For transactional email
Consider SMTP2GO for website-generated messages, form notifications, account notices, and other outbound system email.
Explore SMTP2GOAvailableFree browser-local analysis
JavaScript Payload Analyzer
SiteTend JavaScript Payload
Estimate measurable JavaScript weight and find blocking, duplicate, third-party, legacy, and main-thread risk indicators.
Your input stays private.Markup and build output are analyzed in your browser.
Paste JavaScript resource information
Add HTML, script elements, resource lists, or build output with sizes.
Review payload risks
Start with blocking scripts, large payloads, and long-task risk.
Your analysis will appear here
Paste resource information and select Analyze JavaScript.
How to improve
Reduce code before rearranging bundles
Remove unused features, delay non-essential work, control third parties, and profile execution on representative mobile hardware. Treat request count and bundle structure as means to a measured user-experience outcome.
Questions
JavaScript Payload Analyzer FAQ
How does the analyzer estimate JavaScript payload?
It totals inline code and sizes explicitly included in pasted build output or markup. Resources without a stated size remain unmeasured.
Which script loading mode should I use?
Use defer for ordered scripts, async for independent scripts, and module scripts for modern module loading. Verify dependencies whenever execution timing changes.
Can a filename prove that framework code is unused?
No. Framework, runtime, and polyfill findings are investigation prompts. Confirm them with bundle composition and code-coverage tools.
Does SiteTend fetch JavaScript resources?
No. Version 1 analyzes only the content pasted into your browser.
Apply the result
From finding to verified fix
Interpret the finding
Use size and loading warnings to choose what to profile first; they do not prove that a script is unused or slow at runtime.
Common causes to inspect
- Duplicate libraries
- Large application bundles on simple pages
- Third-party scripts loaded before user intent
Practical next steps
- Inventory first- and third-party scripts
- Profile execution and coverage
- Remove, split, or defer one verified cost at a time
What this check cannot prove
Markup estimates cannot download bundles, inspect source maps, measure execution, or observe long tasks.
Recommended resources
Useful next steps for operating a website
For measuring business inquiries
Use WhatConverts to measure which marketing sources produce calls, forms, and leads. It measures outcomes; it does not fix technical website issues.
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Consider Optery if exposed personal information or data-broker listings are a concern. It is a separate privacy resource, not an SEO or website-security scanner.
Explore OpterySiteTend may earn a commission if you purchase through these links, at no additional cost to you. These services are optional and separate from SiteTend's free checks.