diff --git a/src/interface/ffi/src/main.zig b/src/interface/ffi/src/main.zig
index edc0af8..250cf88 100644
--- a/src/interface/ffi/src/main.zig
+++ b/src/interface/ffi/src/main.zig
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright (c) 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
+//
 // Julianiser FFI Implementation
 //
 // Implements the C-compatible FFI declared in src/interface/abi/Foreign.idr.
diff --git a/src/lib.rs b/src/lib.rs
index a26e736..56cc5f7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright (c) 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
+
 #![allow(
     dead_code,
     clippy::too_many_arguments,
diff --git a/src/main.rs b/src/main.rs
index e5b2f21..93e7b96 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright (c) 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
+
 #![allow(
     dead_code,
     clippy::too_many_arguments,