBuilder},
     SingleElementGrid, SingleElementGridBuilder,
 };
-#[cfg(feature = "mpi")]
 use rlst::{CsrMatrix, Shape};
-#[cfg(feature = "mpi")]
 use std::collections::{hash_map::Entry, HashMap};
 
-#[cfg(feature = "mpi")]
 fn create_single_element_grid_data(b: &mut SingleElementGridBuilder<f64>, n: usize) {
     for y in 0..n {
         for x in 0..n {
@@ -54,7 +45,6 @@ fn create_single_element_grid_data(b: &mut SingleElementGridBuilder<f64>, n: usi
     }
 }
 
-#[cfg(feature = "mpi")]
 fn example_single_element_grid<C: Communicator>(
     comm: &C,
     n: usize,
@@ -71,14 +61,12 @@ fn example_single_element_grid<C: Communicator>(
     }
 }
 
-#[cfg(feature = "mpi")]
 fn example_single_element_grid_serial(n: usize) -> SingleElementGrid<f64, CiarletElement<f64>> {
     let mut b = SingleElementGridBuilder::<f64>::new(3, (ReferenceCellType::Quadrilateral, 1));
     create_single_element_grid_data(&mut b, n);
     b.create_grid()
 }
 
-#[cfg(feature = "mpi")]
 fn test_parallel_assembly_single_element_grid<C: Communicator>(
     comm: &C,
     degree: usize,
@@ -231,7 +219,6 @@ fn test_parallel_assembly_single_element_grid<C: Communicator>(
     }
 }
 
-#[cfg(feature = "mpi")]
 fn main() {
     let universe: Universe = mpi::initialize().unwrap();
     let world = universe.world();
@@ -252,6 +239,3 @@ fn main() {
         world.barrier();
     }
 }
-
-#[cfg(not(feature = "mpi"))]
-fn main() {}
diff --git a/src/boundary_evaluators.rs b/src/boundary_evaluators.rs
new file mode 100644
index 00000000..e69de29b
diff --git a/src/function.rs b/src/function.rs
index 65c8666d..5a1bd283 100644
--- a/src/function.rs
+++ b/src/function.rs
@@ -2,11 +2,9 @@
 
 mod function_space;
 
-#[cfg(feature = "mpi")]
 pub use function_space::ParallelFunctionSpace;
 pub use function_space::SerialFunctionSpace;
 
-#[cfg(feature = "mpi")]
 use mpi::traits::Communicator;
 use ndelement::{traits::FiniteElement, types::ReferenceCellType};
 use ndgrid::{traits::Grid, types::Ownership};
@@ -66,7 +64,6 @@ pub trait FunctionSpace {
     fn ownership(&self, local_dof_index: usize) -> Ownership;
 }
 
-#[cfg(feature = "mpi")]
 /// A function space in parallel
 pub trait MPIFunctionSpace<C: Communicator>: FunctionSpace {
     /// MPI communicator
diff --git a/src/function/function_space.rs b/src/function/function_space.rs
index 9f6f2d66..22f3e9e5 100644
--- a/src/function/function_space.rs
+++ b/src/function/function_space.rs
@@ -1,11 +1,9 @@
 //! Function space
 
 mod common;
-#[cfg(feature = "mpi")]
 mod parallel;
 mod serial;
 
 use common::assign_dofs;
-#[cfg(feature = "mpi")]
 pub use parallel::ParallelFunctionSpace;
 pub use serial::SerialFunctionSpace;