Web SDK Compatibility

This document details the browsers, frameworks, build tools, and related limitations supported by Web RUM SDK, helping you evaluate SDK applicability in your target environment.

Supported Browsers

Browser	Desktop	Mobile	Min Version	Notes
Chrome	✅	✅	63+	Full feature support
Firefox	✅	-	67+	Some features limited (see below)
Safari	✅	✅	12.1+	Some features limited (see below)
Edge	✅	-	79+	Chromium-based version
Opera	✅	-	50+	Full feature support
Internet Explorer	❌	-	-	Not supported

Internet Explorer 11 and earlier versions are not supported.

Browser Feature Compatibility

The following table details SDK feature support across browsers:

Feature	Chrome	Firefox	Safari	Edge	Chrome Android	Safari iOS	Opera
SDK Loading	✅	✅	✅	✅	✅	✅	✅
SDK Initialization	✅	✅	✅	✅	✅	✅	✅
RUM Data Reporting	✅	✅	✅	✅	✅	✅	✅
Page Hidden Flush	✅	✅	✅	✅	✅	❌	✅
Console Error Capture	✅	✅	✅	✅	✅	✅	✅
Runtime Error Capture	✅	✅	✅	✅	✅	✅	✅
CSP Violation Detection	✅	✅	✅	✅	✅	✅	✅
Browser Intervention Detection	✅	❌	❌	✅	✅	❌	✅
Auto Action Tracking	✅	✅	✅	✅	✅	✅	✅
Custom Action Tracking	✅	✅	✅	✅	✅	✅	✅
Long Task Detection	✅	❌	❌	✅	✅	❌	✅
Distributed Tracing	✅	✅	✅	✅	✅	✅	✅
Route Change Tracking	✅	✅	✅	✅	✅	✅	✅
Page Load Time	✅	✅	✅	✅	✅	✅	✅
Resource Performance	✅	✅	⚠️ (1)	✅	✅	⚠️ (1)	✅
Navigation Performance	✅	✅	✅	✅	✅	✅	✅
Web Vitals	✅	⚠️ (2)	⚠️ (2)	✅	✅	⚠️ (2)	✅
FCP (First Contentful Paint)	✅	✅	✅	✅	✅	✅	✅

Notes:

Resource size information unavailable
Only FID (First Input Delay) metric supported

Framework Compatibility

JavaScript Frameworks

React

Supports React 16.8+ (Hooks), auto tracking ✅

Vue.js

Supports Vue 2.x and Vue 3.x, auto tracking ✅

Angular

Supports Angular 12+, auto tracking ✅

Next.js

Supports SSR and client-side rendering, auto tracking ✅

Nuxt.js

Supports SSR and client-side rendering, auto tracking ✅

Svelte

Requires additional configuration for auto tracking ⚠️

Vanilla JavaScript fully supports manual tracking features.

Build Tools

Tool	Support Status	Notes
Webpack	✅	Supports all major versions (4.x, 5.x)
Vite	✅	Recommended
Rollup	✅	Full support
Parcel	✅	Full support
esbuild	✅	Full support
Turbopack	✅	Experimental support

Module Systems

Module System	Support Status	Notes
ES Module (ESM)	✅	Recommended
CommonJS (CJS)	✅	Full support
UMD	✅	Suitable for direct browser import

Network Request Library Compatibility

Library/API	Auto Tracking	Manual Tracking	Notes
Fetch API	✅	✅	Requires auto tracking configuration enabled
XMLHttpRequest	✅	✅	Requires auto tracking configuration enabled
Axios	✅	✅	Auto tracking via interceptors
jQuery.ajax	⚠️	✅	Based on XMLHttpRequest, requires configuration

Web API Dependencies

The SDK depends on the following Web APIs. Please ensure target browsers support them:

Required APIs

API	Purpose	Fallback
`navigator.sendBeacon`	Send data on page unload	Uses Fetch API
`fetch`	Data reporting	None
`Promise`	Async handling	None
`JSON`	Data serialization	None

Optional APIs

API	Purpose	Impact When Missing
`PerformanceObserver`	Performance monitoring	Some performance metrics unavailable
`PerformanceNavigationTiming`	Navigation performance data	Cannot get navigation performance metrics
`PerformanceResourceTiming`	Resource loading performance data	Cannot get resource performance metrics
`IntersectionObserver`	Element visibility detection	Some user behavior tracking affected
`MutationObserver`	DOM change monitoring	Some auto tracking features affected
`PerformanceLongTaskTiming`	Long task detection	Cannot detect long tasks
`visibilitychange` event	Page visibility change detection	Some session tracking features affected

TypeScript Support

TypeScript Version	Support Status	Notes
4.0+	✅	Complete type definitions provided
3.8 - 3.9	⚠️	Basic support, some types limited
< 3.8	❌	Not supported

The SDK provides complete TypeScript type definition files (.d.ts), supporting IntelliSense and type checking.

Content Security Policy (CSP)

If your website uses CSP, add the following to your CSP policy:

CSP Configuration

Content-Security-Policy:
  connect-src 'self' https://rum-intake.flashcat.cloud;
  script-src 'self' 'unsafe-inline';

If using CDN integration, also add https://static.flashcat.cloud to script-src.

Privacy and Security

The SDK may use the following storage types:

Storage Type	Purpose	Required
localStorage	Session state persistence	Optional
sessionStorage	Temporary session data	Optional
Cookie	User identification (configurable)	Optional

Cookies and local storage can be disabled via configuration to use pure memory mode. The SDK uses SameSite=Lax policy by default, compatible with modern browser privacy requirements.

Known Limitations

Safari Limitations

Limitation	Description
Long Task Detection	Safari doesn’t support Long Tasks API
Web Vitals	Only FID supported, CLS and LCP full measurement not supported
Resource Size Information	Some resource size information may be inaccurate
Data Send on Page Hidden	iOS Safari cannot guarantee immediate data send when page is hidden

Firefox Limitations

Limitation	Description
Long Task Detection	Firefox doesn’t support Long Tasks API
Browser Intervention Detection	Firefox doesn’t support Intervention API
Web Vitals	Only FID supported

Mobile Browser Limitations

Background Running Restrictions - Mobile browsers may pause JavaScript execution when in background
Memory Limitations - Mobile device memory constraints may affect data caching capability
Network Limitations - Unstable mobile networks may cause data reporting delays

Single Page Applications (SPA)

Route change tracking configuration needs to be enabled
Some framework routing libraries require additional configuration
Recommend manually calling startView method to track route changes

See Advanced Configuration for detailed SPA route tracking configuration.

Performance Impact

FlashCat Web SDK is designed to be lightweight with minimal impact on webpage performance:

SDK Size: ~30 KB (~10 KB gzipped)
Runtime Memory Usage: < 2 MB
CPU Usage: < 1%
First Load Impact: < 50ms

Update Strategy

Major Version Updates: May contain breaking changes, code adjustments required
Minor Version Updates: New features, backward compatible
Patch Version Updates: Bug fixes, fully backward compatible

We recommend regularly updating the SDK to the latest stable version for best performance and security.

Minimum Deployment Requirements

To ensure the SDK works properly, please ensure:

Browser Versions:
- Chrome 63+
- Firefox 67+
- Safari 12.1+
- Edge 79+
JavaScript Support: ES6+ (ES2015)
Required Web APIs:
- fetch API
- Promise
- JSON
Network Access: Application needs to access https://rum-intake.flashcat.cloud for data reporting
HTTPS: Recommended to use in HTTPS environment for full feature support

SDK Integration Guide

Learn how to integrate the SDK

Advanced Configuration

Learn about advanced SDK configuration options

Data Collection

Learn what data the SDK collects

Quick Start

Analytics

SDK Integration

Performance

Error Tracking

Explorer

Session Replay

Best Practices

Others

Supported Browsers

Browser Feature Compatibility

Framework Compatibility

JavaScript Frameworks

React

Vue.js

Angular

Next.js

Nuxt.js

Svelte

Build Tools

Module Systems

Network Request Library Compatibility

Web API Dependencies

Required APIs

Optional APIs

TypeScript Support

Content Security Policy (CSP)

Privacy and Security

Known Limitations

Performance Impact

Update Strategy

Minimum Deployment Requirements

SDK Integration Guide

Advanced Configuration

Data Collection

​Supported Browsers

​Browser Feature Compatibility

​Framework Compatibility

​JavaScript Frameworks

React

Vue.js

Angular

Next.js

Nuxt.js

Svelte

​Build Tools

​Module Systems

​Network Request Library Compatibility

​Web API Dependencies

​Required APIs

​Optional APIs

​TypeScript Support

​Content Security Policy (CSP)

​Privacy and Security

​Cookie Usage

​SameSite Cookie

​Known Limitations

​Performance Impact

​Update Strategy

​Minimum Deployment Requirements

​Related Documentation

SDK Integration Guide

Advanced Configuration

Data Collection

Supported Browsers

Browser Feature Compatibility

Framework Compatibility

JavaScript Frameworks

Build Tools

Module Systems

Network Request Library Compatibility

Web API Dependencies

Required APIs

Optional APIs

TypeScript Support

Content Security Policy (CSP)

Privacy and Security

Cookie Usage

SameSite Cookie

Known Limitations

Performance Impact

Update Strategy

Minimum Deployment Requirements

Related Documentation