diff --git a/ROADMAP.md b/ROADMAP.md
index f09076dc..eab8720b 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -58,7 +58,7 @@ _Last updated: 2026-10-01._
 | M2 | Drawing tools + smart guides | ✅ mostly done (Shaper, Pen modifier nuances) | 5–10 |
 | M3 | Paint & appearance (swatches, color, gradient, stroke, appearance, transparency, styles) | 🟡 panels done; opacity masks done (make/release, clip, invert, disable, link; render + SVG `<mask>` in/out + PDF soft mask); mask-editing mode, freeform gradients pending | 6–10 |
 | M4 | Files (native, SVG, PDF, raster, Export for Screens, clipboard interop) | 🟡 Export for Screens (PNG/JPG/WebP/SVG/PDF × scales) done; headless CLI/MCP export every format; system clipboard: copy puts SVG markup on it, paste takes SVG from other apps (Ctrl/Cmd+C/X/V now also work off macOS); PNG/PDF clipboard flavours, EPS/DXF pending | 8–12 |
-| M5 | Performance | 🟡 background render + caches + MT done; `drawcraft-cli bench`; raster effects (glows, shadows, blur, feather) no longer force the whole frame single-threaded (filtered offscreen per effect, verified equal to the single-threaded reference); effect-heavy demos need a clean-machine benchmark; dirty-region rendering, GPU backend spike pending | 10–20 |
+| M5 | Performance | 🟡 background render + caches + MT done; `drawcraft-cli bench` and `drawcraft-cli perf` (budget suite); file format v2 opens 3× faster (50k paths: 722 → 244 ms); raster effects (glows, shadows, blur, feather) no longer force the whole frame single-threaded (filtered offscreen per effect, verified equal to the single-threaded reference); effect-heavy demos need a clean-machine benchmark; dirty-region rendering, GPU backend spike pending | 10–20 |
 | M6 | Path operations (Pathfinder, Shape Builder, offset…) | ✅ mostly done (Shape Builder edge erase, large-offset bug open) | 3–6 |
 | M7 | Type (point/area/path, editing, styles, OpenType, threading, glyphs) | 🟡 in progress | 20–30 |
 | M8 | Transform & distort (Puppet Warp, Liquify tools, Envelopes, Blends, Perspective Grid) | 🟡 live Blends, Envelopes (warp/mesh/top object), Width tool, Liquify tools, Puppet Warp and Perspective Grid landed; fidelity pass pending | 8–12 |
diff --git a/crates/doc/src/appearance.rs b/crates/doc/src/appearance.rs
index eb7c25a2..a25079b0 100644
--- a/crates/doc/src/appearance.rs
+++ b/crates/doc/src/appearance.rs
@@ -126,11 +126,11 @@ fn one() -> f32 {
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct FillLayer {
     pub paint: Paint,
-    #[serde(default = "one")]
+    #[serde(default = "one", skip_serializing_if = "crate::skip::is_one")]
     pub opacity: f32,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub blend: BlendMode,
-    #[serde(default = "yes")]
+    #[serde(default = "yes", skip_serializing_if = "crate::skip::is_true")]
     pub visible: bool,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub effects: Vec<Effect>,
@@ -147,13 +147,13 @@ pub struct StrokeLayer {
     pub paint: Paint,
     /// Weight in points.
     pub width: f64,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub cap: LineCap,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub join: LineJoin,
-    #[serde(default = "ten")]
+    #[serde(default = "ten", skip_serializing_if = "is_ten")]
     pub miter_limit: f64,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub align: StrokeAlign,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub dash: Option<Dash>,
@@ -162,18 +162,18 @@ pub struct StrokeLayer {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub end_arrow: Option<Arrowhead>,
     /// Arrowhead scale in percent (start, end).
-    #[serde(default = "hundreds")]
+    #[serde(default = "hundreds", skip_serializing_if = "is_hundreds")]
     pub arrow_scale: (f64, f64),
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub profile: Option<WidthProfile>,
     /// Brush applied to the stroke (by brush name).
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub brush: Option<String>,
-    #[serde(default = "one")]
+    #[serde(default = "one", skip_serializing_if = "crate::skip::is_one")]
     pub opacity: f32,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub blend: BlendMode,
-    #[serde(default = "yes")]
+    #[serde(default = "yes", skip_serializing_if = "crate::skip::is_true")]
     pub visible: bool,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub effects: Vec<Effect>,
@@ -185,6 +185,12 @@ fn ten() -> f64 {
 fn hundreds() -> (f64, f64) {
     (100.0, 100.0)
 }
+fn is_ten(v: &f64) -> bool {
+    *v == 10.0
+}
+fn is_hundreds(v: &(f64, f64)) -> bool {
+    *v == (100.0, 100.0)
+}
 
 impl StrokeLayer {
     pub fn new(paint: Paint, width: f64) -> Self {
diff --git a/crates/doc/src/lib.rs b/crates/doc/src/lib.rs
index c3819c14..3d39aab9 100644
--- a/crates/doc/src/lib.rs
+++ b/crates/doc/src/lib.rs
@@ -16,6 +16,19 @@ pub mod text;
 use std::collections::BTreeMap;
 use std::sync::Arc;
 
+/// `skip_serializing_if` predicates: fields equal to their serde default are not written.
+pub(crate) mod skip {
+    pub fn is_default<T: Default + PartialEq>(v: &T) -> bool {
+        *v == T::default()
+    }
+    pub fn is_true(v: &bool) -> bool {
+        *v
+    }
+    pub fn is_one(v: &f32) -> bool {
+        *v == 1.0
+    }
+}
+
 pub use appearance::{Appearance, AppearanceItem, Arrowhead, Dash, Effect, FillLayer, LineCap, LineJoin, StrokeAlign, StrokeLayer, WidthProfile};
 pub use drawcraft_color as color;
 pub use drawcraft_geom as geom;
diff --git a/crates/doc/src/node.rs b/crates/doc/src/node.rs
index ed139d85..e3d3fbd3 100644
--- a/crates/doc/src/node.rs
+++ b/crates/doc/src/node.rs
@@ -183,15 +183,15 @@ pub enum NodeKind {
     },
     Path {
         path: PathData,
-        #[serde(default)]
+        #[serde(default, skip_serializing_if = "crate::skip::is_default")]
         rule: FillRule,
         #[serde(default, skip_serializing_if = "Option::is_none")]
         live: Option<LiveShape>,
         /// This path acts as a clipping path inside a clip group.
-        #[serde(default)]
+        #[serde(default, skip_serializing_if = "crate::skip::is_default")]
         clipping: bool,
         /// Guide (non-printing) path.
-        #[serde(default)]
+        #[serde(default, skip_serializing_if = "crate::skip::is_default")]
         guide: bool,
     },
     /// Compound path: children are paths painted as one with the compound's appearance.
@@ -243,19 +243,19 @@ pub struct Node {
     pub id: NodeId,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub name: Option<String>,
-    #[serde(default = "yes")]
+    #[serde(default = "yes", skip_serializing_if = "crate::skip::is_true")]
     pub visible: bool,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub locked: bool,
-    #[serde(default = "one")]
+    #[serde(default = "one", skip_serializing_if = "crate::skip::is_one")]
     pub opacity: f32,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub blend: BlendMode,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub isolate: bool,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub knockout: bool,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "crate::skip::is_default")]
     pub appearance: Appearance,
     /// Opacity mask (Transparency panel). Its art lives here, outside the layer tree.
     #[serde(default, skip_serializing_if = "Option::is_none")]
diff --git a/crates/engine/src/cmd/file.rs b/crates/engine/src/cmd/file.rs
index 92008d6c..06270361 100644
--- a/crates/engine/src/cmd/file.rs
+++ b/crates/engine/src/cmd/file.rs
@@ -76,7 +76,7 @@ fn save(s: &mut Session, p: &Value) -> Result<Value> {
         .map(str::to_string)
         .or_else(|| s.active().and_then(|d| d.path.clone()))
         .ok_or_else(|| bad("document.save", "no path"))?;
-    let bytes = drawcraft_format::save(&s.doc()?.doc, true);
+    let bytes = drawcraft_format::save_file(&s.doc()?.doc);
     std::fs::write(&path, bytes).map_err(|e| EngineError::Other(format!("{path}: {e}")))?;
     let st = s.doc_mut()?;
     st.path = Some(path.clone());
@@ -87,7 +87,7 @@ fn save(s: &mut Session, p: &Value) -> Result<Value> {
 pub(crate) fn encode(s: &Session, format: &str, scale: f64, artboard: usize) -> Result<Vec<u8>> {
     let doc = &s.doc()?.doc;
     Ok(match format {
-        "drawcraft" => drawcraft_format::save(doc, true),
+        "drawcraft" => drawcraft_format::save_file(doc),
         "svg" => drawcraft_svg::export(doc, &drawcraft_svg::ExportOptions { artboard: Some(artboard), ..Default::default() }).into_bytes(),
         "pdf" => drawcraft_pdf::export(doc, &drawcraft_pdf::PdfOptions::default()).map_err(|e| EngineError::Other(e.to_string()))?,
         "png" | "jpg" | "jpeg" | "webp" => {
diff --git a/crates/format/src/lib.rs b/crates/format/src/lib.rs
index 1e4c58e6..6f3da4a2 100644
--- a/crates/format/src/lib.rs
+++ b/crates/format/src/lib.rs
@@ -16,7 +16,8 @@ use std::sync::Arc;
 use drawcraft_doc::{Document, ImageBlob};
 use serde::{Deserialize, Serialize};
 
-pub const VERSION: u32 = 1;
+/// v2: anchors as `{p: [x, y], in?, out?, kind?}` and default-valued fields omitted (v1 files still load).
+pub const VERSION: u32 = 2;
 pub const EXTENSION: &str = "drawcraft";
 
 #[derive(Debug, thiserror::Error)]
@@ -59,6 +60,16 @@ pub fn save(doc: &Document, pretty: bool) -> Vec<u8> {
     if pretty { serde_json::to_vec_pretty(&f).unwrap_or_default() } else { serde_json::to_vec(&f).unwrap_or_default() }
 }
 
+/// Documents up to this many objects are saved pretty-printed (readable, diffable); larger ones
+/// compact, where indentation would multiply the file size and slow opening down.
+pub const PRETTY_MAX_OBJECTS: usize = 2000;
+
+/// Serialize for saving to disk: pretty when small, compact when large.
+pub fn save_file(doc: &Document) -> Vec<u8> {
+    let objects: usize = doc.layers.iter().map(|l| l.count()).sum();
+    save(doc, objects <= PRETTY_MAX_OBJECTS)
+}
+
 pub fn load(bytes: &[u8]) -> Result<Document, FormatError> {
     let f: File = serde_json::from_slice(bytes).map_err(|e| FormatError::NotDrawcraft(e.to_string()))?;
     if f.format != "drawcraft" {
diff --git a/crates/geom/src/path.rs b/crates/geom/src/path.rs
index 2a23f9b5..2619421c 100644
--- a/crates/geom/src/path.rs
+++ b/crates/geom/src/path.rs
@@ -25,7 +25,9 @@ pub enum AnchorKind {
 }
 
 /// One anchor point with absolute handle positions. A handle equal to `p` means "no handle".
+/// Serialized without handles that equal `p` and without the default `kind` (smaller files).
 #[derive(Clone, Copy, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(from = "AnchorRepr", into = "AnchorRepr")]
 pub struct Anchor {
     pub p: Point,
     #[serde(rename = "in")]
@@ -36,6 +38,80 @@ pub struct Anchor {
     pub kind: AnchorKind,
 }
 
+/// Wire form of [`Anchor`]: points as `[x, y]` (format v2; `{"x", "y"}` maps from v1 files are
+/// still read), and absent handles mean "no handle" (equal to `p`).
+#[derive(Serialize, Deserialize)]
+struct AnchorRepr {
+    p: WirePoint,
+    #[serde(rename = "in", default, skip_serializing_if = "Option::is_none")]
+    h_in: Option<WirePoint>,
+    #[serde(rename = "out", default, skip_serializing_if = "Option::is_none")]
+    h_out: Option<WirePoint>,
+    #[serde(default, skip_serializing_if = "is_corner")]
+    kind: AnchorKind,
+}
+
+fn is_corner(k: &AnchorKind) -> bool {
+    *k == AnchorKind::Corner
+}
+
+impl From<AnchorRepr> for Anchor {
+    fn from(r: AnchorRepr) -> Self {
+        let p = r.p.0;
+        Self { p, h_in: r.h_in.map_or(p, |h| h.0), h_out: r.h_out.map_or(p, |h| h.0), kind: r.kind }
+    }
+}
+
+impl From<Anchor> for AnchorRepr {
+    fn from(a: Anchor) -> Self {
+        let handle = |h: Point| (h != a.p).then_some(WirePoint(h));
+        Self { p: WirePoint(a.p), h_in: handle(a.h_in), h_out: handle(a.h_out), kind: a.kind }
+    }
+}
+
+/// A point written as `[x, y]`, read from `[x, y]` or `{"x": …, "y": …}`.
+struct WirePoint(Point);
+
+impl Serialize for WirePoint {
+    fn serialize<S: serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
+        [self.0.x, self.0.y].serialize(s)
+    }
+}
+
+impl<'de> Deserialize<'de> for WirePoint {
+    fn deserialize<D: serde::Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
+        struct V;
+        impl<'de> serde::de::Visitor<'de> for V {
+            type Value = WirePoint;
+            fn expecting(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+                f.write_str("a point as [x, y] or {\"x\": x, \"y\": y}")
+            }
+            fn visit_seq<A: serde::de::SeqAccess<'de>>(self, mut a: A) -> Result<WirePoint, A::Error> {
+                let x = a.next_element()?.ok_or_else(|| serde::de::Error::invalid_length(0, &self))?;
+                let y = a.next_element()?.ok_or_else(|| serde::de::Error::invalid_length(1, &self))?;
+                Ok(WirePoint(Point::new(x, y)))
+            }
+            fn visit_map<A: serde::de::MapAccess<'de>>(self, mut a: A) -> Result<WirePoint, A::Error> {
+                let (mut x, mut y) = (None, None);
+                while let Some(k) = a.next_key::<std::borrow::Cow<'de, str>>()? {
+                    match k.as_ref() {
+                        "x" => x = Some(a.next_value()?),
+                        "y" => y = Some(a.next_value()?),
+                        _ => {
+                            a.next_value::<serde::de::IgnoredAny>()?;
+                        }
+                    }
+                }
+                Ok(WirePoint(Point::new(
+                    x.ok_or_else(|| serde::de::Error::missing_field("x"))?,
+                    y.ok_or_else(|| serde::de::Error::missing_field("y"))?,
+                )))
+            }
+        }
+        d.deserialize_any(V)
+    }
+}
+
 impl Anchor {
     /// A corner anchor without handles.
     pub fn corner(p: Point) -> Self {
@@ -342,6 +418,19 @@ mod tests {
         PathData::single(SubPath::polyline(&[Point::new(0.0, 0.0), Point::new(10.0, 0.0), Point::new(10.0, 10.0), Point::new(0.0, 10.0)], true))
     }
 
+    #[test]
+    fn anchors_serialize_compactly_and_read_v1_maps() {
+        let corner = Anchor::corner(Point::new(1.0, 2.0));
+        assert_eq!(serde_json::to_string(&corner).unwrap(), r#"{"p":[1.0,2.0]}"#);
+        let smooth = Anchor { p: Point::new(1.0, 2.0), h_in: Point::new(0.0, 2.0), h_out: Point::new(2.0, 2.0), kind: AnchorKind::Smooth };
+        let back: Anchor = serde_json::from_str(&serde_json::to_string(&smooth).unwrap()).unwrap();
+        assert_eq!(back, smooth);
+        let v1 = r#"{"p":{"x":1.0,"y":2.0},"in":{"x":0.0,"y":2.0},"out":{"x":2.0,"y":2.0},"kind":"Smooth"}"#;
+        assert_eq!(serde_json::from_str::<Anchor>(v1).unwrap(), smooth);
+        let v1_corner = r#"{"p":{"x":1.0,"y":2.0},"in":{"x":1.0,"y":2.0},"out":{"x":1.0,"y":2.0},"kind":"Corner"}"#;
+        assert_eq!(serde_json::from_str::<Anchor>(v1_corner).unwrap(), corner);
+    }
+
     #[test]
     fn square_bounds_and_area() {
         let p = square();
diff --git a/crates/mcp/src/headless.rs b/crates/mcp/src/headless.rs
index 55ffd476..e0ea0b4f 100644
--- a/crates/mcp/src/headless.rs
+++ b/crates/mcp/src/headless.rs
@@ -245,7 +245,7 @@ impl Headless {
     pub fn save(&mut self, p: &Value) -> Result<Value, String> {
         let st = self.session.active().ok_or("no document")?;
         let path = s(p, "path").map(str::to_string).or_else(|| st.path.clone()).ok_or("missing `path` (document was never saved)")?;
-        let bytes = drawcraft_format::save(&st.doc, true);
+        let bytes = drawcraft_format::save_file(&st.doc);
         std::fs::write(&path, bytes).map_err(|e| format!("write {path}: {e}"))?;
         if let Some(st) = self.session.active_mut() {
             st.path = Some(path.clone());
@@ -271,7 +271,7 @@ impl Headless {
                 let scale = p.get("scale").and_then(Value::as_f64).unwrap_or(1.0).clamp(0.01, 16.0);
                 self.renderer.render_region(&doc, r, scale, false).to_png()
             }
-            "drawcraft" => drawcraft_format::save(&doc, true),
+            "drawcraft" => drawcraft_format::save_file(&doc),
             // pdf, jpg, webp…: the engine's exporter (same bytes as the app).
             other => {
                 let params = json!({"path": path, "format": other, "scale": p.get("scale"), "artboard": p.get("artboard")});
diff --git a/crates/ui-egui/src/io.rs b/crates/ui-egui/src/io.rs
index 0869b1f9..05500db5 100644
--- a/crates/ui-egui/src/io.rs
+++ b/crates/ui-egui/src/io.rs
@@ -157,7 +157,7 @@ pub fn save(app: &mut DrawcraftApp, path: Option<String>, save_as: bool) -> Resu
             app.services.pick_save.as_mut().and_then(|f| f(&s)).ok_or("cancelled")?
         }
     };
-    let bytes = drawcraft_format::save(&app.session.active().unwrap().doc, true);
+    let bytes = drawcraft_format::save_file(&app.session.active().unwrap().doc);
     write_out(app, &path, &bytes)?;
     if let Some(st) = app.session.active_mut() {
         st.path = Some(path.clone());