diff --git a/copyparty/__main__.py b/copyparty/__main__.py
index caa77a94..6a3ba91b 100644
--- a/copyparty/__main__.py
+++ b/copyparty/__main__.py
@@ -23,7 +23,7 @@ from textwrap import dedent
 from .__init__ import E, WINDOWS, VT100, PY2
 from .__version__ import S_VERSION, S_BUILD_DT, CODENAME
 from .svchub import SvcHub
-from .util import py_desc, align_tab, IMPLICATIONS
+from .util import py_desc, align_tab, IMPLICATIONS, alltrace
 
 HAVE_SSL = True
 try:
@@ -182,6 +182,16 @@ def sighandler(sig=None, frame=None):
     print("\n".join(msg))
 
 
+def stackmon(fp, ival):
+    ctr = 0
+    while True:
+        ctr += 1
+        time.sleep(ival)
+        st = "{}, {}\n{}".format(ctr, time.time(), alltrace())
+        with open(fp, "wb") as f:
+            f.write(st.encode("utf-8", "replace"))
+
+
 def run_argparse(argv, formatter):
     ap = argparse.ArgumentParser(
         formatter_class=formatter,
@@ -320,6 +330,7 @@ def run_argparse(argv, formatter):
     ap2.add_argument("--no-sendfile", action="store_true", help="disable sendfile")
     ap2.add_argument("--no-scandir", action="store_true", help="disable scandir")
     ap2.add_argument("--no-fastboot", action="store_true", help="wait for up2k indexing")
+    ap2.add_argument("--stackmon", metavar="P,S", help="write stacktrace to Path every S second")
     
     return ap.parse_args(args=argv[1:])
     # fmt: on
@@ -359,6 +370,16 @@ def main(argv=None):
     except AssertionError:
         al = run_argparse(argv, Dodge11874)
 
+    if al.stackmon:
+        fp, f = al.stackmon.rsplit(",", 1)
+        f = int(f)
+        t = threading.Thread(
+            target=stackmon,
+            args=(fp, f),
+        )
+        t.daemon = True
+        t.start()
+
     # propagate implications
     for k1, k2 in IMPLICATIONS:
         if getattr(al, k1):
diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index bb4ddaaa..abef296f 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -1434,33 +1434,8 @@ class HttpCli(object):
         if self.args.no_stack:
             raise Pebkac(403, "disabled by argv")
 
-        threads = {}
-        names = dict([(t.ident, t.name) for t in threading.enumerate()])
-        for tid, stack in sys._current_frames().items():
-            name = "{} ({:x})".format(names.get(tid), tid)
-            threads[name] = stack
-
-        rret = []
-        bret = []
-        for name, stack in sorted(threads.items()):
-            ret = ["\n\n# {}".format(name)]
-            pad = None
-            for fn, lno, name, line in traceback.extract_stack(stack):
-                fn = os.sep.join(fn.split(os.sep)[-3:])
-                ret.append('File: "{}", line {}, in {}'.format(fn, lno, name))
-                if line:
-                    ret.append("  " + str(line.strip()))
-                    if "self.not_empty.wait()" in line:
-                        pad = " " * 4
-
-            if pad:
-                bret += [ret[0]] + [pad + x for x in ret[1:]]
-            else:
-                rret += ret
-
-        ret = rret + bret
-        ret = ("<pre>" + "\n".join(ret)).encode("utf-8")
-        self.reply(ret)
+        ret = "<pre>{}\n{}".format(time.time(), alltrace())
+        self.reply(ret.encode("utf-8"))
 
     def tx_tree(self):
         top = self.uparam["tree"] or ""
diff --git a/copyparty/util.py b/copyparty/util.py
index fb71bdc9..4a2308ec 100644
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -254,6 +254,34 @@ def trace(*args, **kwargs):
     nuprint(msg)
 
 
+def alltrace():
+    threads = {}
+    names = dict([(t.ident, t.name) for t in threading.enumerate()])
+    for tid, stack in sys._current_frames().items():
+        name = "{} ({:x})".format(names.get(tid), tid)
+        threads[name] = stack
+
+    rret = []
+    bret = []
+    for name, stack in sorted(threads.items()):
+        ret = ["\n\n# {}".format(name)]
+        pad = None
+        for fn, lno, name, line in traceback.extract_stack(stack):
+            fn = os.sep.join(fn.split(os.sep)[-3:])
+            ret.append('File: "{}", line {}, in {}'.format(fn, lno, name))
+            if line:
+                ret.append("  " + str(line.strip()))
+                if "self.not_empty.wait()" in line:
+                    pad = " " * 4
+
+        if pad:
+            bret += [ret[0]] + [pad + x for x in ret[1:]]
+        else:
+            rret += ret
+
+    return "\n".join(rret + bret)
+
+
 def min_ex():
     et, ev, tb = sys.exc_info()
     tb = traceback.extract_tb(tb, 2)