diff --git a/changelog.md b/changelog.md
index a3c8486..6c89002 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 2026-02-26 - 5.3.0 - feat(mailer-bin)
+use mimalloc as the global allocator for mailer-bin
+
+- Add mimalloc dependency to workspace Cargo.toml
+- Enable workspace mimalloc in rust/crates/mailer-bin/Cargo.toml
+- Register mimalloc as the #[global_allocator] in mailer-bin/src/main.rs
+- Update Cargo.lock with new mimalloc and libmimalloc-sys entries
+
 ## 2026-02-26 - 5.2.6 - fix(postinstall)
 remove legacy postinstall binary installer and packaging entry
 
diff --git a/rust/Cargo.lock b/rust/Cargo.lock
index f5eb88f..22bff7f 100644
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -894,6 +894,16 @@ version = "0.2.181"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "459427e2af2b9c839b132acb702a1c654d95e10f8c326bfc2ad11310e458b1c5"
 
+[[package]]
+name = "libmimalloc-sys"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "667f4fec20f29dfc6bc7357c582d91796c169ad7e2fce709468aefeb2c099870"
+dependencies = [
+ "cc",
+ "libc",
+]
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.11.0"
@@ -982,6 +992,7 @@ dependencies = [
  "mailer-core",
  "mailer-security",
  "mailer-smtp",
+ "mimalloc",
  "rustls",
  "serde",
  "serde_json",
@@ -1063,6 +1074,15 @@ version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
 
+[[package]]
+name = "mimalloc"
+version = "0.1.48"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1ee66a4b64c74f4ef288bcbb9192ad9c3feaad75193129ac8509af543894fd8"
+dependencies = [
+ "libmimalloc-sys",
+]
+
 [[package]]
 name = "miniz_oxide"
 version = "0.8.9"
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 7734015..3fdebe8 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -32,3 +32,4 @@ clap = { version = "4", features = ["derive"] }
 sha2 = "0.10"
 hmac = "0.12"
 pbkdf2 = { version = "0.12", default-features = false }
+mimalloc = "0.1"
diff --git a/rust/crates/mailer-bin/Cargo.toml b/rust/crates/mailer-bin/Cargo.toml
index 1730684..6dd74cd 100644
--- a/rust/crates/mailer-bin/Cargo.toml
+++ b/rust/crates/mailer-bin/Cargo.toml
@@ -22,3 +22,4 @@ dashmap.workspace = true
 base64.workspace = true
 uuid.workspace = true
 rustls = { version = "0.23", default-features = false, features = ["ring", "std"] }
+mimalloc = { workspace = true }
diff --git a/rust/crates/mailer-bin/src/main.rs b/rust/crates/mailer-bin/src/main.rs
index 5d1ad70..2008605 100644
--- a/rust/crates/mailer-bin/src/main.rs
+++ b/rust/crates/mailer-bin/src/main.rs
@@ -5,6 +5,9 @@
 //! 2. **Management mode** (`--management`) — JSON-over-stdin/stdout IPC for
 //!    integration with `@push.rocks/smartrust` from TypeScript
 
+#[global_allocator]
+static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
+
 use clap::{Parser, Subcommand};
 use dashmap::DashMap;
 use serde::{Deserialize, Serialize};
diff --git a/ts/00_commitinfo_data.ts b/ts/00_commitinfo_data.ts
index a1474fc..19ff7aa 100644
--- a/ts/00_commitinfo_data.ts
+++ b/ts/00_commitinfo_data.ts
@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartmta',
-  version: '5.2.6',
+  version: '5.3.0',
   description: 'A high-performance, enterprise-grade Mail Transfer Agent (MTA) built from scratch in TypeScript with Rust acceleration.'
 }