Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel) #17779

Open
Open
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)#17779
Assignees
s1gr1d
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked

Description

@RudolfSchreier
RudolfSchreier
opened on Sep 25, 2025

Is there an existing issue for this?

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/bun

SDK Version

10.15.0

Framework Version

Express 5.1.0

Link to Sentry event

No response

Reproduction Example/SDK Setup

https://github.com/RudolfSchreier/sentry-express-bun-demo

Steps to Reproduce

  1. Get a working SENTRY_DSN for some project
  2. start the demo using env SENTRY_DSN=... bun run dev

Expected Result

The express server starts up with working Sentry integration and no warnings.

Actual Result

The express server starts up, but with a Sentry warning about missing instrumentation:

[Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you --import when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.

Additional Context

When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.

It is unclear if the warning is correct or erroneous (and Express integration is actually working).

It is unclear to me from the description of #13674 if this the expected result for Express v5.

Tip: React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.

Metadata

Metadata

Assignees

Labels

BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked

Projects

Milestone

No milestone

Relationships

None yet

Development

No branches or pull requests

Issue actions

, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel) #17779
Open
Open
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)#17779
Assignees
s1gr1d
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Description
@RudolfSchreier
RudolfSchreier
opened on Sep 25, 2025
Is there an existing issue for this?
How do you use Sentry?
Sentry Saas (sentry.io)
Which SDK are you using?
@sentry/bun
SDK Version
10.15.0
Framework Version
Express 5.1.0
Link to Sentry event
No response
Reproduction Example/SDK Setup
https://github.com/RudolfSchreier/sentry-express-bun-demo
Steps to Reproduce
  1. Get a working SENTRY_DSN for some project
  2. start the demo using env SENTRY_DSN=... bun run dev
Expected Result
The express server starts up with working Sentry integration and no warnings.
Actual Result
The express server starts up, but with a Sentry warning about missing instrumentation:
[Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you --import when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.
Additional Context
When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.
It is unclear if the warning is correct or erroneous (and Express integration is actually working).
It is unclear to me from the description of #13674 if this the expected result for Express v5.
Tip: React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.
Metadata
Metadata
Assignees
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Projects
Milestone
No milestone
Relationships
None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel) #17779
Open
Open
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)#17779
Assignees
s1gr1d
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Description
@RudolfSchreier
RudolfSchreier
opened on Sep 25, 2025
Is there an existing issue for this?
How do you use Sentry?
Sentry Saas (sentry.io)
Which SDK are you using?
@sentry/bun
SDK Version
10.15.0
Framework Version
Express 5.1.0
Link to Sentry event
No response
Reproduction Example/SDK Setup
https://github.com/RudolfSchreier/sentry-express-bun-demo
Steps to Reproduce
  1. Get a working SENTRY_DSN for some project
  2. start the demo using env SENTRY_DSN=... bun run dev
Expected Result
The express server starts up with working Sentry integration and no warnings.
Actual Result
The express server starts up, but with a Sentry warning about missing instrumentation:
[Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you --import when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.
Additional Context
When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.
It is unclear if the warning is correct or erroneous (and Express integration is actually working).
It is unclear to me from the description of #13674 if this the expected result for Express v5.
Tip: React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.
Metadata
Metadata
Assignees
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Projects
Milestone
No milestone
Relationships
None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel) #17779
Open
Open
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)#17779
Assignees
s1gr1d
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Description
@RudolfSchreier
RudolfSchreier
opened on Sep 25, 2025
Is there an existing issue for this?
How do you use Sentry?
Sentry Saas (sentry.io)
Which SDK are you using?
@sentry/bun
SDK Version
10.15.0
Framework Version
Express 5.1.0
Link to Sentry event
No response
Reproduction Example/SDK Setup
https://github.com/RudolfSchreier/sentry-express-bun-demo
Steps to Reproduce
  1. Get a working SENTRY_DSN for some project
  2. start the demo using env SENTRY_DSN=... bun run dev
Expected Result
The express server starts up with working Sentry integration and no warnings.
Actual Result
The express server starts up, but with a Sentry warning about missing instrumentation:
[Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you --import when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.
Additional Context
When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.
It is unclear if the warning is correct or erroneous (and Express integration is actually working).
It is unclear to me from the description of #13674 if this the expected result for Express v5.
Tip: React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.
Metadata
Metadata
Assignees
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Projects
Milestone
No milestone
Relationships
None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel) #17779
Open
Open
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)#17779
Assignees
s1gr1d
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Description
@RudolfSchreier
RudolfSchreier
opened on Sep 25, 2025
Is there an existing issue for this?
How do you use Sentry?
Sentry Saas (sentry.io)
Which SDK are you using?
@sentry/bun
SDK Version
10.15.0
Framework Version
Express 5.1.0
Link to Sentry event
No response
Reproduction Example/SDK Setup
https://github.com/RudolfSchreier/sentry-express-bun-demo
Steps to Reproduce
  1. Get a working SENTRY_DSN for some project
  2. start the demo using env SENTRY_DSN=... bun run dev
Expected Result
The express server starts up with working Sentry integration and no warnings.
Actual Result
The express server starts up, but with a Sentry warning about missing instrumentation:
[Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you --import when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.
Additional Context
When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.
It is unclear if the warning is correct or erroneous (and Express integration is actually working).
It is unclear to me from the description of #13674 if this the expected result for Express v5.
Tip: React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.
Metadata
Metadata
Assignees
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Projects
Milestone
No milestone
Relationships
None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel) #17779
Open
Open
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)#17779
Assignees
s1gr1d
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Description
@RudolfSchreier
RudolfSchreier
opened on Sep 25, 2025
Is there an existing issue for this?
How do you use Sentry?
Sentry Saas (sentry.io)
Which SDK are you using?
@sentry/bun
SDK Version
10.15.0
Framework Version
Express 5.1.0
Link to Sentry event
No response
Reproduction Example/SDK Setup
https://github.com/RudolfSchreier/sentry-express-bun-demo
Steps to Reproduce
  1. Get a working SENTRY_DSN for some project
  2. start the demo using env SENTRY_DSN=... bun run dev
Expected Result
The express server starts up with working Sentry integration and no warnings.
Actual Result
The express server starts up, but with a Sentry warning about missing instrumentation:
[Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you --import when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.
Additional Context
When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.
It is unclear if the warning is correct or erroneous (and Express integration is actually working).
It is unclear to me from the description of #13674 if this the expected result for Express v5.
Tip: React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.
Metadata
Metadata
Assignees
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Projects
Milestone
No milestone
Relationships
None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel) #17779
Open
Open
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)#17779
Assignees
s1gr1d
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Description
@RudolfSchreier
RudolfSchreier
opened on Sep 25, 2025
Is there an existing issue for this?
How do you use Sentry?
Sentry Saas (sentry.io)
Which SDK are you using?
@sentry/bun
SDK Version
10.15.0
Framework Version
Express 5.1.0
Link to Sentry event
No response
Reproduction Example/SDK Setup
https://github.com/RudolfSchreier/sentry-express-bun-demo
Steps to Reproduce
  1. Get a working SENTRY_DSN for some project
  2. start the demo using env SENTRY_DSN=... bun run dev
Expected Result
The express server starts up with working Sentry integration and no warnings.
Actual Result
The express server starts up, but with a Sentry warning about missing instrumentation:
[Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you --import when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.
Additional Context
When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.
It is unclear if the warning is correct or erroneous (and Express integration is actually working).
It is unclear to me from the description of #13674 if this the expected result for Express v5.
Tip: React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.
Metadata
Metadata
Assignees
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Projects
Milestone
No milestone
Relationships
None yet
Development
No branches or pull requests
Issue actions

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel) #17779
Open
Open
Using both Bun and Express leads to "express is not instrumented" warning (Bun not publishing to http Diagnostic Channel)#17779
Assignees
s1gr1d
Labels
BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
Description
@RudolfSchreier
RudolfSchreier
opened on Sep 25, 2025
Is there an existing issue for this?
How do you use Sentry?
Sentry Saas (sentry.io)
Which SDK are you using?
@sentry/bun
SDK Version
10.15.0
Framework Version
Express 5.1.0
Link to Sentry event
No response
Reproduction Example/SDK Setup
https://github.com/RudolfSchreier/sentry-express-bun-demo
Steps to Reproduce
  1. Get a working SENTRY_DSN for some project
  2. start the demo using env SENTRY_DSN=... bun run dev
Expected Result
The express server starts up with working Sentry integration and no warnings.
Actual Result
The express server starts up, but with a Sentry warning about missing instrumentation:
[Sentry] express is not instrumented. Please make sure to initialize Sentry in a separate file that you --import when running node, see: https://docs.sentry.io/platforms/javascript/guides/express/install/esm/.
Additional Context
When using both Bun and Express, it is unclear which SDK to preferably use (@sentry/node or @sentry/bun), but both appear to show this issue.
It is unclear if the warning is correct or erroneous (and Express integration is actually working).
It is unclear to me from the description of #13674 if this the expected result for Express v5.
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BugBunExternal DependencyTo close this issue, an external dependency needs to be adjusted/fixedState: Blocked
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