diff --git a/.github/workflows/codspeed.yml b/.github/workflows/codspeed.yml
new file mode 100644
index 0000000..dd84b6d
--- /dev/null
+++ b/.github/workflows/codspeed.yml
@@ -0,0 +1,53 @@
+name: CodSpeed
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  # `workflow_dispatch` allows CodSpeed to trigger backtest
+  # performance analysis in order to generate initial data.
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  id-token: write
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  codspeed:
+    name: Run benchmarks
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: src-tauri
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Linux dependencies
+        working-directory: .
+        run: >
+          sudo apt-get update &&
+          sudo apt-get install -y
+          libwebkit2gtk-4.1-dev
+          libappindicator3-dev
+          librsvg2-dev
+          patchelf
+
+      - name: Setup rust toolchain, cache and cargo-codspeed binary
+        uses: moonrepo/setup-rust@v0
+        with:
+          channel: stable
+          cache-target: release
+          bins: cargo-codspeed
+
+      - name: Build the benchmark target(s)
+        run: cargo codspeed build
+
+      - name: Run the benchmarks
+        uses: CodSpeedHQ/action@v4
+        with:
+          mode: simulation
+          run: cd src-tauri && cargo codspeed run
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c0da141..35e9f89 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **CodSpeed performance benchmarks** (CI): new `domain_benchmarks` Criterion harness in `src-tauri/benches/domain_benchmarks.rs` exercising the pure `domain::model::config` helpers (`apply_patch`, `normalize_link_check_parallelism`, `normalize_max_concurrent`). Wired through a new `.github/workflows/codspeed.yml` workflow that runs the benches under CodSpeed on every PR, providing automated perf-regression tracking for the domain layer. `criterion` + `codspeed-criterion-compat` added as dev-dependencies; `[[bench]]` target declared with `harness = false` so Criterion drives the run.
+
 - **CI hardening** (scope `ci`): new GitHub Actions jobs `secrets-scan` (rejects `.env`/`.pem`/`.key`/etc. tracked files plus `AKIA*`/`sk-ant-*`/`ghp_*`/`AIza*` API key patterns in tracked content), `forbidden-tools` (rejects `pnpm-lock.yaml`/`yarn.lock`, `.eslintrc*`/`biome.json*`/`.prettierrc*` configs, and any `#[allow(dead_code|unused|...)]` / `@ts-ignore` / `@ts-expect-error` / `oxlint-disable` comment), and `changelog-check` (PR-only — fails when `*.rs` / `*.ts` / `*.tsx` change without a matching `CHANGELOG.md` edit). Existing `cargo audit` swapped for `cargo deny check` covering advisories + licenses + bans + sources via the new `deny.toml`. Frontend job now runs `oxfmt --check`, `knip --reporter compact`, and uploads `coverage/` as an artifact. New `mutants.yml` workflow runs `cargo mutants --in-diff` on PRs touching `src-tauri/**` and a 4-shard nightly sweep on `main`.
 - **Release verification** (scope `ci`): new `verify-tag` job in `release.yml` blocks the build matrix when `Cargo.toml`, `package.json`, the pushed tag, and the `CHANGELOG.md` section are out of sync.
 - **Hook hardening** (scope `ci`): pre-commit gains `oxfmt --check` (scoped via new `.oxfmtignore` to keep `src-tauri/gen/`, `contrib/`, `registry/`, `*.md` untouched), `scripts/no-secrets.sh` (file-pattern + diff-content scan), `scripts/no-manual-deps.sh` (rejects manual `Cargo.toml` / `package.json` dep edits without an updated lock — enforces `cargo add` / `npm install`), and `changelog-updated`. Pre-push gains `cargo deny check licenses bans advisories` and `knip --reporter compact`. New `knip.json` keeps `files` / `dependencies` / `unlisted` / `binaries` / `unresolved` as `error` and demotes `exports` / `types` / `nsExports` / `nsTypes` / `duplicates` / `enumMembers` to `warn` for backwards-compatible adoption. `src-tauri/.cargo/mutants.toml` excludes the binary entrypoint, `build.rs`, `tests/**`, and the SQLite migrations from cargo-mutants and bumps `timeout_multiplier` to 2.0 / `minimum_test_timeout` to 60s to absorb Tauri/sea-orm/extism cold-build latency. `package.json` adds `knip ^6.11` and `oxfmt ^0.47` as devDependencies.
diff --git a/README.md b/README.md
index 4593ad8..22cda1a 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,7 @@
 [![Built with Tauri](https://img.shields.io/badge/built%20with-Tauri%202-24c8db?logo=tauri)](https://tauri.app)
 [![Rust](https://img.shields.io/badge/rust-1.95-orange?logo=rust)](src-tauri/Cargo.toml)
 [![CI](https://github.com/mpiton/vortex/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/mpiton/vortex/actions/workflows/ci.yml)
+[![CodSpeed](https://img.shields.io/endpoint?url=https://codspeed.io/badge.json)](https://codspeed.io/mpiton/vortex?utm_source=badge)
 
 Open-source desktop download manager — successor to JDownloader. Tauri 2 + Rust backend + React 19 frontend, hexagonal architecture, CQRS, WASM plugin system (Extism).
 
diff --git a/src-tauri/Cargo.lock b/src-tauri/Cargo.lock
index 1768fad..e39917d 100644
--- a/src-tauri/Cargo.lock
+++ b/src-tauri/Cargo.lock
@@ -114,6 +114,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "anes"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b46cbb362ab8752921c97e041f5e366ee6297bd428a31275b9fcf1e380f7299"
+
 [[package]]
 name = "anstream"
 version = "1.0.0"
@@ -150,7 +156,7 @@ version = "1.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
 dependencies = [
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -161,7 +167,7 @@ checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
 dependencies = [
  "anstyle",
  "once_cell_polyfill",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -170,6 +176,15 @@ version = "1.0.102"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 
+[[package]]
+name = "approx"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cab112f0a86d568ea0e627cc1d6be74a1e9cd55214684db5561995f6dad897c6"
+dependencies = [
+ "num-traits",
+]
+
 [[package]]
 name = "arbitrary"
 version = "1.4.2"
@@ -832,6 +847,12 @@ dependencies = [
  "toml 0.9.12+spec-1.1.0",
 ]
 
+[[package]]
+name = "cast"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
+
 [[package]]
 name = "cbc"
 version = "0.1.2"
@@ -933,6 +954,33 @@ dependencies = [
  "windows-link 0.2.1",
 ]
 
+[[package]]
+name = "ciborium"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42e69ffd6f0917f5c029256a24d0161db17cea3997d185db0d35926308770f0e"
+dependencies = [
+ "ciborium-io",
+ "ciborium-ll",
+ "serde",
+]
+
+[[package]]
+name = "ciborium-io"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05afea1e0a06c9be33d539b876f1ce3692f4afea2cb41f740e7743225ed1c757"
+
+[[package]]
+name = "ciborium-ll"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57663b653d948a338bfb3eeba9bb2fd5fcfaecb9e199e87e1eda4d9e8b240fd9"
+dependencies = [
+ "ciborium-io",
+ "half",
+]
+
 [[package]]
 name = "cipher"
 version = "0.4.4"
@@ -1016,12 +1064,80 @@ dependencies = [
  "thiserror 2.0.18",
 ]
 
+[[package]]
+name = "codspeed"
+version = "4.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7ce4a32373a5c84f4fa785099b300b9b1796311abc122b9eb62c65fa615145d"
+dependencies = [
+ "anyhow",
+ "cc",
+ "colored",
+ "getrandom 0.2.17",
+ "glob",
+ "libc",
+ "nix 0.31.2",
+ "serde",
+ "serde_json",
+ "statrs",
+]
+
+[[package]]
+name = "codspeed-criterion-compat"
+version = "4.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f5557c4e023f427ba208b849193c51c2ebd40534828490cd3f5f7f7fc0284ce5"
+dependencies = [
+ "clap",
+ "codspeed",
+ "codspeed-criterion-compat-walltime",
+ "colored",
+ "regex",
+]
+
+[[package]]
+name = "codspeed-criterion-compat-walltime"
+version = "4.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43ac19f0a5c3542301e9d011d658f93c3f550698ec8ba7d7c072692e7924c401"
+dependencies = [
+ "anes",
+ "cast",
+ "ciborium",
+ "clap",
+ "codspeed",
+ "criterion-plot",
+ "is-terminal",
+ "itertools 0.10.5",
+ "num-traits",
+ "once_cell",
+ "oorandom",
+ "plotters",
+ "rayon",
+ "regex",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "tinytemplate",
+ "walkdir",
+]
+
 [[package]]
 name = "colorchoice"
 version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
 
+[[package]]
+name = "colored"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "117725a109d387c937a1533ce01b450cbde6b88abceea8473c4d7a85853cda3c"
+dependencies = [
+ "lazy_static",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "combine"
 version = "4.6.7"
@@ -1318,6 +1434,16 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "criterion-plot"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b50826342786a51a89e2da3a28f1c32b06e387201bc2d19791f622c673706b1"
+dependencies = [
+ "cast",
+ "itertools 0.10.5",
+]
+
 [[package]]
 name = "crossbeam-channel"
 version = "0.5.15"
@@ -1689,7 +1815,7 @@ dependencies = [
  "libc",
  "option-ext",
  "redox_users 0.5.2",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -1938,7 +2064,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -3301,12 +3427,32 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "is-terminal"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3640c1c38b8e4e43584d8df18be5fc6b0aa314ce6ebf51b53313d4306cca8e46"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
 
+[[package]]
+name = "itertools"
+version = "0.10.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itertools"
 version = "0.14.0"
@@ -3685,7 +3831,7 @@ version = "1.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c0aeb26bf5e836cc1c341c8106051b573f1766dfa05aa87f0b98be5e51b02303"
 dependencies = [
- "nix",
+ "nix 0.29.0",
  "serde",
  "winapi",
 ]
@@ -3963,6 +4109,18 @@ dependencies = [
  "memoffset",
 ]
 
+[[package]]
+name = "nix"
+version = "0.31.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d6d0705320c1e6ba1d912b5e37cf18071b6c2e9b7fa8215a1e8a7651966f5d3"
+dependencies = [
+ "bitflags 2.11.0",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+]
+
 [[package]]
 name = "nodrop"
 version = "0.1.14"
@@ -4025,7 +4183,7 @@ version = "0.50.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
 dependencies = [
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -4283,6 +4441,12 @@ version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
 
+[[package]]
+name = "oorandom"
+version = "11.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6790f58c7ff633d8771f42965289203411a5e5c68388703c06e14f24770b41e"
+
 [[package]]
 name = "opaque-debug"
 version = "0.3.1"
@@ -4365,7 +4529,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7d8fae84b431384b68627d0f9b3b1245fcf9f46f6c0e3dc902e9dce64edd1967"
 dependencies = [
  "libc",
- "windows-sys 0.45.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -4775,6 +4939,34 @@ dependencies = [
  "time",
 ]
 
+[[package]]
+name = "plotters"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aeb6f403d7a4911efb1e33402027fc44f29b5bf6def3effcc22d7bb75f2b747"
+dependencies = [
+ "num-traits",
+ "plotters-backend",
+ "plotters-svg",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "plotters-backend"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df42e13c12958a16b3f7f4386b9ab1f3e7933914ecea48da7139435263a4172a"
+
+[[package]]
+name = "plotters-svg"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51bae2ac328883f7acdfea3d66a7c35751187f870bc81f94563733a154d7a670"
+dependencies = [
+ "plotters-backend",
+]
+
 [[package]]
 name = "png"
 version = "0.17.16"
@@ -5016,7 +5208,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "27c6023962132f4b30eb4c172c91ce92d933da334c59c23cddee82358ddafb0b"
 dependencies = [
  "anyhow",
- "itertools",
+ "itertools 0.14.0",
  "proc-macro2",
  "quote",
  "syn 2.0.117",
@@ -5672,7 +5864,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys 0.12.1",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -5741,7 +5933,7 @@ dependencies = [
  "security-framework",
  "security-framework-sys",
  "webpki-root-certs",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -6424,7 +6616,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3a766e1110788c36f4fa1c2b71b387a7815aa65f88ce0229841826633d93723e"
 dependencies = [
  "libc",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -6714,6 +6906,16 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 
+[[package]]
+name = "statrs"
+version = "0.18.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a3fe7c28c6512e766b0874335db33c94ad7b8f9054228ae1c2abd47ce7d335e"
+dependencies = [
+ "approx",
+ "num-traits",
+]
+
 [[package]]
 name = "string_cache"
 version = "0.8.9"
@@ -7353,7 +7555,7 @@ dependencies = [
  "getrandom 0.4.2",
  "once_cell",
  "rustix 1.1.4",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -7491,6 +7693,16 @@ dependencies = [
  "zerovec",
 ]
 
+[[package]]
+name = "tinytemplate"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4d6b5f19ff7664e8c98d03e2139cb510db9b0a60b55f8e8709b689d939b6bc"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "tinyvec"
 version = "1.11.0"
@@ -7861,7 +8073,7 @@ checksum = "f2f6fb2847f6742cd76af783a2a2c49e9375d0a111c7bef6f71cd9e738c72d6e"
 dependencies = [
  "memoffset",
  "tempfile",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -8130,6 +8342,7 @@ dependencies = [
  "bincode",
  "bytes",
  "bzip2",
+ "codspeed-criterion-compat",
  "dashmap",
  "digest 0.11.2",
  "dirs",
@@ -8606,7 +8819,7 @@ dependencies = [
  "cranelift-frontend",
  "cranelift-native",
  "gimli",
- "itertools",
+ "itertools 0.14.0",
  "log",
  "object",
  "pulley-interpreter",
@@ -9042,7 +9255,7 @@ version = "0.1.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
 dependencies = [
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
diff --git a/src-tauri/Cargo.toml b/src-tauri/Cargo.toml
index 1f669fd..941b0c8 100644
--- a/src-tauri/Cargo.toml
+++ b/src-tauri/Cargo.toml
@@ -69,5 +69,10 @@ tauri-plugin-pilot = "0.4.0"
 windows-sys = { version = "0.59", features = ["Win32_Storage_FileSystem"] }
 
 [dev-dependencies]
+criterion = { version = "4.6.0", package = "codspeed-criterion-compat" }
 tempfile = "3.27.0"
 wiremock = "0.6.5"
+
+[[bench]]
+name = "domain_benchmarks"
+harness = false
diff --git a/src-tauri/benches/domain_benchmarks.rs b/src-tauri/benches/domain_benchmarks.rs
new file mode 100644
index 0000000..13bf827
--- /dev/null
+++ b/src-tauri/benches/domain_benchmarks.rs
@@ -0,0 +1,302 @@
+use criterion::{Criterion, black_box, criterion_group, criterion_main};
+use vortex_lib::domain::model::config::{
+    apply_patch, normalize_link_check_parallelism, normalize_max_concurrent,
+};
+use vortex_lib::domain::model::link::LinkStatus;
+use vortex_lib::domain::model::{
+    AppConfig, ChecksumAlgorithm, ConfigPatch, Download, DownloadId, Priority, Segment, Url,
+};
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+fn make_download() -> Download {
+    let url = Url::new("https://cdn.example.com/releases/v2.0/archive.tar.gz").unwrap();
+    Download::new(
+        DownloadId(1),
+        url,
+        "archive.tar.gz".to_string(),
+        "/tmp".to_string(),
+    )
+}
+
+// ---------------------------------------------------------------------------
+// URL parsing
+// ---------------------------------------------------------------------------
+
+fn bench_url_parsing(c: &mut Criterion) {
+    let mut group = c.benchmark_group("url_parsing");
+
+    group.bench_function("simple_https", |b| {
+        b.iter(|| Url::new(black_box("https://example.com/file.zip")))
+    });
+
+    group.bench_function("complex_with_port_and_path", |b| {
+        b.iter(|| {
+            Url::new(black_box(
+                "https://cdn.example.com:8443/releases/v2.0/archive.tar.gz?token=abc123#section",
+            ))
+        })
+    });
+
+    group.bench_function("with_userinfo", |b| {
+        b.iter(|| Url::new(black_box("https://user:pass@cdn.example.com/file.bin")))
+    });
+
+    group.bench_function("ftp_scheme", |b| {
+        b.iter(|| Url::new(black_box("ftp://mirror.example.org/pub/release.iso")))
+    });
+
+    group.finish();
+}
+
+// ---------------------------------------------------------------------------
+// Download state machine
+// ---------------------------------------------------------------------------
+
+fn bench_download_state_machine(c: &mut Criterion) {
+    let mut group = c.benchmark_group("download_state_machine");
+
+    group.bench_function("create_new", |b| {
+        b.iter(|| {
+            let url = Url::new("https://example.com/file.zip").unwrap();
+            black_box(Download::new(
+                DownloadId(1),
+                url,
+                "file.zip".to_string(),
+                "/tmp".to_string(),
+            ))
+        })
+    });
+
+    group.bench_function("full_lifecycle", |b| {
+        b.iter(|| {
+            let mut d = make_download();
+            let _ = d.start();
+            let _ = d.pause();
+            let _ = d.resume();
+            let _ = d.complete();
+            black_box(&d);
+        })
+    });
+
+    group.bench_function("start_and_fail_retry_cycle", |b| {
+        b.iter(|| {
+            let mut d = make_download().with_max_retries(3);
+            let _ = d.start();
+            let _ = d.fail("network timeout".to_string());
+            let _ = d.retry();
+            let _ = d.start();
+            let _ = d.fail("connection reset".to_string());
+            let _ = d.retry();
+            black_box(&d);
+        })
+    });
+
+    group.bench_function("progress_percentage", |b| {
+        let mut d = make_download();
+        d.set_file_size(10_000_000);
+        d.update_progress(7_500_000);
+        b.iter(|| black_box(d.progress_percentage()))
+    });
+
+    group.bench_function("checksum_workflow", |b| {
+        b.iter(|| {
+            let mut d = make_download()
+                .with_expected_checksum(
+                    "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855".to_string(),
+                )
+                .unwrap();
+            let _ = d.start();
+            let _ = d.start_checking();
+            let _ = d.record_checksum_match(
+                ChecksumAlgorithm::Sha256,
+                "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855".to_string(),
+            );
+            black_box(&d);
+        })
+    });
+
+    group.finish();
+}
+
+// ---------------------------------------------------------------------------
+// Segment operations
+// ---------------------------------------------------------------------------
+
+fn bench_segment_operations(c: &mut Criterion) {
+    let mut group = c.benchmark_group("segment_operations");
+
+    group.bench_function("create_new", |b| {
+        b.iter(|| black_box(Segment::new(1, DownloadId(10), 0, 10_485_760)))
+    });
+
+    group.bench_function("full_lifecycle", |b| {
+        b.iter(|| {
+            let mut s = Segment::new(1, DownloadId(10), 0, 10_485_760);
+            let _ = s.start();
+            s.update_progress(5_000_000);
+            let _ = s.complete();
+            black_box(&s);
+        })
+    });
+
+    group.bench_function("split", |b| {
+        b.iter(|| {
+            let mut s = Segment::new(1, DownloadId(10), 0, 10_485_760);
+            let _ = s.start();
+            s.update_progress(2_000_000);
+            let _ = s.split(5_242_880, 42);
+            black_box(&s);
+        })
+    });
+
+    group.bench_function("error_and_reset_cycle", |b| {
+        b.iter(|| {
+            let mut s = Segment::new(1, DownloadId(10), 0, 10_485_760);
+            let _ = s.start();
+            s.update_progress(1_000_000);
+            let _ = s.fail("timeout".to_string());
+            let _ = s.reset();
+            let _ = s.start();
+            let _ = s.complete();
+            black_box(&s);
+        })
+    });
+
+    group.finish();
+}
+
+// ---------------------------------------------------------------------------
+// Checksum detection
+// ---------------------------------------------------------------------------
+
+fn bench_checksum_detection(c: &mut Criterion) {
+    let mut group = c.benchmark_group("checksum_detection");
+
+    group.bench_function("detect_sha256", |b| {
+        b.iter(|| {
+            ChecksumAlgorithm::detect_from_hex(black_box(
+                "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+            ))
+        })
+    });
+
+    group.bench_function("detect_md5", |b| {
+        b.iter(|| ChecksumAlgorithm::detect_from_hex(black_box("d41d8cd98f00b204e9800998ecf8427e")))
+    });
+
+    group.bench_function("reject_invalid", |b| {
+        b.iter(|| ChecksumAlgorithm::detect_from_hex(black_box("not-a-valid-hex-string")))
+    });
+
+    group.finish();
+}
+
+// ---------------------------------------------------------------------------
+// Link status
+// ---------------------------------------------------------------------------
+
+fn bench_link_status(c: &mut Criterion) {
+    let mut group = c.benchmark_group("link_status");
+
+    group.bench_function("from_status_code_200", |b| {
+        b.iter(|| LinkStatus::from_status_code(black_box(200)))
+    });
+
+    group.bench_function("from_status_code_404", |b| {
+        b.iter(|| LinkStatus::from_status_code(black_box(404)))
+    });
+
+    group.bench_function("from_status_code_500", |b| {
+        b.iter(|| LinkStatus::from_status_code(black_box(500)))
+    });
+
+    group.finish();
+}
+
+// ---------------------------------------------------------------------------
+// Config operations
+// ---------------------------------------------------------------------------
+
+fn bench_config_operations(c: &mut Criterion) {
+    let mut group = c.benchmark_group("config_operations");
+
+    group.bench_function("default_config", |b| {
+        b.iter(|| black_box(AppConfig::default()))
+    });
+
+    group.bench_function("apply_patch_single_field", |b| {
+        let patch = ConfigPatch {
+            max_concurrent_downloads: Some(8),
+            ..Default::default()
+        };
+        b.iter(|| {
+            let mut config = AppConfig::default();
+            apply_patch(&mut config, black_box(&patch));
+            black_box(&config);
+        })
+    });
+
+    group.bench_function("apply_patch_many_fields", |b| {
+        let patch = ConfigPatch {
+            max_concurrent_downloads: Some(8),
+            max_segments_per_download: Some(16),
+            speed_limit_bytes_per_sec: Some(Some(10_485_760)),
+            max_retries: Some(10),
+            theme: Some("dark".to_string()),
+            locale: Some("fr".to_string()),
+            dynamic_split_enabled: Some(true),
+            verify_checksums: Some(true),
+            link_check_parallelism: Some(16),
+            link_check_timeout_secs: Some(30),
+            ..Default::default()
+        };
+        b.iter(|| {
+            let mut config = AppConfig::default();
+            apply_patch(&mut config, black_box(&patch));
+            black_box(&config);
+        })
+    });
+
+    group.bench_function("normalize_max_concurrent", |b| {
+        b.iter(|| black_box(normalize_max_concurrent(black_box(10))))
+    });
+
+    group.bench_function("normalize_link_check_parallelism", |b| {
+        b.iter(|| black_box(normalize_link_check_parallelism(black_box(32))))
+    });
+
+    group.finish();
+}
+
+// ---------------------------------------------------------------------------
+// Priority
+// ---------------------------------------------------------------------------
+
+fn bench_priority(c: &mut Criterion) {
+    let mut group = c.benchmark_group("priority");
+
+    group.bench_function("create_valid", |b| {
+        b.iter(|| black_box(Priority::new(black_box(5))))
+    });
+
+    group.bench_function("create_invalid", |b| {
+        b.iter(|| black_box(Priority::new(black_box(0))))
+    });
+
+    group.finish();
+}
+
+criterion_group!(
+    benches,
+    bench_url_parsing,
+    bench_download_state_machine,
+    bench_segment_operations,
+    bench_checksum_detection,
+    bench_link_status,
+    bench_config_operations,
+    bench_priority,
+);
+criterion_main!(benches);