diff --git a/tinygrad/viz/js/index.js b/tinygrad/viz/js/index.js
index 74f3e1d5e5..5209fd6c2e 100644
--- a/tinygrad/viz/js/index.js
+++ b/tinygrad/viz/js/index.js
@@ -208,7 +208,7 @@ async function renderProfiler(path, unit) {
   // support non realtime x axis units
   const formatTime = unit === "realtime" ? formatMicroseconds : (s) => `${s} ${unit}`;
   const profiler = d3.select("#profiler").html("");
-  const buf = await (await fetch(path)).arrayBuffer();
+  const buf = cache[path] ?? await fetchValue(path);
   const view = new DataView(buf);
   let offset = 0;
   const u8 = () => { const ret = view.getUint8(offset); offset += 1; return ret; }
@@ -593,6 +593,11 @@ hljs.registerLanguage("cpp", (hljs) => ({
   contains: [{ begin: '\\b(?:float|half)[0-9]+\\b', className: 'type' }, ...hljs.getLanguage('cpp').contains]
 }));
 
+async function fetchValue(path) {
+  const res = await fetch(path);
+  return (await (res.headers.get("content-type") === "application/json" ? res.json() : res.arrayBuffer()));
+}
+
 var ret = [];
 var cache = {};
 var ctxs = null;
@@ -650,7 +655,7 @@ async function main() {
   // ** left sidebar context list
   if (ctxs == null) {
     ctxs = [{ name:"Profiler", steps:[] }];
-    for (const r of (await (await fetch("/ctxs")).json())) ctxs.push(r);
+    for (const r of await fetchValue("/ctxs")) ctxs.push(r);
     const ctxList = document.querySelector(".ctx-list");
     for (const [i,{name, steps}] of ctxs.entries()) {
       const ul = ctxList.appendChild(document.createElement("ul"));
@@ -703,8 +708,8 @@ async function main() {
   }
   // ** Disassembly view
   if (ckey.startsWith("/render")) {
-    if (step.fmt === "timeline") return renderProfiler(ckey, "clk"); // cycles on the x axis
-    if (!(ckey in cache)) cache[ckey] = ret = await (await fetch(ckey)).json();
+    if (!(ckey in cache)) cache[ckey] = ret = await fetchValue(ckey);
+    if (ret instanceof ArrayBuffer) return renderProfiler(ckey, "clk"); // cycles on the x axis
     displaySelection("#custom");
     metadata.innerHTML = "";
     const root = d3.create("div").classed("raw-text", true).node();
diff --git a/tinygrad/viz/serve.py b/tinygrad/viz/serve.py
index ed1aed51f2..cdf31c395f 100755
--- a/tinygrad/viz/serve.py
+++ b/tinygrad/viz/serve.py
@@ -219,8 +219,7 @@ def load_sqtt(profile:list[ProfileEvent]) -> None:
   for name,waves in rctx.inst_execs.items():
     events:list[ProfileEvent] = []
     prg = trace.keys[r].ret if (r:=ref_map.get(name)) else None
-    steps.append(first:={"name":prg.name if prg is not None else name, "query":f"/render?ctx={len(ctxs)}&step={len(steps)}&fmt=counters",
-                         "depth":0, "fmt":"timeline"})
+    steps.append(first:={"name":prg.name if prg is not None else name, "query":f"/render?ctx={len(ctxs)}&step={len(steps)}&fmt=counters", "depth":0})
 
     # Idle:     The total time gap between the completion of previous instruction and the beginning of the current instruction.
     #           The idle time can be caused by: