diff --git a/docs/index.html b/docs/index.html
index 8dd89eb..f33c676 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -20,13 +20,21 @@
       <li><span id="code-validation" class="editor-validation">Valid</span></li>
     </ul>
     <pre id="code-editor" class="editor-area">{{source}}</pre>
+    <div id="code-info" class="editor-info"></div>
+  </div>
+  <div class="editor-container">
+    <ul class="editor-header">
+      <li><span>Output</span></li>
+      <li><span></span></li>
+    </ul>
     <div class="editor-sub-header">AST</div>
     <pre id="code-ast" class="editor-area"></pre>
     <div class="editor-sub-header">Optimized AST&nbsp;&nbsp;&nbsp;&nbsp;
       mode:&nbsp;<select id="opt_mode" type="checkbox"><option value="all">All</option><option value="only">Only</option></select>
     </div>
     <pre id="code-ast-optimized" class="editor-area"></pre>
-    <div id="code-info" class="editor-info"></div>
+    <div class="editor-sub-header">Profile</div>
+    <div id="profile" class="editor-area"></div>
   </div>
 </div>
 <script src="https://cdnjs.cloudflare.com/ajax/libs/ace/1.4.2/ace.js"></script>
diff --git a/docs/index.js b/docs/index.js
index 0efddd8..e4eba47 100644
--- a/docs/index.js
+++ b/docs/index.js
@@ -1,34 +1,34 @@
 // Setup editros
-const grammar = ace.edit("grammar-editor");
-grammar.setShowPrintMargin(false);
-grammar.setValue(localStorage.getItem('grammarText') || '');
-grammar.moveCursorTo(0, 0);
+function setupInfoArea(id) {
+  const e = ace.edit(id);
+  e.setShowPrintMargin(false);
+  e.setOptions({
+    readOnly: true,
+    highlightActiveLine: false,
+    highlightGutterLine: false
+  })
+  e.renderer.$cursorLayer.element.style.opacity=0;
+  return e;
+}
 
-const code = ace.edit("code-editor");
-code.setShowPrintMargin(false);
-code.setValue(localStorage.getItem('codeText') || '');
-code.moveCursorTo(0, 0);
+function setupEditorArea(id, lsKey) {
+  const e = ace.edit(id);
+  e.setShowPrintMargin(false);
+  e.setValue(localStorage.getItem(lsKey) || '');
+  e.moveCursorTo(0, 0);
+  return e;
+}
 
-const codeAst = ace.edit("code-ast");
-codeAst.setShowPrintMargin(false);
-codeAst.setOptions({
-  readOnly: true,
-  highlightActiveLine: false,
-  highlightGutterLine: false
-})
-codeAst.renderer.$cursorLayer.element.style.opacity=0;
+const grammar = setupEditorArea("grammar-editor", "grammarText");
+const code = setupEditorArea("code-editor", "codeText");
 
-const codeAstOptimized = ace.edit("code-ast-optimized");
-codeAstOptimized.setShowPrintMargin(false);
-codeAstOptimized.setOptions({
-  readOnly: true,
-  highlightActiveLine: false,
-  highlightGutterLine: false
-})
-codeAstOptimized.renderer.$cursorLayer.element.style.opacity=0;
+const codeAst = setupInfoArea("code-ast");
+const codeAstOptimized = setupInfoArea("code-ast-optimized");
+const profile = setupInfoArea("profile");
 
 $('#opt_mode').val(localStorage.getItem('optimazationMode') || 'all');
 
+// Parse
 function escapeHtml(unsafe) {
   return unsafe
     .replace(/&/g, "&amp;")
@@ -71,6 +71,7 @@ function parse() {
   $codeValidation.hide();
   codeAst.setValue('');
   codeAstOptimized.setValue('');
+  profile.setValue('');
 
   if (grammarText.length === 0) {
    return;
@@ -84,6 +85,7 @@ function parse() {
 
     codeAst.insert(data.ast);
     codeAstOptimized.insert(data.astOptimized);
+    profile.insert(data.profile);
 
     if (data.source_valid) {
       $codeValidation.removeClass('editor-validation-invalid').text('Valid').show();
diff --git a/docs/native.cpp b/docs/native.cpp
index 8f56a21..04d4f1b 100644
--- a/docs/native.cpp
+++ b/docs/native.cpp
@@ -59,14 +59,21 @@ std::string lint(const std::string &grammarText, const std::string &codeText, bo
   std::string codeResult;
   std::string astResult;
   std::string astResultOptimized;
+  std::string profileResult;
 
   peg::parser peg;
   auto is_grammar_valid = parse_grammar(grammarText, peg, grammarResult);
   auto is_source_valid = false;
 
   if (is_grammar_valid && peg) {
+    std::stringstream ss;
+    peg::enable_profiling(peg, ss);
+
     std::shared_ptr<peg::Ast> ast;
     is_source_valid = parse_code(codeText, peg, codeResult, ast);
+
+    profileResult = escape_json(ss.str());
+
     if (ast) {
       astResult = escape_json(peg::ast_to_s(ast));
       astResultOptimized = escape_json(
@@ -83,6 +90,7 @@ std::string lint(const std::string &grammarText, const std::string &codeText, bo
     json += ",\"code\":" + codeResult;
     json += ",\"ast\":\"" + astResult + "\"";
     json += ",\"astOptimized\":\"" + astResultOptimized + "\"";
+    json += ",\"profile\":\"" + profileResult + "\"";
   }
   json += "}";
 
diff --git a/docs/native.wasm b/docs/native.wasm
index 03951e2..b85a586 100755
Binary files a/docs/native.wasm and b/docs/native.wasm differ
diff --git a/lint/peglint.cc b/lint/peglint.cc
index 724458a..c78b9b2 100644
--- a/lint/peglint.cc
+++ b/lint/peglint.cc
@@ -130,11 +130,11 @@ int main(int argc, const char **argv) {
   if (opt_packrat) { parser.enable_packrat_parsing(); }
 
   if (opt_trace) {
-    enable_tracing(parser);
+    enable_tracing(parser, std::cout);
   }
 
   if (opt_profile) {
-    enable_profiling(parser);
+    enable_profiling(parser, std::cout);
   }
 
   parser.set_verbose_trace(opt_verbose);
diff --git a/peglib.h b/peglib.h
index d7895b0..facd906 100644
--- a/peglib.h
+++ b/peglib.h
@@ -4393,7 +4393,8 @@ public:
   }
 
   void enable_trace(TracerEnter tracer_enter, TracerLeave tracer_leave,
-                    TracerStartOrEnd tracer_start, TracerStartOrEnd tracer_end) {
+                    TracerStartOrEnd tracer_start,
+                    TracerStartOrEnd tracer_end) {
     if (grammar_ != nullptr) {
       auto &rule = (*grammar_)[start_];
       rule.tracer_enter = tracer_enter;
@@ -4450,7 +4451,7 @@ private:
  *  enable_tracing
  *---------------------------------------------------------------------------*/
 
-inline void enable_tracing(parser &parser) {
+inline void enable_tracing(parser &parser, std::ostream &os) {
   size_t prev_pos = 0;
   parser.enable_trace(
       [&](auto &ope, auto s, auto, auto &, auto &c, auto &, auto &) {
@@ -4468,8 +4469,8 @@ inline void enable_tracing(parser &parser) {
           auto lit = dynamic_cast<const peg::LiteralString *>(&ope);
           if (lit) { name += " '" + peg::escape_characters(lit->lit_) + "'"; }
         }
-        std::cout << "E " << pos << backtrack << "\t" << indent << "┌" << name
-                  << " #" << c.trace_ids.back() << std::endl;
+        os << "E " << pos << backtrack << "\t" << indent << "┌" << name << " #"
+           << c.trace_ids.back() << std::endl;
         prev_pos = static_cast<size_t>(pos);
       },
       [&](auto &ope, auto s, auto, auto &sv, auto &c, auto &, auto len,
@@ -4498,9 +4499,9 @@ inline void enable_tracing(parser &parser) {
             peg::TokenChecker::is_token(const_cast<peg::Ope &>(ope))) {
           matched = ", match '" + peg::escape_characters(s, len) + "'";
         }
-        std::cout << "L " << pos << "\t" << indent << ret << name << " #"
-                  << c.trace_ids.back() << choice.str() << token << matched
-                  << std::endl;
+        os << "L " << pos << "\t" << indent << ret << name << " #"
+           << c.trace_ids.back() << choice.str() << token << matched
+           << std::endl;
       },
       [&](auto &) {}, [&](auto &) {});
 }
@@ -4509,7 +4510,7 @@ inline void enable_tracing(parser &parser) {
  *  enable_profiling
  *---------------------------------------------------------------------------*/
 
-inline void enable_profiling(parser &parser) {
+inline void enable_profiling(parser &parser, std::ostream &os) {
   struct Stats {
     struct Item {
       std::string name;
@@ -4522,8 +4523,7 @@ inline void enable_profiling(parser &parser) {
   };
 
   parser.enable_trace(
-      [&](auto &ope, auto, auto, auto &, auto &, auto &,
-          std::any &trace_data) {
+      [&](auto &ope, auto, auto, auto &, auto &, auto &, std::any &trace_data) {
         if (auto holder = dynamic_cast<const peg::Holder *>(&ope)) {
           auto &stats = *std::any_cast<Stats *>(trace_data);
 
@@ -4550,9 +4550,9 @@ inline void enable_profiling(parser &parser) {
           }
           if (index == 0) {
             size_t id = 0;
-            std::cout << "  id       total      %     success        fail  "
-                         "definition"
-                      << std::endl;
+            os << "  id       total      %     success        fail  "
+                  "definition"
+               << std::endl;
             size_t total_total, total_success = 0, total_fail = 0;
             char buff[BUFSIZ];
             for (auto &[name, success, fail] : stats.items) {
@@ -4562,18 +4562,18 @@ inline void enable_profiling(parser &parser) {
               auto ratio = total * 100.0 / stats.total;
               sprintf(buff, "%4zu  %10lu  %5.2f  %10lu  %10lu  %s", id, total,
                       ratio, success, fail, name.c_str());
-              std::cout << buff << std::endl;
+              os << buff << std::endl;
               id++;
             }
-            std::cout << std::endl;
+            os << std::endl;
             total_total = total_success + total_fail;
             sprintf(buff, "%4s  %10lu  %5s  %10lu  %10lu  %s", "", total_total,
                     "", total_success, total_fail, "Total counters");
-            std::cout << buff << std::endl;
+            os << buff << std::endl;
             sprintf(buff, "%4s  %10s  %5s  %10.2f  %10.2f  %s", "", "", "",
                     total_success * 100.0 / total_total,
                     total_fail * 100.0 / total_total, "% success/fail");
-            std::cout << buff << std::endl;
+            os << buff << std::endl;
           }
         }
       },