diff --git a/Cargo.lock b/Cargo.lock
index 36d06c8b9..b46aa6550 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1122,7 +1122,7 @@ dependencies = [
  "craft-offcrypto",
  "craft-opc",
  "craft-wordmodel",
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "log",
  "quick-xml 0.41.0",
  "thiserror 2.0.21",
@@ -1135,12 +1135,17 @@ name = "craft-drawingml"
 version = "0.1.0"
 source = "git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf#ba24fe2435adb3c81ad6057faf36365fbba736cf"
 dependencies = [
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "kurbo",
  "log",
  "serde",
 ]
 
+[[package]]
+name = "craft-eps"
+version = "0.1.0"
+source = "git+https://github.com/storytold/craft-libs?rev=6ba1ca33ca21c33de55ef155141db08ca6048e8d#6ba1ca33ca21c33de55ef155141db08ca6048e8d"
+
 [[package]]
 name = "craft-eps"
 version = "0.1.0"
@@ -1151,11 +1156,20 @@ name = "craft-epub"
 version = "0.1.0"
 source = "git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf#ba24fe2435adb3c81ad6057faf36365fbba736cf"
 dependencies = [
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "craft-zip",
  "thiserror 2.0.21",
 ]
 
+[[package]]
+name = "craft-file-formats"
+version = "0.1.0"
+source = "git+https://github.com/storytold/craft-libs?rev=6ba1ca33ca21c33de55ef155141db08ca6048e8d#6ba1ca33ca21c33de55ef155141db08ca6048e8d"
+dependencies = [
+ "craft-eps 0.1.0 (git+https://github.com/storytold/craft-libs?rev=6ba1ca33ca21c33de55ef155141db08ca6048e8d)",
+ "craft-svg 0.1.0 (git+https://github.com/storytold/craft-libs?rev=6ba1ca33ca21c33de55ef155141db08ca6048e8d)",
+]
+
 [[package]]
 name = "craft-fonts-build"
 version = "0.1.0"
@@ -1189,7 +1203,7 @@ name = "craft-idml"
 version = "0.1.0"
 source = "git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf#ba24fe2435adb3c81ad6057faf36365fbba736cf"
 dependencies = [
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "craft-zip",
  "thiserror 2.0.21",
 ]
@@ -1216,6 +1230,14 @@ dependencies = [
  "zune-jpegxl",
 ]
 
+[[package]]
+name = "craft-indd"
+version = "0.1.0"
+source = "git+https://github.com/storytold/craft-libs?rev=47bf5650b0d503b97bfb5e841746c4957897d11f#47bf5650b0d503b97bfb5e841746c4957897d11f"
+dependencies = [
+ "indd",
+]
+
 [[package]]
 name = "craft-jpeg"
 version = "0.1.0"
@@ -1241,7 +1263,7 @@ name = "craft-math"
 version = "0.1.0"
 source = "git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf#ba24fe2435adb3c81ad6057faf36365fbba736cf"
 dependencies = [
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "serde",
 ]
 
@@ -1253,7 +1275,7 @@ dependencies = [
  "aes",
  "base64 0.23.1",
  "craft-cfb",
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "getrandom 0.3.4",
  "hmac",
  "sha1 0.11.0",
@@ -1267,7 +1289,7 @@ name = "craft-opc"
 version = "0.1.0"
 source = "git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf#ba24fe2435adb3c81ad6057faf36365fbba736cf"
 dependencies = [
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "craft-zip",
  "log",
  "thiserror 2.0.21",
@@ -1337,12 +1359,24 @@ name = "craft-sheet"
 version = "0.1.0"
 source = "git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf#ba24fe2435adb3c81ad6057faf36365fbba736cf"
 
+[[package]]
+name = "craft-svg"
+version = "0.1.0"
+source = "git+https://github.com/storytold/craft-libs?rev=6ba1ca33ca21c33de55ef155141db08ca6048e8d#6ba1ca33ca21c33de55ef155141db08ca6048e8d"
+dependencies = [
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=6ba1ca33ca21c33de55ef155141db08ca6048e8d)",
+ "flate2",
+ "kurbo",
+ "roxmltree 0.21.2",
+ "thiserror 2.0.21",
+]
+
 [[package]]
 name = "craft-svg"
 version = "0.1.0"
 source = "git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf#ba24fe2435adb3c81ad6057faf36365fbba736cf"
 dependencies = [
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "flate2",
  "kurbo",
  "roxmltree 0.21.2",
@@ -1438,7 +1472,16 @@ dependencies = [
  "craft-drawingml",
  "craft-opc",
  "craft-sheet",
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
+ "thiserror 2.0.21",
+]
+
+[[package]]
+name = "craft-xml"
+version = "0.1.0"
+source = "git+https://github.com/storytold/craft-libs?rev=6ba1ca33ca21c33de55ef155141db08ca6048e8d#6ba1ca33ca21c33de55ef155141db08ca6048e8d"
+dependencies = [
+ "quick-xml 0.41.0",
  "thiserror 2.0.21",
 ]
 
@@ -1697,6 +1740,8 @@ dependencies = [
  "caseless",
  "craft-atomic",
  "craft-docpath",
+ "craft-file-formats",
+ "craft-indd",
  "craft-prepress",
  "craft-print",
  "designcraft-color",
@@ -1716,7 +1761,6 @@ dependencies = [
  "hayro-cmap",
  "hayro-interpret",
  "hayro-syntax",
- "indd",
  "kurbo",
  "log",
  "quick-xml 0.41.0",
@@ -1758,7 +1802,7 @@ name = "designcraft-format"
 version = "0.20.1"
 dependencies = [
  "craft-document-bundle",
- "craft-eps",
+ "craft-eps 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "designcraft-doc",
  "serde",
  "serde_json",
@@ -1784,7 +1828,7 @@ name = "designcraft-idml"
 version = "0.20.1"
 dependencies = [
  "craft-idml",
- "craft-xml",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "designcraft-color",
  "designcraft-compose",
  "designcraft-doc",
@@ -1800,10 +1844,11 @@ name = "designcraft-images"
 version = "0.20.1"
 dependencies = [
  "craft-cms",
- "craft-eps",
+ "craft-eps 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
+ "craft-file-formats",
  "craft-image-codecs",
  "craft-psd",
- "craft-svg",
+ "craft-svg 0.1.0 (git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad6057faf36365fbba736cf)",
  "designcraft-color",
  "designcraft-fonts",
  "flate2",
@@ -1896,6 +1941,7 @@ name = "designcraft-textimport"
 version = "0.20.1"
 dependencies = [
  "craft-docx",
+ "craft-file-formats",
  "craft-idml",
  "craft-rtf",
  "craft-wordmodel",
diff --git a/Cargo.toml b/Cargo.toml
index 54833bb50..2b2f09020 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,6 +17,7 @@ craft-document-bundle = { git = "https://github.com/storytold/craft-libs", rev =
 craft-eps = { git = "https://github.com/storytold/craft-libs", rev = "ba24fe2435adb3c81ad6057faf36365fbba736cf", version = "=0.1.0" }
 craft-epub = { git = "https://github.com/storytold/craft-libs", rev = "ba24fe2435adb3c81ad6057faf36365fbba736cf", version = "=0.1.0" }
 craft-idml = { git = "https://github.com/storytold/craft-libs", rev = "ba24fe2435adb3c81ad6057faf36365fbba736cf", version = "=0.1.0" }
+craft-indd = { git = "https://github.com/storytold/craft-libs", rev = "47bf5650b0d503b97bfb5e841746c4957897d11f", version = "=0.1.0" }
 craft-svg = { git = "https://github.com/storytold/craft-libs", rev = "ba24fe2435adb3c81ad6057faf36365fbba736cf", version = "=0.1.0" }
 craft-xml = { git = "https://github.com/storytold/craft-libs", rev = "ba24fe2435adb3c81ad6057faf36365fbba736cf", version = "=0.1.0" }
 craft-rtf = { git = "https://github.com/storytold/craft-libs", rev = "ba24fe2435adb3c81ad6057faf36365fbba736cf", version = "=0.1.0" }
@@ -25,6 +26,7 @@ craft-docx = { git = "https://github.com/storytold/craft-libs", rev = "ba24fe243
 craft-wordmodel = { git = "https://github.com/storytold/craft-libs", rev = "ba24fe2435adb3c81ad6057faf36365fbba736cf", version = "=0.1.0" }
 craft-image-codecs = { git = "https://github.com/storytold/craft-libs", rev = "a47b78256c6acf3d7fdc4bc7cfbc25c373eac522", version = "=0.1.0" }
 craft-psd = { git = "https://github.com/storytold/craft-libs", rev = "a47b78256c6acf3d7fdc4bc7cfbc25c373eac522", version = "=0.1.0" }
+craft-file-formats = { git = "https://github.com/storytold/craft-libs", rev = "6ba1ca33ca21c33de55ef155141db08ca6048e8d", version = "=0.1.0" }
 # Shared keyboard bindings: chords, overrides, conflicts, egui dispatch, the Keyboard Shortcuts dialog.
 craft-keymap = { git = "https://github.com/storytold/craft-libs", rev = "92d392cff132eaf53e13afff77f38b5c11b73aa0", version = "=0.1.0", features = ["egui", "ui"] }
 # Separations, ink coverage and the ink manager; same revision as craft-pdf and the krilla patch.
@@ -88,13 +90,6 @@ flo_curves = "0.8"
 qrcodegen = "1.8"
 quick-xml = "0.41"
 zip = { version = "3", default-features = false, features = ["deflate"] }
-# INDD/INDT → IDML conversion for File › Open: storytold/indd-utils, pinned by rev as every other
-# git dependency here is. It parses untrusted INDD files, and `branch = "main"` meant any
-# `cargo update` -- Dependabot runs them -- pulled whatever was on that branch into the parser
-# without review (#1599).
-# (MIT OR Apache-2.0, no dependencies, builds for wasm).
-indd = { git = "https://github.com/storytold/indd-utils", rev = "7f3060e5bce78d21ea70e0d5eacb96edce15dfbe" }
-
 # Which paths stored in documents may be followed (craft-libs).
 craft-docpath = { version = "0.1.0", git = "https://github.com/storytold/craft-libs", rev = "92d392cff132eaf53e13afff77f38b5c11b73aa0" }
 # Atomic file replacement for saves and exports (craft-libs).
diff --git a/crates/engine/Cargo.toml b/crates/engine/Cargo.toml
index c1c0f1d33..ed9e7e3bc 100644
--- a/crates/engine/Cargo.toml
+++ b/crates/engine/Cargo.toml
@@ -26,7 +26,8 @@ designcraft-pdf = { workspace = true }
 craft-prepress = { workspace = true }
 designcraft-tools = { workspace = true }
 designcraft-idml = { workspace = true }
-indd = { workspace = true }
+craft-file-formats = { workspace = true }
+craft-indd = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 thiserror = { workspace = true }
diff --git a/crates/engine/src/cmd/book.rs b/crates/engine/src/cmd/book.rs
index a4217f825..b1de3dac7 100644
--- a/crates/engine/src/cmd/book.rs
+++ b/crates/engine/src/cmd/book.rs
@@ -57,7 +57,7 @@ fn load(path: &str) -> Result<designcraft_doc::Document> {
         let _ = path;
         vec![]
     };
-    if path.to_lowercase().ends_with(".idml") {
+    if craft_file_formats::detect(path, &bytes) == Some(craft_file_formats::Format::Idml) {
         return super::interchange::import_idml_confined(&bytes, Some(std::path::Path::new(path)))
             .map_err(|e| EngineError::Other(format!("{path}: {e}")));
     }
diff --git a/crates/engine/src/cmd/file/open.rs b/crates/engine/src/cmd/file/open.rs
index 529ec2d96..e88d75afc 100644
--- a/crates/engine/src/cmd/file/open.rs
+++ b/crates/engine/src/cmd/file/open.rs
@@ -84,12 +84,17 @@ fn open_path(s: &mut Session, p: &Value) -> Result<Value> {
         let bytes = crate::io::read_file(path).map_err(EngineError::Other)?;
         // The content decides first: a file's extension may be missing or wrong. The extension
         // then routes files whose content isn't recognised to the reader that explains why.
-        let ext = std::path::Path::new(path).extension().and_then(std::ffi::OsStr::to_str).unwrap_or_default().to_ascii_lowercase();
-        let native = designcraft_format::is_designcraft(&bytes) || bytes.trim_ascii_start().starts_with(b"{");
-        if designcraft_idml::is_idml(&bytes) || (!native && (crate::cmd::interchange::is_indd(path, &bytes) || ext == "idml")) {
+        let format = craft_file_formats::detect(path, &bytes);
+        let native = format == Some(craft_file_formats::Format::DesignCraft)
+            || designcraft_format::is_designcraft(&bytes)
+            || bytes.trim_ascii_start().starts_with(b"{");
+        if format == Some(craft_file_formats::Format::Idml)
+            || designcraft_idml::is_idml(&bytes)
+            || (!native && format == Some(craft_file_formats::Format::Indd))
+        {
             return crate::cmd::interchange::open_idml(s, p);
         }
-        if !native && ext != designcraft_format::EXTENSION {
+        if !native {
             return Err(bad("file.open", format!("{path}: not a DesignCraft or IDML file")));
         }
         let (mut d, mut warnings) = load_bytes(&bytes)?;
@@ -156,7 +161,13 @@ pub(super) fn file_open_bytes(s: &mut Session, p: &Value) -> Result<Value> {
     let b = base64_decode(str_param(p, "base64").unwrap_or(""));
     // IDML packages are recognised by their stored `mimetype` first entry, INDD files by their
     // signature (or their name).
-    if designcraft_idml::is_idml(&b) || crate::cmd::interchange::is_indd(str_param(p, "name").unwrap_or_default(), &b) {
+    let name = str_param(p, "name").unwrap_or_default();
+    let format = craft_file_formats::detect(name, &b);
+    let native = designcraft_format::is_designcraft(&b) || b.trim_ascii_start().starts_with(b"{");
+    if format == Some(craft_file_formats::Format::Idml)
+        || designcraft_idml::is_idml(&b)
+        || (!native && format == Some(craft_file_formats::Format::Indd))
+    {
         return crate::cmd::interchange::open_idml(s, p);
     }
     let (mut d, warnings) = load_bytes(&b)?;
diff --git a/crates/engine/src/cmd/file/place.rs b/crates/engine/src/cmd/file/place.rs
index a30cb2321..6d5236734 100644
--- a/crates/engine/src/cmd/file/place.rs
+++ b/crates/engine/src/cmd/file/place.rs
@@ -32,9 +32,9 @@ pub(super) fn file_place(s: &mut Session, p: &Value) -> Result<Value> {
         return Err(bad("file.place", "the frame is locked"));
     }
     // A page of another layout (IDML or DesignCraft): its objects, as one group.
-    let lname = name.to_lowercase();
-    if lname.ends_with(".idml") || lname.ends_with(".designcraft") {
-        return place_layout_page(s, p, &name, &bytes);
+    let format = craft_file_formats::detect(&name, &bytes);
+    if matches!(format, Some(craft_file_formats::Format::Idml | craft_file_formats::Format::DesignCraft)) {
+        return place_layout_page(s, p, &bytes, format);
     }
     // Keep the EPS source for link comparison; rendering uses its preview at the bounding box size.
     let eps_size = eps_size(&bytes, "file.place")?;
@@ -57,11 +57,11 @@ pub(super) fn file_place(s: &mut Session, p: &Value) -> Result<Value> {
         })
         .transpose()?;
     // Image Import Options: which page of a PDF (1-based).
-    if designcraft_render::is_pdf(&bytes) {
+    if format == Some(craft_file_formats::Format::Pdf) {
         designcraft_render::check_pdf_input_size(bytes.len()).map_err(|e| bad("file.place", e.to_string()))?;
     }
     let pdf_page = match p.get("pdfPage").and_then(Value::as_u64) {
-        Some(n) if designcraft_render::is_pdf(&bytes) => {
+        Some(n) if format == Some(craft_file_formats::Format::Pdf) => {
             let count = designcraft_render::pdf_page_count(&bytes).unwrap_or(1);
             let invalid_page = || bad("file.place", format!("the PDF has {count} page(s)"));
             let one_based = usize::try_from(n).map_err(|_| invalid_page())?;
@@ -83,7 +83,7 @@ pub(super) fn file_place(s: &mut Session, p: &Value) -> Result<Value> {
     // and SVGs keep their exact size: rounding it to whole points would stretch them unevenly.
     let (nw, nh) = eps_size.or_else(|| designcraft_render::natural_size(&bytes, pdf_page as usize)).unwrap_or((pw as f64, ph as f64));
     // Image Import Options › Crop to: the graphic spans that box of the PDF page.
-    let is_pdf = designcraft_render::is_pdf(&bytes);
+    let is_pdf = format == Some(craft_file_formats::Format::Pdf);
     let pdf_crop = match str_param(p, "pdfCrop") {
         Some(k) if is_pdf => PdfCrop::from_name(k)
             .ok_or_else(|| bad("file.place", format!("unknown pdfCrop `{k}` (crop, art, trim, bleed, media, contentVisible, contentAll)")))?,
@@ -347,9 +347,9 @@ pub(super) fn place_drop(s: &mut Session, p: &Value) -> Result<Value> {
 
 /// File › Place of an IDML or DesignCraft document: the objects of one page (`layoutPage`,
 /// 1-based) grouped, top-left at x/y (default: the source position on the first page).
-fn place_layout_page(s: &mut Session, p: &Value, name: &str, bytes: &[u8]) -> Result<Value> {
+fn place_layout_page(s: &mut Session, p: &Value, bytes: &[u8], format: Option<craft_file_formats::Format>) -> Result<Value> {
     const ID: &str = "file.place";
-    let src = if name.to_lowercase().ends_with(".idml") {
+    let src = if format == Some(craft_file_formats::Format::Idml) {
         crate::cmd::interchange::import_idml_confined(bytes, str_param(p, "path").map(std::path::Path::new)).map_err(|e| bad(ID, e.to_string()))?
     } else {
         from_bytes(bytes)?
diff --git a/crates/engine/src/cmd/file/save.rs b/crates/engine/src/cmd/file/save.rs
index d94a02ab9..d12bf03fa 100644
--- a/crates/engine/src/cmd/file/save.rs
+++ b/crates/engine/src/cmd/file/save.rs
@@ -89,11 +89,11 @@ pub(super) fn file_revert(s: &mut Session, _: &Value) -> Result<Value> {
     let path = s.doc()?.path.clone().ok_or_else(|| bad("file.revert", "the document has never been saved"))?;
     #[cfg(not(target_arch = "wasm32"))]
     {
-        let mut d = if path.to_ascii_lowercase().ends_with(".idml") {
-            let bytes = crate::io::read_file(&path).map_err(EngineError::Other)?;
+        let bytes = crate::io::read_file(&path).map_err(EngineError::Other)?;
+        let mut d = if craft_file_formats::detect(&path, &bytes) == Some(craft_file_formats::Format::Idml) {
             crate::cmd::interchange::import_idml_confined(&bytes, Some(std::path::Path::new(&path))).map_err(|e| EngineError::Other(e.to_string()))?
         } else {
-            from_bytes(&crate::io::read_file(&path).map_err(EngineError::Other)?)?
+            from_bytes(&bytes)?
         };
         // As opened again: the fonts beside it now (unchanged files are shared, not read again).
         let (fonts, _, _) = load_document_fonts(&mut d, &path);
diff --git a/crates/engine/src/cmd/interchange.rs b/crates/engine/src/cmd/interchange.rs
index 47b36b776..0fba3b900 100644
--- a/crates/engine/src/cmd/interchange.rs
+++ b/crates/engine/src/cmd/interchange.rs
@@ -418,7 +418,7 @@ pub(crate) fn open_idml(s: &mut Session, p: &Value) -> Result<Value> {
     let mut previews = std::collections::HashMap::new();
     let bytes = if is_indd(&file, &bytes) {
         // What the converter can't read still comes over as IDML (#21).
-        let conversion = indd::convert(&bytes, &file).map_err(|e| {
+        let conversion = craft_indd::convert(&bytes, &file).map_err(|e| {
             EngineError::Other(format!(
                 "can't convert the InDesign file: {e}. In InDesign, choose File ▸ Export… ▸ InDesign Markup (IDML) and open the .idml in DesignCraft."
             ))
@@ -470,19 +470,19 @@ fn warning_item(
 /// the bytes are neither a recognized DesignCraft document nor IDML. The converter explains
 /// unrecognized data with an InDesign extension.
 pub(crate) fn is_indd(name: &str, bytes: &[u8]) -> bool {
-    bytes.starts_with(&indd::header::SIGNATURE)
-        || (has_indd_extension(name) && !super::file::is_document(bytes) && !bytes.trim_ascii_start().starts_with(b"{"))
-}
-
-pub(crate) fn has_indd_extension(name: &str) -> bool {
-    let n = name.to_ascii_lowercase();
-    n.ends_with(".indd") || n.ends_with(".indt")
+    craft_file_formats::detect(name, bytes) == Some(craft_file_formats::Format::Indd)
+        && !super::file::is_document(bytes)
+        && !bytes.trim_ascii_start().starts_with(b"{")
 }
 
 /// `name` without a trailing .idml, .indd or .indt (any case).
 fn without_document_extension(name: &str) -> &str {
     match name.rsplit_once('.') {
-        Some((stem, ext)) if ["idml", "indd", "indt"].iter().any(|e| ext.eq_ignore_ascii_case(e)) => stem,
+        Some((stem, ext))
+            if matches!(craft_file_formats::from_extension(ext), Some(craft_file_formats::Format::Idml | craft_file_formats::Format::Indd)) =>
+        {
+            stem
+        }
         _ => name,
     }
 }
@@ -683,7 +683,7 @@ mod tests {
     /// name) go to the converter, and what it can't read is an open error that adds no document.
     #[test]
     fn indd_files_go_through_the_converter_and_its_errors_are_open_errors() {
-        let mut signed = indd::header::SIGNATURE.to_vec();
+        let mut signed = craft_indd::SIGNATURE.to_vec();
         signed.resize(4096, 0);
         let cases = [(signed, "Brochure"), (vec![0; 4096], "Brochure.indd"), (b"not an InDesign file".to_vec(), "Template.INDT")];
         let mut s = Session::new();
diff --git a/crates/engine/src/cmd/load_styles.rs b/crates/engine/src/cmd/load_styles.rs
index 762f7b1fc..154306048 100644
--- a/crates/engine/src/cmd/load_styles.rs
+++ b/crates/engine/src/cmd/load_styles.rs
@@ -85,7 +85,7 @@ fn source(p: &Value, id: &str) -> Result<Document> {
         (Some(path), None) => (crate::io::read_file(path).map_err(|e| bad(id, e))?, path.to_string()),
         _ => return Err(bad(id, "give `path` or `base64`")),
     };
-    if name.to_lowercase().ends_with(".idml") {
+    if craft_file_formats::detect(&name, &bytes) == Some(craft_file_formats::Format::Idml) {
         designcraft_idml::import_idml(&bytes).map_err(|e| bad(id, e.to_string()))
     } else {
         super::file::from_bytes(&bytes).map_err(|e| bad(id, e.to_string()))
diff --git a/crates/images/Cargo.toml b/crates/images/Cargo.toml
index 6b58daccb..f2cd6b362 100644
--- a/crates/images/Cargo.toml
+++ b/crates/images/Cargo.toml
@@ -20,6 +20,7 @@ log = { workspace = true }
 craft-cms = { workspace = true }
 craft-image-codecs = { workspace = true }
 craft-psd = { workspace = true }
+craft-file-formats = { workspace = true }
 
 [dev-dependencies]
 designcraft-fonts = { workspace = true, features = ["testing"] }
diff --git a/crates/images/src/jpeg.rs b/crates/images/src/jpeg.rs
deleted file mode 100644
index 8b44d0c9a..000000000
--- a/crates/images/src/jpeg.rs
+++ /dev/null
@@ -1,80 +0,0 @@
-//! CMYK and YCCK JPEGs, decoded to their ink values (the `image` crate converts them to RGB with
-//! a profile-free formula).
-
-use zune_core::bytestream::ZCursor;
-use zune_core::colorspace::ColorSpace;
-use zune_core::options::DecoderOptions;
-use zune_jpeg::JpegDecoder;
-
-use crate::CmykRaster;
-
-/// The largest decoded image, in bytes (the `image` crate's default allocation limit).
-const MAX_BYTES: usize = 512 << 20;
-
-fn decoder(bytes: &[u8], out: ColorSpace) -> JpegDecoder<ZCursor<&[u8]>> {
-    let options = DecoderOptions::default().set_strict_mode(false).set_max_width(65_535).set_max_height(65_535).jpeg_set_out_colorspace(out);
-    JpegDecoder::new_with_options(ZCursor::new(bytes), options)
-}
-
-/// A four-channel JPEG's inks (0 = no ink) and its embedded ICC profile. `None` for other JPEGs
-/// and for anything that doesn't decode.
-pub(crate) fn decode_cmyk(bytes: &[u8]) -> Option<(CmykRaster, Option<Vec<u8>>)> {
-    if !bytes.starts_with(&[0xFF, 0xD8]) {
-        return None;
-    }
-    let mut d = decoder(bytes, ColorSpace::RGB);
-    d.decode_headers().ok()?;
-    let space = d.input_colorspace()?;
-    if !matches!(space, ColorSpace::CMYK | ColorSpace::YCCK) {
-        return None;
-    }
-    let info = d.info()?;
-    let (w, h) = (usize::from(info.width), usize::from(info.height));
-    let pixels = w.checked_mul(h)?;
-    if pixels.checked_mul(4)? > MAX_BYTES {
-        return None;
-    }
-    // Decoding into the input colour space copies the channels as stored.
-    let mut d = decoder(bytes, space);
-    let mut px = d.decode().ok()?;
-    if px.len() != pixels.checked_mul(4)? {
-        return None;
-    }
-    let icc = d.icc_profile();
-    if space == ColorSpace::YCCK {
-        // YCbCr encodes 255 − the first three stored values (JFIF conversion); K is as stored.
-        for p in px.as_chunks_mut::<4>().0 {
-            let (y, cb, cr) = (f32::from(p[0]), f32::from(p[1]) - 128.0, f32::from(p[2]) - 128.0);
-            let byte = |v: f32| 255 - v.round().clamp(0.0, 255.0) as u8;
-            p[0] = byte(y + 1.402 * cr);
-            p[1] = byte(y - 0.344_136 * cb - 0.714_136 * cr);
-            p[2] = byte(y + 1.772 * cb);
-        }
-    }
-    // Adobe's APP14 marker (always there for YCCK) means the values are stored inverted:
-    // 255 = no ink.
-    if space == ColorSpace::YCCK || adobe_marker(bytes) {
-        for v in &mut px {
-            *v = 255 - *v;
-        }
-    }
-    let raster = CmykRaster { width: u32::try_from(w).ok()?, height: u32::try_from(h).ok()?, cmyk: px, alpha: None };
-    Some((raster, icc))
-}
-
-/// Whether an APP14 "Adobe" segment comes before the image data.
-fn adobe_marker(bytes: &[u8]) -> bool {
-    let mut i = 2;
-    while let Some(&[0xFF, marker, hi, lo]) = bytes.get(i..i + 4).and_then(|s| <&[u8; 4]>::try_from(s).ok()) {
-        // Start of scan or end of image: no more header segments.
-        if marker == 0xDA || marker == 0xD9 {
-            return false;
-        }
-        let len = usize::from(u16::from_be_bytes([hi, lo]));
-        if marker == 0xEE && bytes.get(i + 4..i + 9) == Some(b"Adobe".as_slice()) {
-            return true;
-        }
-        i += 2 + len;
-    }
-    false
-}
diff --git a/crates/images/src/lib.rs b/crates/images/src/lib.rs
index b9209e65e..a4c9d9b86 100644
--- a/crates/images/src/lib.rs
+++ b/crates/images/src/lib.rs
@@ -20,39 +20,37 @@ pub use tone::{Tone, tone};
 pub const PT_PER_PX: f64 = 0.75;
 
 pub fn is_pdf(bytes: &[u8]) -> bool {
-    bytes.starts_with(b"%PDF")
+    file_format(bytes) == Some(craft_file_formats::Format::Pdf)
 }
 
 pub fn is_psd(bytes: &[u8]) -> bool {
-    craft_psd::head::sniff(bytes)
+    file_format(bytes) == Some(craft_file_formats::Format::Psd)
 }
 
 /// An SVG document (optionally after an XML declaration, comments or a doctype).
 pub fn is_svg(bytes: &[u8]) -> bool {
-    craft_svg::sniff::is_svg(bytes)
+    file_format(bytes) == Some(craft_file_formats::Format::Svg)
+}
+
+pub fn file_format(bytes: &[u8]) -> Option<craft_file_formats::Format> {
+    craft_file_formats::detect("", bytes)
 }
 
 /// MIME type of a placed graphic.
 pub fn mime(bytes: &[u8]) -> &'static str {
-    if is_eps(bytes) {
-        return "application/postscript";
-    }
-    if is_pdf(bytes) {
-        return "application/pdf";
-    }
-    if is_psd(bytes) {
-        return "image/vnd.adobe.photoshop";
-    }
-    if is_svg(bytes) {
-        return "image/svg+xml";
-    }
-    match craft_image_codecs::detect(bytes) {
-        Some(craft_image_codecs::Format::Png) => "image/png",
-        Some(craft_image_codecs::Format::Jpeg) => "image/jpeg",
-        Some(craft_image_codecs::Format::Gif) => "image/gif",
-        Some(craft_image_codecs::Format::WebP) => "image/webp",
-        Some(craft_image_codecs::Format::Tiff) => "image/tiff",
-        Some(craft_image_codecs::Format::Bmp) => "image/bmp",
+    match file_format(bytes) {
+        Some(craft_file_formats::Format::Eps | craft_file_formats::Format::PostScript | craft_file_formats::Format::Illustrator) => {
+            "application/postscript"
+        }
+        Some(craft_file_formats::Format::Pdf) => "application/pdf",
+        Some(craft_file_formats::Format::Psd) => "image/vnd.adobe.photoshop",
+        Some(craft_file_formats::Format::Svg) => "image/svg+xml",
+        Some(craft_file_formats::Format::Png) => "image/png",
+        Some(craft_file_formats::Format::Jpeg) => "image/jpeg",
+        Some(craft_file_formats::Format::Gif) => "image/gif",
+        Some(craft_file_formats::Format::WebP) => "image/webp",
+        Some(craft_file_formats::Format::Tiff) => "image/tiff",
+        Some(craft_file_formats::Format::Bmp) => "image/bmp",
         _ => "application/octet-stream",
     }
 }
diff --git a/crates/pdf/src/export/images.rs b/crates/pdf/src/export/images.rs
index f4d4a0a98..4ddafa82d 100644
--- a/crates/pdf/src/export/images.rs
+++ b/crates/pdf/src/export/images.rs
@@ -180,7 +180,7 @@ pub(super) fn recompress(data: &[u8], mode: RasterMode) -> Option<Image> {
     }
     let img = craft_image_codecs::decode(data).ok()?;
     let rgba = img.to_rgba8();
-    if img.layout().has_alpha() && rgba.chunks_exact(4).any(|p| p[3] < 255) {
+    if img.layout().has_alpha() && rgba.as_chunks::<4>().0.iter().any(|p| p[3] < 255) {
         return None;
     }
     // A grey image stays a grey JPEG (#1426).
diff --git a/crates/textimport/Cargo.toml b/crates/textimport/Cargo.toml
index 460458ddf..968a488c4 100644
--- a/crates/textimport/Cargo.toml
+++ b/crates/textimport/Cargo.toml
@@ -15,6 +15,7 @@ craft-xlsx = { workspace = true }
 craft-docx = { workspace = true }
 craft-wordmodel = { workspace = true }
 craft-idml = { workspace = true }
+craft-file-formats = { workspace = true }
 
 [dev-dependencies]
 zip = { workspace = true }
diff --git a/crates/textimport/src/lib.rs b/crates/textimport/src/lib.rs
index 0838861e2..78a619bbc 100644
--- a/crates/textimport/src/lib.rs
+++ b/crates/textimport/src/lib.rs
@@ -64,27 +64,28 @@ impl std::fmt::Display for ImportError {
 
 /// Text files this crate reads, by extension.
 pub fn is_text_file(name: &str) -> bool {
-    let l = name.to_ascii_lowercase();
-    l.ends_with(".txt") || l.ends_with(".text") || l.ends_with(".md") || l.ends_with(".docx") || l.ends_with(".rtf") || l.ends_with(".xlsx")
+    matches!(
+        craft_file_formats::detect(name, &[]),
+        Some(
+            craft_file_formats::Format::PlainText
+                | craft_file_formats::Format::Docx
+                | craft_file_formats::Format::Rtf
+                | craft_file_formats::Format::Xlsx
+        )
+    )
 }
 
 /// Import `bytes` (format from the file name, else sniffed).
 pub fn import(name: &str, bytes: &[u8]) -> Result<Imported, ImportError> {
-    let l = name.to_ascii_lowercase();
-    if l.ends_with(".xlsx") {
-        return xlsx::import(bytes);
-    }
-    if l.ends_with(".docx") || bytes.starts_with(b"PK\x03\x04") {
-        return docx::import(bytes);
-    }
-    if l.ends_with(".rtf") || bytes.starts_with(b"{\\rtf") {
-        return rtf::import(bytes);
-    }
-    if tagged::is_tagged(bytes) {
-        return tagged::import(bytes);
-    }
-    if l.ends_with(".doc") {
-        return Err(ImportError::Unsupported("legacy Word .doc (save it as .docx)".into()));
+    match craft_file_formats::detect(name, bytes) {
+        Some(craft_file_formats::Format::Xlsx) => return xlsx::import(bytes),
+        Some(craft_file_formats::Format::Docx) => return docx::import(bytes),
+        Some(craft_file_formats::Format::Rtf) => return rtf::import(bytes),
+        Some(craft_file_formats::Format::TaggedText) => return tagged::import(bytes),
+        Some(craft_file_formats::Format::LegacyDoc) => {
+            return Err(ImportError::Unsupported("legacy Word .doc (save it as .docx)".into()));
+        }
+        _ => {}
     }
     Ok(plain(&tagged::decode(bytes)))
 }