diff --git a/crates/perry-stdlib/src/common/dispatch.rs b/crates/perry-stdlib/src/common/dispatch.rs
index 29019e267..33c5533ed 100644
--- a/crates/perry-stdlib/src/common/dispatch.rs
+++ b/crates/perry-stdlib/src/common/dispatch.rs
@@ -296,14 +296,23 @@ pub unsafe extern "C" fn js_handle_method_dispatch(
 
     // zlib Transform streams (#1843): `zlib.createGzip()` etc. return handles
     // in the 0x60000+ range; their `.write`/`.end`/`.on`/`.pipe`/`.flush`/
-    // `.close` calls lose their static type and route here. Gated on the
-    // registry AND the method vocabulary so a handle-id reused across another
-    // subsystem's registry can't misroute (handle id-spaces aren't unified —
-    // see the long comment above).
+    // `.params`/`.reset`/`.close` calls lose their static type and route here.
+    // Gated on the registry AND the method vocabulary so a handle-id reused
+    // across another subsystem's registry can't misroute (handle id-spaces
+    // aren't unified — see the long comment above).
     #[cfg(feature = "compression")]
     if matches!(
         method_name,
-        "write" | "end" | "on" | "once" | "pipe" | "flush" | "close" | "destroy"
+        "write"
+            | "end"
+            | "on"
+            | "once"
+            | "pipe"
+            | "flush"
+            | "params"
+            | "reset"
+            | "close"
+            | "destroy"
     ) && crate::zlib::is_zlib_stream_handle(handle)
     {
         // zlib streams are synchronous, so nothing else triggers the pump
@@ -321,7 +330,17 @@ pub unsafe extern "C" fn js_handle_method_dispatch(
     #[cfg(all(feature = "external-zlib-pump", not(feature = "compression")))]
     if matches!(
         method_name,
-        "write" | "end" | "on" | "once" | "addListener" | "pipe" | "flush" | "close" | "destroy"
+        "write"
+            | "end"
+            | "on"
+            | "once"
+            | "addListener"
+            | "pipe"
+            | "flush"
+            | "params"
+            | "reset"
+            | "close"
+            | "destroy"
     ) {
         extern "C" {
             fn js_ext_zlib_is_stream_handle(handle: i64) -> i32;
@@ -793,10 +812,10 @@ unsafe fn dispatch_net_socket(handle: i64, method: &str, args: &[f64]) -> f64 {
 /// Dispatch a method call on a zlib Transform-stream handle (#1843).
 ///
 /// `createGzip()` / `createDeflate()` / `createBrotliCompress()` / … return
-/// handles whose `.write`/`.end`/`.on`/`.pipe`/`.flush`/`.close` lose their
-/// static type and arrive here. Compression is synchronous and buffered in the
-/// runtime: `.write()` accumulates input, `.end()` runs the codec and queues
-/// 'data'/'end' onto the deferred-event pump.
+/// handles whose `.write`/`.end`/`.on`/`.pipe`/`.flush`/`.params`/`.reset`/
+/// `.close` lose their static type and arrive here. Compression is synchronous
+/// and buffered in the runtime: `.write()` accumulates input, `.end()` runs the
+/// codec and queues 'data'/'end' onto the deferred-event pump.
 #[cfg(feature = "compression")]
 unsafe fn dispatch_zlib_stream(handle: i64, method: &str, args: &[f64]) -> f64 {
     fn unbox_to_i64(v: f64) -> i64 {
@@ -845,6 +864,20 @@ unsafe fn dispatch_zlib_stream(handle: i64, method: &str, args: &[f64]) -> f64 {
             crate::zlib::zlib_stream_flush(handle, cb);
             f64::from_bits(UNDEFINED)
         }
+        "params" => {
+            let cb = args
+                .iter()
+                .rev()
+                .find(|a| (a.to_bits() >> 48) == 0x7FFD)
+                .map(|a| unbox_to_i64(*a))
+                .unwrap_or(0);
+            crate::zlib::zlib_stream_params(handle, cb);
+            f64::from_bits(UNDEFINED)
+        }
+        "reset" => {
+            crate::zlib::zlib_stream_reset(handle);
+            f64::from_bits(UNDEFINED)
+        }
         _ => f64::from_bits(UNDEFINED),
     }
 }
@@ -1057,6 +1090,9 @@ pub unsafe extern "C" fn js_handle_property_dispatch(
     // bind a closure here so the typeof short-circuit sees "function".
     #[cfg(feature = "compression")]
     if crate::zlib::is_zlib_stream_handle(handle) {
+        if property_name == "bytesWritten" {
+            return crate::zlib::zlib_stream_bytes_written(handle);
+        }
         let method: Option<&'static [u8]> = match property_name {
             "write" => Some(b"write"),
             "end" => Some(b"end"),
@@ -1065,6 +1101,8 @@ pub unsafe extern "C" fn js_handle_property_dispatch(
             "emit" => Some(b"emit"),
             "pipe" => Some(b"pipe"),
             "flush" => Some(b"flush"),
+            "params" => Some(b"params"),
+            "reset" => Some(b"reset"),
             "removeListener" => Some(b"removeListener"),
             "removeAllListeners" => Some(b"removeAllListeners"),
             _ => None,
diff --git a/crates/perry-stdlib/src/zlib.rs b/crates/perry-stdlib/src/zlib.rs
index 842137de8..86f312a2d 100644
--- a/crates/perry-stdlib/src/zlib.rs
+++ b/crates/perry-stdlib/src/zlib.rs
@@ -476,6 +476,8 @@ struct ZlibStreamState {
     /// Only used by `createUnzip` (buffer-until-end auto-detect).
     input: Vec<u8>,
     ended: bool,
+    bytes_written: usize,
+    pending_bytes_written: usize,
     /// Destinations registered via `.pipe(dest)` — stored as NaN-boxed bits;
     /// 'data'/'end' are forwarded to each via dynamic method dispatch.
     pipes: Vec<u64>,
@@ -546,6 +548,8 @@ fn create_zlib_stream(codec: Codec) -> i64 {
             codec_state: make_codec_state(codec),
             input: Vec::new(),
             ended: false,
+            bytes_written: 0,
+            pending_bytes_written: 0,
             pipes: Vec::new(),
         },
     );
@@ -799,19 +803,22 @@ pub unsafe fn zlib_stream_write(handle: i64, chunk: f64) {
     let event = {
         let mut g = ZLIB_STREAMS.lock().unwrap();
         match g.get_mut(&handle) {
-            Some(s) if !s.ended => match s.codec_state.as_mut() {
-                Some(cs) => match cs.write_chunk(&bytes) {
-                    Ok(()) => {
-                        let out = cs.drain();
-                        (!out.is_empty()).then(|| ZlibEvent::Data(handle, out))
+            Some(s) if !s.ended => {
+                s.pending_bytes_written = s.pending_bytes_written.saturating_add(bytes.len());
+                match s.codec_state.as_mut() {
+                    Some(cs) => match cs.write_chunk(&bytes) {
+                        Ok(()) => {
+                            let out = cs.drain();
+                            (!out.is_empty()).then(|| ZlibEvent::Data(handle, out))
+                        }
+                        Err(e) => Some(ZlibEvent::Error(handle, e.to_string())),
+                    },
+                    None => {
+                        s.input.extend_from_slice(&bytes);
+                        None
                     }
-                    Err(e) => Some(ZlibEvent::Error(handle, e.to_string())),
-                },
-                None => {
-                    s.input.extend_from_slice(&bytes);
-                    None
                 }
-            },
+            }
             _ => return,
         }
     };
@@ -854,6 +861,46 @@ pub fn zlib_stream_flush(handle: i64, cb: i64) {
     perry_runtime::event_pump::js_notify_main_thread();
 }
 
+/// `stream.params(level, strategy, cb?)` — Perry does not currently retune
+/// compression levels, but Node exposes this as a function and invokes the
+/// callback asynchronously when parameters are unchanged.
+pub fn zlib_stream_params(_handle: i64, cb: i64) {
+    if cb != 0 {
+        ZLIB_PENDING_EVENTS
+            .lock()
+            .unwrap()
+            .push(ZlibEvent::Callback(cb));
+        perry_runtime::event_pump::js_notify_main_thread();
+    }
+}
+
+/// `stream.reset()` — reset buffered codec state and byte accounting.
+pub fn zlib_stream_reset(handle: i64) {
+    let mut g = ZLIB_STREAMS.lock().unwrap();
+    if let Some(s) = g.get_mut(&handle) {
+        s.codec_state = make_codec_state(s.codec);
+        s.input.clear();
+        s.ended = false;
+        s.bytes_written = 0;
+        s.pending_bytes_written = 0;
+    }
+}
+
+pub fn zlib_stream_bytes_written(handle: i64) -> f64 {
+    ZLIB_STREAMS
+        .lock()
+        .unwrap()
+        .get(&handle)
+        .map(|s| s.bytes_written as f64)
+        .unwrap_or(0.0)
+}
+
+fn publish_zlib_bytes_written(handle: i64) {
+    if let Some(s) = ZLIB_STREAMS.lock().unwrap().get_mut(&handle) {
+        s.bytes_written = s.pending_bytes_written;
+    }
+}
+
 fn finish_zlib_stream(handle: i64) {
     let (codec_state, codec, input) = {
         let mut g = ZLIB_STREAMS.lock().unwrap();
@@ -1015,6 +1062,7 @@ pub unsafe extern "C" fn js_zlib_process_pending() -> i32 {
     for ev in events {
         match ev {
             ZlibEvent::Data(id, bytes) => {
+                publish_zlib_bytes_written(id);
                 let cbs = listeners_for(id, "data");
                 if !cbs.is_empty() {
                     if let Some(buf_f64) = make_buffer(&bytes) {
@@ -1032,6 +1080,7 @@ pub unsafe extern "C" fn js_zlib_process_pending() -> i32 {
                 }
             }
             ZlibEvent::End(id) => {
+                publish_zlib_bytes_written(id);
                 for cb in listeners_for(id, "end") {
                     if cb != 0 {
                         js_closure_call0(cb as *const ClosureHeader);
diff --git a/test-parity/node-suite/zlib/streams/instance-methods-and-bytes.ts b/test-parity/node-suite/zlib/streams/instance-methods-and-bytes.ts
new file mode 100644
index 000000000..a9bb08301
--- /dev/null
+++ b/test-parity/node-suite/zlib/streams/instance-methods-and-bytes.ts
@@ -0,0 +1,26 @@
+import * as zlib from "node:zlib";
+
+const gzip = zlib.createGzip();
+
+console.log("params typeof:", typeof gzip.params);
+console.log("reset typeof:", typeof gzip.reset);
+console.log("bytesWritten typeof:", typeof gzip.bytesWritten);
+console.log("bytesWritten initial:", gzip.bytesWritten);
+console.log("bytesRead typeof:", typeof (gzip as any).bytesRead);
+
+gzip.destroy();
+
+const written = zlib.createGzip();
+written.on("data", () => {});
+const finished = new Promise<void>((resolve, reject) => {
+  written.on("end", () => {
+    console.log("bytesWritten on end:", written.bytesWritten);
+    resolve();
+  });
+  written.on("error", reject);
+});
+
+written.end(Buffer.from("abc"));
+console.log("bytesWritten after end call:", written.bytesWritten);
+
+await finished;