diff --git a/Cargo.lock b/Cargo.lock
index 58cabfc5..141a9053 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -208,6 +208,15 @@ version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b4682ae6287fcf752ecaabbfcc7b6f9b72aa33933dc23a554d853aea8eea8635"
 
+[[package]]
+name = "blake2"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46502ad458c9a52b69d4d4d32775c788b7a1b85e8bc9d482d92250fc0e3f8efe"
+dependencies = [
+ "digest",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.10.2"
@@ -456,6 +465,7 @@ checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
 dependencies = [
  "block-buffer",
  "crypto-common",
+ "subtle",
 ]
 
 [[package]]
@@ -643,6 +653,21 @@ dependencies = [
  "wasm-bindgen-test",
 ]
 
+[[package]]
+name = "expander"
+version = "2.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2c470c71d91ecbd179935b24170459e926382eaaa86b590b78814e180d8a8e2"
+dependencies = [
+ "blake2",
+ "file-guard",
+ "fs-err",
+ "prettyplease",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.66",
+]
+
 [[package]]
 name = "expectorate"
 version = "1.1.0"
@@ -660,6 +685,16 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "25cbce373ec4653f1a01a31e8a5e5ec0c622dc27ff9c4e6606eefef5cbbed4a5"
 
+[[package]]
+name = "file-guard"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "21ef72acf95ec3d7dbf61275be556299490a245f017cf084bd23b4f68cf9407c"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -690,6 +725,15 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "fs-err"
+version = "2.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88a41f105fe1d5b6b34b2055e3dc59bb79b46b48b2040b9e6c7b4b5de097aa41"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "futures"
 version = "0.3.30"
@@ -1390,6 +1434,7 @@ version = "0.7.0"
 dependencies = [
  "base64 0.22.1",
  "chrono",
+ "expander",
  "futures",
  "percent-encoding",
  "progenitor-client",
@@ -1451,6 +1496,7 @@ dependencies = [
 name = "progenitor-macro"
 version = "0.7.0"
 dependencies = [
+ "expander",
  "openapiv3",
  "proc-macro2",
  "progenitor-impl",
diff --git a/progenitor-macro/Cargo.toml b/progenitor-macro/Cargo.toml
index c7af7197..ff447442 100644
--- a/progenitor-macro/Cargo.toml
+++ b/progenitor-macro/Cargo.toml
@@ -21,3 +21,4 @@ serde_json = "1.0"
 serde_yaml = "0.9"
 serde_tokenstream = "0.2.0"
 syn = { version = "2.0", features = ["full", "extra-traits"] }
+expander = "2.2.1"
diff --git a/progenitor-macro/src/lib.rs b/progenitor-macro/src/lib.rs
index 60111f3b..419ffe42 100644
--- a/progenitor-macro/src/lib.rs
+++ b/progenitor-macro/src/lib.rs
@@ -9,6 +9,7 @@ use std::{
     fmt::Display,
     fs::File,
     path::{Path, PathBuf},
+    str::FromStr,
 };
 
 use openapiv3::OpenAPI;
@@ -405,5 +406,17 @@ fn do_generate_api(item: TokenStream) -> Result<TokenStream, syn::Error> {
         const _: &str = include_str!(#path_str);
     };
 
+    let output = if let Some(dest) = std::env::var("PROGENITOR_OUTPUT_DEBUG")
+        .map(|ref s| {std::path::PathBuf::from_str(s).expect("Environment var `PROGENITOR_OUTPUT_DEBUG` must contain a valid path")}).ok()
+    {
+        eprintln!("Writing generated output to {}", path.display());
+        expander::Expander::new(dest.file_name().expect("Environment var `PROGENITOR_OUTPUT_DEBUG` must contain path with filename").to_string_lossy())
+        .fmt(expander::Edition::_2021)
+        .verbose(true)
+        .write_to(output, dest.parent().expect("If path has filename, parent must be root / drive at least. qed"))
+        .expect("Writing file works. qed")
+    } else {
+        output
+    };
     Ok(output.into())
 }
diff --git a/progenitor/Cargo.toml b/progenitor/Cargo.toml
index 68537f83..96606ffc 100644
--- a/progenitor/Cargo.toml
+++ b/progenitor/Cargo.toml
@@ -13,6 +13,7 @@ categories = ["api-bindings", "compilers"]
 progenitor-client = { workspace = true }
 progenitor-impl = { workspace = true }
 progenitor-macro = { workspace = true }
+expander = "2.1.0"
 
 [dev-dependencies]
 base64 = { workspace = true }