diff --git a/codegen_scripts/cleangenerated.sh b/codegen_scripts/cleangenerated.sh
index 9f2651c..e1d951a 100755
--- a/codegen_scripts/cleangenerated.sh
+++ b/codegen_scripts/cleangenerated.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # Remove backups of generated code.
 # Also remove the temporary file that generated code is written to.
diff --git a/codegen_scripts/cpgenerated.sh b/codegen_scripts/cpgenerated.sh
index c12f454..f159912 100755
--- a/codegen_scripts/cpgenerated.sh
+++ b/codegen_scripts/cpgenerated.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # For generated.rs
 # Copy the generated code from the temporary files to which it is written
diff --git a/codegen_scripts/cpnodes.sh b/codegen_scripts/cpnodes.sh
index e43bac4..0176714 100755
--- a/codegen_scripts/cpnodes.sh
+++ b/codegen_scripts/cpnodes.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # For nodes.rs
 # Copy the generated code from the temporary files to which it is written
diff --git a/codegen_scripts/mk_nodes.sh b/codegen_scripts/mk_nodes.sh
index ced2420..838d155 100755
--- a/codegen_scripts/mk_nodes.sh
+++ b/codegen_scripts/mk_nodes.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # See mkgenerated.sh
 
diff --git a/codegen_scripts/mk_syntax_kinds.sh b/codegen_scripts/mk_syntax_kinds.sh
index 56f2915..e3b2764 100755
--- a/codegen_scripts/mk_syntax_kinds.sh
+++ b/codegen_scripts/mk_syntax_kinds.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # See mkgenerated.sh
 
diff --git a/codegen_scripts/mk_syntax_tokens.sh b/codegen_scripts/mk_syntax_tokens.sh
index 0b17b8c..34baee7 100755
--- a/codegen_scripts/mk_syntax_tokens.sh
+++ b/codegen_scripts/mk_syntax_tokens.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # See mkgenerated.sh
 
diff --git a/codegen_scripts/mkgenerated.sh b/codegen_scripts/mkgenerated.sh
index 8f4ca2f..1fd603d 100755
--- a/codegen_scripts/mkgenerated.sh
+++ b/codegen_scripts/mkgenerated.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # This is not how r-a does generation.
 # But I find a boot strapping problem.
diff --git a/crates/lexer/src/cursor.rs b/crates/lexer/src/cursor.rs
index 3c52dca..5530b07 100644
--- a/crates/lexer/src/cursor.rs
+++ b/crates/lexer/src/cursor.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use std::str::Chars;
 
diff --git a/crates/lexer/src/lib.rs b/crates/lexer/src/lib.rs
index 5dab052..fdf3359 100644
--- a/crates/lexer/src/lib.rs
+++ b/crates/lexer/src/lib.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Low-level OpenQASM3 lexer.
 //!
diff --git a/crates/lexer/src/tests.rs b/crates/lexer/src/tests.rs
index b2670a7..2f9b094 100644
--- a/crates/lexer/src/tests.rs
+++ b/crates/lexer/src/tests.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use super::*;
 
diff --git a/crates/lexer/src/unescape.rs b/crates/lexer/src/unescape.rs
index cb834c6..c45d0b9 100644
--- a/crates/lexer/src/unescape.rs
+++ b/crates/lexer/src/unescape.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Utilities for validating string and char literals and turning them into
 //! values they represent.
diff --git a/crates/lexer/src/unescape/tests.rs b/crates/lexer/src/unescape/tests.rs
index 39189fe..50e4fa1 100644
--- a/crates/lexer/src/unescape/tests.rs
+++ b/crates/lexer/src/unescape/tests.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use super::*;
 
diff --git a/crates/oq3_syntax/examples/demotest.rs b/crates/oq3_syntax/examples/demotest.rs
index 3709336..697afd0 100644
--- a/crates/oq3_syntax/examples/demotest.rs
+++ b/crates/oq3_syntax/examples/demotest.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use clap::{Parser, Subcommand};
 use std::fs;
diff --git a/crates/oq3_syntax/examples/itemparse.rs b/crates/oq3_syntax/examples/itemparse.rs
index 1e3113d..b223b0d 100644
--- a/crates/oq3_syntax/examples/itemparse.rs
+++ b/crates/oq3_syntax/examples/itemparse.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use ast::{HasModuleItem, HasName};
 use oq3_syntax::ast;
diff --git a/crates/oq3_syntax/examples/promote.rs b/crates/oq3_syntax/examples/promote.rs
index dacc863..7f26181 100644
--- a/crates/oq3_syntax/examples/promote.rs
+++ b/crates/oq3_syntax/examples/promote.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 // Test validating types of arguments to binary ops. That is test if they are legal.
 // And compute the common type that they must be promoted to.
diff --git a/crates/oq3_syntax/src/ast.rs b/crates/oq3_syntax/src/ast.rs
index 3b58881..55931e2 100644
--- a/crates/oq3_syntax/src/ast.rs
+++ b/crates/oq3_syntax/src/ast.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Abstract Syntax Tree, layered on top of untyped `SyntaxNode`s
 
diff --git a/crates/oq3_syntax/src/ast/edit.rs b/crates/oq3_syntax/src/ast/edit.rs
index b783c22..5a71d91 100644
--- a/crates/oq3_syntax/src/ast/edit.rs
+++ b/crates/oq3_syntax/src/ast/edit.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This module contains functions for editing syntax trees. As the trees are
 //! immutable, all function here return a fresh copy of the tree, instead of
diff --git a/crates/oq3_syntax/src/ast/expr_ext.rs b/crates/oq3_syntax/src/ast/expr_ext.rs
index 577bb54..f805c47 100644
--- a/crates/oq3_syntax/src/ast/expr_ext.rs
+++ b/crates/oq3_syntax/src/ast/expr_ext.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Various extension methods to ast Expr Nodes, which are hard to code-generate.
 //!
diff --git a/crates/oq3_syntax/src/ast/generated.rs b/crates/oq3_syntax/src/ast/generated.rs
index 0b29601..647f557 100644
--- a/crates/oq3_syntax/src/ast/generated.rs
+++ b/crates/oq3_syntax/src/ast/generated.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This file is actually hand-written, but the submodules are indeed generated.
 #[rustfmt::skip]
diff --git a/crates/oq3_syntax/src/ast/generated/nodes.rs b/crates/oq3_syntax/src/ast/generated/nodes.rs
index 59926e5..636a3e2 100644
--- a/crates/oq3_syntax/src/ast/generated/nodes.rs
+++ b/crates/oq3_syntax/src/ast/generated/nodes.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Generated by `sourcegen_ast`, do not edit by hand.
 
diff --git a/crates/oq3_syntax/src/ast/generated/tokens.rs b/crates/oq3_syntax/src/ast/generated/tokens.rs
index 7f6c13d..d117999 100644
--- a/crates/oq3_syntax/src/ast/generated/tokens.rs
+++ b/crates/oq3_syntax/src/ast/generated/tokens.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Generated by `sourcegen_ast`, do not edit by hand.
 
diff --git a/crates/oq3_syntax/src/ast/make.rs b/crates/oq3_syntax/src/ast/make.rs
index ebe48a3..160b54a 100644
--- a/crates/oq3_syntax/src/ast/make.rs
+++ b/crates/oq3_syntax/src/ast/make.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This module contains free-standing functions for creating AST fragments out
 //! of smaller pieces.
diff --git a/crates/oq3_syntax/src/ast/node_ext.rs b/crates/oq3_syntax/src/ast/node_ext.rs
index 81e2c6e..e0299b0 100644
--- a/crates/oq3_syntax/src/ast/node_ext.rs
+++ b/crates/oq3_syntax/src/ast/node_ext.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Various extension methods to ast Nodes, which are hard to code-generate.
 //! Extensions for various expressions live in a sibling `expr_extensions` module.
diff --git a/crates/oq3_syntax/src/ast/operators.rs b/crates/oq3_syntax/src/ast/operators.rs
index 135bb91..f42e28b 100644
--- a/crates/oq3_syntax/src/ast/operators.rs
+++ b/crates/oq3_syntax/src/ast/operators.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Defines a bunch of data-less enums for unary and binary operators.
 //!
diff --git a/crates/oq3_syntax/src/ast/prec.rs b/crates/oq3_syntax/src/ast/prec.rs
index f7a2dc8..75ce18b 100644
--- a/crates/oq3_syntax/src/ast/prec.rs
+++ b/crates/oq3_syntax/src/ast/prec.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Precedence representation.
 
diff --git a/crates/oq3_syntax/src/ast/token_ext.rs b/crates/oq3_syntax/src/ast/token_ext.rs
index 4930858..5bf4e97 100644
--- a/crates/oq3_syntax/src/ast/token_ext.rs
+++ b/crates/oq3_syntax/src/ast/token_ext.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! There are many AstNodes, but only a few tokens, so we hand-write them here.
 //! I assume "them" refers to tokens (GJL AUG 2023)
diff --git a/crates/oq3_syntax/src/ast/traits.rs b/crates/oq3_syntax/src/ast/traits.rs
index 4c4518b..2604c8d 100644
--- a/crates/oq3_syntax/src/ast/traits.rs
+++ b/crates/oq3_syntax/src/ast/traits.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Various traits that are implemented by ast nodes.
 //!
diff --git a/crates/oq3_syntax/src/ast/type_ext.rs b/crates/oq3_syntax/src/ast/type_ext.rs
index 454b1bc..c527aac 100644
--- a/crates/oq3_syntax/src/ast/type_ext.rs
+++ b/crates/oq3_syntax/src/ast/type_ext.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use crate::{ast, SyntaxToken, T};
 
diff --git a/crates/oq3_syntax/src/lib.rs b/crates/oq3_syntax/src/lib.rs
index 566f25e..d949834 100644
--- a/crates/oq3_syntax/src/lib.rs
+++ b/crates/oq3_syntax/src/lib.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Syntax Tree library used throughout the rust-analyzer.
 //!
diff --git a/crates/oq3_syntax/src/parsing.rs b/crates/oq3_syntax/src/parsing.rs
index 42b42e4..d4f77f5 100644
--- a/crates/oq3_syntax/src/parsing.rs
+++ b/crates/oq3_syntax/src/parsing.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Lexing, bridging to parser (which does the actual parsing) and
 //! incremental reparsing.
diff --git a/crates/oq3_syntax/src/ptr.rs b/crates/oq3_syntax/src/ptr.rs
index 94aeb1a..5da617d 100644
--- a/crates/oq3_syntax/src/ptr.rs
+++ b/crates/oq3_syntax/src/ptr.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! In rust-analyzer, syntax trees are transient objects.
 //!
diff --git a/crates/oq3_syntax/src/syntax_error.rs b/crates/oq3_syntax/src/syntax_error.rs
index 8901bf1..b3699c1 100644
--- a/crates/oq3_syntax/src/syntax_error.rs
+++ b/crates/oq3_syntax/src/syntax_error.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! See docs for `SyntaxError`.
 
diff --git a/crates/oq3_syntax/src/syntax_node.rs b/crates/oq3_syntax/src/syntax_node.rs
index f8b4c46..2c38f02 100644
--- a/crates/oq3_syntax/src/syntax_node.rs
+++ b/crates/oq3_syntax/src/syntax_node.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This module defines Concrete Syntax Tree (CST), used by rust-analyzer.
 //!
diff --git a/crates/oq3_syntax/src/ted.rs b/crates/oq3_syntax/src/ted.rs
index ff08846..fbe000e 100644
--- a/crates/oq3_syntax/src/ted.rs
+++ b/crates/oq3_syntax/src/ted.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Primitive tree editor, ed for trees.
 //!
diff --git a/crates/oq3_syntax/src/tests.rs b/crates/oq3_syntax/src/tests.rs
index da9bd83..4f6c017 100644
--- a/crates/oq3_syntax/src/tests.rs
+++ b/crates/oq3_syntax/src/tests.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 #[cfg(not(feature = "in-rust-tree"))]
 mod ast_src;
diff --git a/crates/oq3_syntax/src/tests/ast_src.rs b/crates/oq3_syntax/src/tests/ast_src.rs
index 8c74425..0d14ad8 100644
--- a/crates/oq3_syntax/src/tests/ast_src.rs
+++ b/crates/oq3_syntax/src/tests/ast_src.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Defines input for code generation process.
 
diff --git a/crates/oq3_syntax/src/tests/sourcegen_ast.rs b/crates/oq3_syntax/src/tests/sourcegen_ast.rs
index 7350956..b3d4179 100644
--- a/crates/oq3_syntax/src/tests/sourcegen_ast.rs
+++ b/crates/oq3_syntax/src/tests/sourcegen_ast.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This module generates AST datatype used by rust-analyzer. FIXME
 //!
diff --git a/crates/oq3_syntax/src/token_text.rs b/crates/oq3_syntax/src/token_text.rs
index 6b8e8ff..0577db7 100644
--- a/crates/oq3_syntax/src/token_text.rs
+++ b/crates/oq3_syntax/src/token_text.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Yet another version of owned string, backed by a syntax tree token.
 
diff --git a/crates/oq3_syntax/src/validation.rs b/crates/oq3_syntax/src/validation.rs
index dd60a71..60b6782 100644
--- a/crates/oq3_syntax/src/validation.rs
+++ b/crates/oq3_syntax/src/validation.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This module implements syntax validation that the parser doesn't handle.
 //!
diff --git a/crates/oq3_syntax/src/validation/block.rs b/crates/oq3_syntax/src/validation/block.rs
index 8b788d4..32e5e8c 100644
--- a/crates/oq3_syntax/src/validation/block.rs
+++ b/crates/oq3_syntax/src/validation/block.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Logic for validating block expressions i.e. `ast::BlockExpr`.
 
diff --git a/crates/parser/src/event.rs b/crates/parser/src/event.rs
index b5a441f..3c6378b 100644
--- a/crates/parser/src/event.rs
+++ b/crates/parser/src/event.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This module provides a way to construct a `File`.
 //! It is intended to be completely decoupled from the
diff --git a/crates/parser/src/grammar.rs b/crates/parser/src/grammar.rs
index b4ef204..42464c3 100644
--- a/crates/parser/src/grammar.rs
+++ b/crates/parser/src/grammar.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This is the actual "grammar" of the OpenQASM 3 language.
 //!
diff --git a/crates/parser/src/grammar/expressions.rs b/crates/parser/src/grammar/expressions.rs
index 79da403..fe51dfd 100644
--- a/crates/parser/src/grammar/expressions.rs
+++ b/crates/parser/src/grammar/expressions.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 pub mod atom;
 
diff --git a/crates/parser/src/grammar/expressions/atom.rs b/crates/parser/src/grammar/expressions/atom.rs
index 4bf3878..cf2b604 100644
--- a/crates/parser/src/grammar/expressions/atom.rs
+++ b/crates/parser/src/grammar/expressions/atom.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use super::*;
 
diff --git a/crates/parser/src/grammar/items.rs b/crates/parser/src/grammar/items.rs
index eac989e..718b0bc 100644
--- a/crates/parser/src/grammar/items.rs
+++ b/crates/parser/src/grammar/items.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use super::*;
 use crate::grammar::expressions::expr_block_contents;
diff --git a/crates/parser/src/grammar/params.rs b/crates/parser/src/grammar/params.rs
index 239b4b8..1a11d33 100644
--- a/crates/parser/src/grammar/params.rs
+++ b/crates/parser/src/grammar/params.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use super::*;
 
diff --git a/crates/parser/src/input.rs b/crates/parser/src/input.rs
index 11a0e02..7d0cd0e 100644
--- a/crates/parser/src/input.rs
+++ b/crates/parser/src/input.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! See [`Input`].
 
diff --git a/crates/parser/src/lexed_str.rs b/crates/parser/src/lexed_str.rs
index d87e052..4245527 100644
--- a/crates/parser/src/lexed_str.rs
+++ b/crates/parser/src/lexed_str.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Lexing `&str` into a sequence of OpenQASM 3 tokens.
 //!
diff --git a/crates/parser/src/lib.rs b/crates/parser/src/lib.rs
index f78d722..3d1a3cf 100644
--- a/crates/parser/src/lib.rs
+++ b/crates/parser/src/lib.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Parser for OpenQASM 3
 
diff --git a/crates/parser/src/output.rs b/crates/parser/src/output.rs
index 20ba869..d446c5c 100644
--- a/crates/parser/src/output.rs
+++ b/crates/parser/src/output.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! See [`Output`]
 
diff --git a/crates/parser/src/parser.rs b/crates/parser/src/parser.rs
index 194342a..b98063c 100644
--- a/crates/parser/src/parser.rs
+++ b/crates/parser/src/parser.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! See [`Parser`].
 
diff --git a/crates/parser/src/shortcuts.rs b/crates/parser/src/shortcuts.rs
index ad53319..7a09501 100644
--- a/crates/parser/src/shortcuts.rs
+++ b/crates/parser/src/shortcuts.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Shortcuts that span lexer/parser abstraction.
 //!
diff --git a/crates/parser/src/syntax_kind.rs b/crates/parser/src/syntax_kind.rs
index 9865a50..8cd3934 100644
--- a/crates/parser/src/syntax_kind.rs
+++ b/crates/parser/src/syntax_kind.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Defines [`SyntaxKind`] -- a fieldless enum of all possible syntactic
 //! constructs of the OpenQASM 3 language.
diff --git a/crates/parser/src/syntax_kind/syntax_kind_enum.rs b/crates/parser/src/syntax_kind/syntax_kind_enum.rs
index c78381f..02e19c3 100644
--- a/crates/parser/src/syntax_kind/syntax_kind_enum.rs
+++ b/crates/parser/src/syntax_kind/syntax_kind_enum.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Generated by `sourcegen_ast`, do not edit by hand.
 
diff --git a/crates/parser/src/token_set.rs b/crates/parser/src/token_set.rs
index c0fb463..c28fac7 100644
--- a/crates/parser/src/token_set.rs
+++ b/crates/parser/src/token_set.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! A bit-set of `SyntaxKind`s.
 
diff --git a/crates/semantics/examples/semdemo.rs b/crates/semantics/examples/semdemo.rs
index 3c99a68..3afa3b4 100644
--- a/crates/semantics/examples/semdemo.rs
+++ b/crates/semantics/examples/semdemo.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use clap::{Parser, Subcommand};
 use std::fs;
diff --git a/crates/semantics/src/asg.rs b/crates/semantics/src/asg.rs
index 7371f1c..66e0c92 100644
--- a/crates/semantics/src/asg.rs
+++ b/crates/semantics/src/asg.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 // The definition of the abstract semantic graph (ASG) as well as the API for using it.
 // Construction of this typed ASG from syntactic AST is in string_to_semantic.rs.
diff --git a/crates/semantics/src/context.rs b/crates/semantics/src/context.rs
index e68cd4d..792a728 100644
--- a/crates/semantics/src/context.rs
+++ b/crates/semantics/src/context.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use crate::asg;
 use crate::semantic_error::SemanticErrorKind::*;
diff --git a/crates/semantics/src/display.rs b/crates/semantics/src/display.rs
index 2ad6fd4..62c29d0 100644
--- a/crates/semantics/src/display.rs
+++ b/crates/semantics/src/display.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 // Unused at the moment.
 // This intent here is to print something like source code.
diff --git a/crates/semantics/src/initialize_ast.rs b/crates/semantics/src/initialize_ast.rs
index 2355299..3289bae 100644
--- a/crates/semantics/src/initialize_ast.rs
+++ b/crates/semantics/src/initialize_ast.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use crate::asg;
 use crate::symbols;
diff --git a/crates/semantics/src/lib.rs b/crates/semantics/src/lib.rs
index f6184ce..3a538e0 100644
--- a/crates/semantics/src/lib.rs
+++ b/crates/semantics/src/lib.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Abstract Semantic Graph (ASG)
 //! This crate implements an abstract semantic graph (ASG) for the OpenQASM 3 language.
diff --git a/crates/semantics/src/semantic_error.rs b/crates/semantics/src/semantic_error.rs
index 18279f2..0caac08 100644
--- a/crates/semantics/src/semantic_error.rs
+++ b/crates/semantics/src/semantic_error.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 // This is copied and modified from rust-analyzer syntax_error.rs
 use oq3_syntax::AstNode;
diff --git a/crates/semantics/src/symbols.rs b/crates/semantics/src/symbols.rs
index c7af62d..e4615be 100644
--- a/crates/semantics/src/symbols.rs
+++ b/crates/semantics/src/symbols.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 // Defines data structures and api for symbols, scope, and symbol tables.
 
diff --git a/crates/semantics/src/syntax_to_semantics.rs b/crates/semantics/src/syntax_to_semantics.rs
index b54f2ab..582174e 100644
--- a/crates/semantics/src/syntax_to_semantics.rs
+++ b/crates/semantics/src/syntax_to_semantics.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 // Build the ASG defined in asg.rs from the syntactic AST
 // constructed in the crate oq3_syntax.
diff --git a/crates/semantics/src/types.rs b/crates/semantics/src/types.rs
index dee48d5..bae069b 100644
--- a/crates/semantics/src/types.rs
+++ b/crates/semantics/src/types.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 // Defines the data structures representing the types used to annotate types of expressions in
 // the typed ASG.
diff --git a/crates/semantics/src/utils.rs b/crates/semantics/src/utils.rs
index 5ca7bba..8623b52 100644
--- a/crates/semantics/src/utils.rs
+++ b/crates/semantics/src/utils.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 /// Return the name of the type of a value.
 pub fn type_name_of<T>(_: T) -> &'static str {
diff --git a/crates/semantics/src/validate.rs b/crates/semantics/src/validate.rs
index 7bd4214..2d23cda 100644
--- a/crates/semantics/src/validate.rs
+++ b/crates/semantics/src/validate.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use crate::asg::{Expr, Program, Stmt, TExpr};
 use crate::symbols::{SymbolIdResult, SymbolTable};
diff --git a/crates/semantics/tests/ast_tests.rs b/crates/semantics/tests/ast_tests.rs
index edb60ea..a94841c 100644
--- a/crates/semantics/tests/ast_tests.rs
+++ b/crates/semantics/tests/ast_tests.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use semantics;
 use semantics::asg;
diff --git a/crates/semantics/tests/from_string_tests.rs b/crates/semantics/tests/from_string_tests.rs
index 937d482..39cf0ab 100644
--- a/crates/semantics/tests/from_string_tests.rs
+++ b/crates/semantics/tests/from_string_tests.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use semantics::asg;
 use semantics::semantic_error::SemanticErrorList;
diff --git a/crates/semantics/tests/symbol_tests.rs b/crates/semantics/tests/symbol_tests.rs
index 2f611ed..189c6c7 100644
--- a/crates/semantics/tests/symbol_tests.rs
+++ b/crates/semantics/tests/symbol_tests.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use semantics::symbols;
 use semantics::types;
diff --git a/crates/semantics/tests/types_test.rs b/crates/semantics/tests/types_test.rs
index e6be300..bb82fcd 100644
--- a/crates/semantics/tests/types_test.rs
+++ b/crates/semantics/tests/types_test.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use semantics::types;
 
diff --git a/crates/source_file/src/api.rs b/crates/source_file/src/api.rs
index 2f178ac..acbc191 100644
--- a/crates/source_file/src/api.rs
+++ b/crates/source_file/src/api.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 // It might be nice to put these functions in lib.rs.
 // But they are also used in this crate, so we put them here.
diff --git a/crates/source_file/src/lib.rs b/crates/source_file/src/lib.rs
index 1f8c2fb..3c4491b 100644
--- a/crates/source_file/src/lib.rs
+++ b/crates/source_file/src/lib.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! Management of source files for OpenQASM 3 parsing and semantic analysis.  The main `struct` here
 //! is `SourceFile` which contains the path to a source file and the AST produced by the parser. It
diff --git a/crates/source_file/src/source_file.rs b/crates/source_file/src/source_file.rs
index 3552ec7..393cc08 100644
--- a/crates/source_file/src/source_file.rs
+++ b/crates/source_file/src/source_file.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 use oq3_syntax::ast as synast; // Syntactic AST
 use oq3_syntax::Parse;
diff --git a/crates/sourcegen/src/lib.rs b/crates/sourcegen/src/lib.rs
index d48fbbc..1916bc8 100644
--- a/crates/sourcegen/src/lib.rs
+++ b/crates/sourcegen/src/lib.rs
@@ -1,4 +1,5 @@
 // Copyright contributors to the openqasm-parser project
+// SPDX-License-Identifier: Apache-2.0
 
 //! This was copied from an external crate. It would be better to use the
 //! external crate. But it has a bug-- a hard coded path that requires the
diff --git a/run_rustfmt.sh b/run_rustfmt.sh
index a68a57d..fedf107 100755
--- a/run_rustfmt.sh
+++ b/run_rustfmt.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # Ideally we want to run rustfmt on all crates
 cd crates/source_file && cargo fmt && cd ../..
diff --git a/run_tests.sh b/run_tests.sh
index 9be8ec0..d8fb249 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # Run the tests, but skip the tests that do codegen. They currently
 # are breaking the source. Or may break it.
diff --git a/run_tests_less.sh b/run_tests_less.sh
index 25edaf1..d9eef64 100755
--- a/run_tests_less.sh
+++ b/run_tests_less.sh
@@ -1,6 +1,7 @@
 #!/bin/env sh
 
 # Copyright contributors to the openqasm-parser project
+# SPDX-License-Identifier: Apache-2.0
 
 # Same as run_tests.sh, but pipe stderr to less