diff --git a/AGENTS.md b/AGENTS.md
index 53a2a07d2..f5f688947 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -6,6 +6,8 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for how to open a pull request (CLA, dev
 
 Run `make download-v8` once first: it fetches the prebuilt V8 archive into `.lp-cache/`, which `build.zig` picks up automatically. Without it every build compiles V8 from source (10+ minutes).
 
+The C and Rust dependencies are built in ReleaseFast whatever `-Doptimize` is, so debug and release builds share them. Pass `ZIGFLAGS=-Ddebug_deps` to step into a dependency with a debugger.
+
 ```bash
 make test                                       # Run all tests
 make test F="server"                            # Filter by substring
diff --git a/Makefile b/Makefile
index 5d3eb4369..a1466144c 100644
--- a/Makefile
+++ b/Makefile
@@ -3,8 +3,6 @@
 
 ZIG := zig
 BC := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
-# tikv-jemalloc-sys's nested make can't parse inherited "-- F=..." overrides
-MAKEOVERRIDES =
 # option test filter make test F="server"
 F=
 
diff --git a/build.zig b/build.zig
index 42a58eba2..8b8b41ada 100644
--- a/build.zig
+++ b/build.zig
@@ -72,6 +72,15 @@ pub fn build(b: *Build) !void {
         .glibc_version = devFastGlibcVersion(b),
     }) else requested_target;
 
+    // Dependencies never follow -Doptimize, and they build for the requested
+    // target rather than the dev_fast bundled-CRT query, so debug and release
+    // builds share one set of dependency objects in the cache.
+    const debug_deps = b.option(bool, "debug_deps", "Build the C and Rust dependencies in Debug instead of ReleaseFast") orelse false;
+    const deps: Deps = .{
+        .target = requested_target,
+        .optimize = if (debug_deps) .Debug else .ReleaseFast,
+    };
+
     // Without an explicit -Dprebuilt_v8_path, pick up whatever `make
     // download-v8` cached rather than building V8 from source.
     const prebuilt_v8_path = prebuilt_v8_path_option orelse if (enable_tsan or enable_asan) null else findPrebuiltV8(b, target, dev_fast);
@@ -120,12 +129,12 @@ pub fn build(b: *Build) !void {
     const v8_archive: ?Build.LazyPath = if (prebuilt_v8_path) |path| .{ .cwd_relative = path } else null;
     const v8_for_link = if (orderfile != null and v8_archive != null and !shared_v8) markHotSections(b, v8_archive.?) else v8_archive;
     linkV8(b, lightpanda_module, enable_asan, enable_tsan, v8_for_link, shared_v8);
-    linkCurl(b, lightpanda_module, enable_tsan, orderfile != null);
-    linkRust(b, lightpanda_module);
+    linkCurl(b, lightpanda_module, deps, enable_tsan, orderfile != null);
+    linkRust(b, lightpanda_module, deps);
     linkZenai(b, lightpanda_module);
     linkIsocline(b, lightpanda_module);
-    linkSqlite(b, lightpanda_module, enable_csan, enable_tsan, orderfile != null);
-    linkPcre2(b, lightpanda_module, enable_csan, enable_tsan, orderfile != null);
+    linkSqlite(b, lightpanda_module, deps, enable_csan, enable_tsan, orderfile != null);
+    linkPcre2(b, lightpanda_module, deps, enable_csan, enable_tsan, orderfile != null);
 
     // Check compilation
     const check = b.step("check", "Check if lightpanda compiles");
@@ -211,6 +220,11 @@ pub fn build(b: *Build) !void {
     }
 }
 
+const Deps = struct {
+    target: Build.ResolvedTarget,
+    optimize: std.builtin.OptimizeMode,
+};
+
 const ExeConfig = struct {
     check: *Build.Step,
     lightpanda_module: *Build.Module,
@@ -377,14 +391,14 @@ fn linkV8(
     mod.addImport("v8", dep.module("v8"));
 }
 
-fn linkRust(b: *Build, mod: *Build.Module) void {
-    const is_debug = mod.optimize.? == .Debug;
+fn linkRust(b: *Build, mod: *Build.Module, deps: Deps) void {
+    // Cargo's "dev" profile writes to target/debug.
+    const profile, const out_subdir = if (deps.optimize == .Debug) .{ "dev", "debug" } else .{ "release", "release" };
 
     // One cargo workspace, one staticlib (src/rust/Cargo.toml explains why).
     const exec_cargo = b.addSystemCommand(&.{
         "cargo",           "build",
-        "--profile",       if (is_debug) "dev" else "release",
-        "--features",      if (is_debug) "memstats" else "",
+        "--profile",       profile,
         "--manifest-path", "src/rust/ffi/Cargo.toml",
     });
 
@@ -397,17 +411,13 @@ fn linkRust(b: *Build, mod: *Build.Module) void {
     // still surfaces the captured output.
     _ = exec_cargo.captureStdErr(.{});
 
-    // don't let cargo's progress report (sent to stderr) cause Zig's build to
-    // print a 'failed command: ...' message. (non-zero status still outputs the error)
-    _ = exec_cargo.captureStdErr(.{});
-
     // TODO: We can prefer `--artifact-dir` once it become stable.
     const out_dir = exec_cargo.addPrefixedOutputDirectoryArg("--target-dir=", "rust");
 
     const rust_step = b.step("rust", "Build the Rust staticlib (requires cargo)");
     rust_step.dependOn(&exec_cargo.step);
 
-    const obj = out_dir.path(b, if (is_debug) "debug" else "release").path(b, "liblightpanda_ffi.a");
+    const obj = out_dir.path(b, out_subdir).path(b, "liblightpanda_ffi.a");
     mod.addObjectFile(obj);
 }
 
@@ -429,10 +439,10 @@ fn addDirInputs(b: *Build, run: *Build.Step.Run, root: []const u8, skip_dir: []c
     }
 }
 
-fn linkSqlite(b: *Build, mod: *Build.Module, enable_csan: ?std.zig.SanitizeC, is_tsan: bool, section: bool) void {
+fn linkSqlite(b: *Build, mod: *Build.Module, deps: Deps, enable_csan: ?std.zig.SanitizeC, is_tsan: bool, section: bool) void {
     const dep = b.dependency("sqlite3", .{
-        .target = mod.resolved_target.?,
-        .optimize = mod.optimize.?,
+        .target = deps.target,
+        .optimize = deps.optimize,
     });
 
     const lib = sectionize(dep.artifact("sqlite3"), section);
@@ -487,10 +497,10 @@ fn linkSqlite(b: *Build, mod: *Build.Module, enable_csan: ?std.zig.SanitizeC, is
     mod.addImport("sqlite3", translate_c.createModule());
 }
 
-fn linkPcre2(b: *Build, mod: *Build.Module, enable_csan: ?std.zig.SanitizeC, is_tsan: bool, section: bool) void {
+fn linkPcre2(b: *Build, mod: *Build.Module, deps: Deps, enable_csan: ?std.zig.SanitizeC, is_tsan: bool, section: bool) void {
     const dep = b.dependency("pcre2", .{
-        .target = mod.resolved_target.?,
-        .optimize = mod.optimize.?,
+        .target = deps.target,
+        .optimize = deps.optimize,
         .linkage = .static,
     });
 
@@ -508,34 +518,32 @@ fn linkPcre2(b: *Build, mod: *Build.Module, enable_csan: ?std.zig.SanitizeC, is_
     mod.addImport("pcre2", translate_c.createModule());
 }
 
-fn linkCurl(b: *Build, mod: *Build.Module, is_tsan: bool, section: bool) void {
-    const target = mod.resolved_target.?;
-
-    const curl = buildCurl(b, target, mod.optimize.?, is_tsan, section);
+fn linkCurl(b: *Build, mod: *Build.Module, deps: Deps, is_tsan: bool, section: bool) void {
+    const curl = buildCurl(b, deps.target, deps.optimize, is_tsan, section);
     mod.linkLibrary(curl);
 
     const dep = b.dependency("curl", .{});
     const translate_c = b.addTranslateC(.{
         .root_source_file = dep.path("include/curl/curl.h"),
-        .target = target,
+        .target = mod.resolved_target.?,
         .optimize = mod.optimize.?,
     });
     translate_c.addIncludePath(dep.path("include"));
     mod.addImport("curl", translate_c.createModule());
 
-    const zlib = buildZlib(b, target, mod.optimize.?, is_tsan, section);
+    const zlib = buildZlib(b, deps.target, deps.optimize, is_tsan, section);
     curl.root_module.linkLibrary(zlib);
 
-    const brotli = buildBrotli(b, target, mod.optimize.?, is_tsan, section);
+    const brotli = buildBrotli(b, deps.target, deps.optimize, is_tsan, section);
     for (brotli) |lib| curl.root_module.linkLibrary(lib);
 
-    const nghttp2 = buildNghttp2(b, target, mod.optimize.?, is_tsan, section);
+    const nghttp2 = buildNghttp2(b, deps.target, deps.optimize, is_tsan, section);
     curl.root_module.linkLibrary(nghttp2);
 
-    const boringssl = buildBoringSsl(b, target, mod.optimize.?, section);
+    const boringssl = buildBoringSsl(b, deps.target, deps.optimize, section);
     for (boringssl) |lib| curl.root_module.linkLibrary(lib);
 
-    if (target.result.os.tag == .macos) {
+    if (deps.target.result.os.tag == .macos) {
         // needed for proxying on mac
         const framework_path = if (b.sysroot) |sysroot|
             b.pathJoin(&.{ sysroot, "System/Library/Frameworks" })
diff --git a/src/browser/parser/html5ever.zig b/src/browser/parser/html5ever.zig
index 3b7cf3223..4d1a29776 100644
--- a/src/browser/parser/html5ever.zig
+++ b/src/browser/parser/html5ever.zig
@@ -96,13 +96,6 @@ pub extern "c" fn html5ever_parse_fragment(
 pub extern "c" fn html5ever_attribute_iterator_next(ctx: *anyopaque) Nullable(Attribute);
 pub extern "c" fn html5ever_attribute_iterator_count(ctx: *anyopaque) usize;
 
-pub extern "c" fn html5ever_get_memory_usage() MemoryUsage;
-
-const MemoryUsage = extern struct {
-    resident: usize,
-    allocated: usize,
-};
-
 // Streaming parser API
 pub extern "c" fn html5ever_streaming_parser_create(
     doc: *anyopaque,
diff --git a/src/rust/Cargo.lock b/src/rust/Cargo.lock
index 455440f4f..4305378bf 100644
--- a/src/rust/Cargo.lock
+++ b/src/rust/Cargo.lock
@@ -52,16 +52,6 @@ dependencies = [
  "syn 3.0.3",
 ]
 
-[[package]]
-name = "cc"
-version = "1.2.39"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e1354349954c6fc9cb0deab020f27f783cf0b604e8bb754dc4658ecf0d29c35f"
-dependencies = [
- "find-msvc-tools",
- "shlex",
-]
-
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -112,12 +102,6 @@ dependencies = [
  "simd-adler32",
 ]
 
-[[package]]
-name = "find-msvc-tools"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ced73b1dacfc750a6db6c0a0c3a3853c8b41997e2e2c563dc90804ae6867959"
-
 [[package]]
 name = "flate2"
 version = "1.1.9"
@@ -358,8 +342,6 @@ version = "0.1.0"
 dependencies = [
  "lightpanda-html5ever",
  "lightpanda-render",
- "tikv-jemalloc-ctl",
- "tikv-jemallocator",
 ]
 
 [[package]]
@@ -513,12 +495,6 @@ dependencies = [
  "icu_properties",
 ]
 
-[[package]]
-name = "paste"
-version = "1.0.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
-
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -668,12 +644,6 @@ dependencies = [
  "syn 3.0.3",
 ]
 
-[[package]]
-name = "shlex"
-version = "1.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
-
 [[package]]
 name = "simd-adler32"
 version = "0.3.10"
@@ -782,37 +752,6 @@ dependencies = [
  "utf-8",
 ]
 
-[[package]]
-name = "tikv-jemalloc-ctl"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "661f1f6a57b3a36dc9174a2c10f19513b4866816e13425d3e418b11cc37bc24c"
-dependencies = [
- "libc",
- "paste",
- "tikv-jemalloc-sys",
-]
-
-[[package]]
-name = "tikv-jemalloc-sys"
-version = "0.6.1+5.3.0-1-ge13ca993e8ccb9ba9847cc330696e02839f328f7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd8aa5b2ab86a2cefa406d889139c162cbb230092f7d1d7cbc1716405d852a3b"
-dependencies = [
- "cc",
- "libc",
-]
-
-[[package]]
-name = "tikv-jemallocator"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0359b4327f954e0567e69fb191cf1436617748813819c94b8cd4a431422d053a"
-dependencies = [
- "libc",
- "tikv-jemalloc-sys",
-]
-
 [[package]]
 name = "tiny-skia"
 version = "0.12.0"
diff --git a/src/rust/ffi/Cargo.toml b/src/rust/ffi/Cargo.toml
index 9765ad866..3030ac768 100644
--- a/src/rust/ffi/Cargo.toml
+++ b/src/rust/ffi/Cargo.toml
@@ -11,8 +11,3 @@ crate-type = ["staticlib"]
 [dependencies]
 lightpanda-html5ever = { path = "../html5ever" }
 lightpanda-render = { path = "../render" }
-tikv-jemallocator = { version = "0.6.1", features = ["stats"], optional = true }
-tikv-jemalloc-ctl = { version = "0.6.1", features = ["stats"], optional = true }
-
-[features]
-memstats = ["dep:tikv-jemallocator", "dep:tikv-jemalloc-ctl"]
diff --git a/src/rust/ffi/lib.rs b/src/rust/ffi/lib.rs
index f0b051be7..42d88da87 100644
--- a/src/rust/ffi/lib.rs
+++ b/src/rust/ffi/lib.rs
@@ -18,33 +18,7 @@
 
 //! The one staticlib Zig links. Domain crates define their own `extern "C"`
 //! entry points; `extern crate` is what pulls an otherwise-unreferenced crate
-//! into the archive (edition 2018+ drops unused `--extern` deps). Process-wide
-//! concerns (the allocator) live here, not in a domain crate.
+//! into the archive (edition 2018+ drops unused `--extern` deps).
 
 extern crate lightpanda_html5ever;
 extern crate lightpanda_render;
-
-#[cfg(feature = "memstats")]
-#[global_allocator]
-static GLOBAL: tikv_jemallocator::Jemalloc = tikv_jemallocator::Jemalloc;
-
-#[cfg(feature = "memstats")]
-#[repr(C)]
-pub struct Memory {
-    pub resident: usize,
-    pub allocated: usize,
-}
-
-#[cfg(feature = "memstats")]
-#[no_mangle]
-pub extern "C" fn html5ever_get_memory_usage() -> Memory {
-    use tikv_jemalloc_ctl::{epoch, stats};
-
-    // many statistics are cached and only updated when the epoch is advanced.
-    let _ = epoch::advance();
-
-    Memory {
-        resident: stats::resident::read().unwrap_or(0),
-        allocated: stats::allocated::read().unwrap_or(0),
-    }
-}