What is CrashSense?

CrashSense is an intelligent crash diagnosis SDK for JavaScript, React, and Vue applications. It goes beyond traditional error monitoring by capturing system state alongside errors — memory pressure, event loop saturation, network conditions, and framework-specific context — to tell you why your app crashed, not just what threw an exception.

The Problem

Traditional error monitoring shows you this:

TypeError: Cannot read properties of undefined (reading 'map')
    at UserList (UserList.tsx:42)
    at renderWithHooks (react-dom.development.js:14985)
    at mountIndeterminateComponent (react-dom.development.js:17811)

Now what? Is it a race condition? A failed API call? A memory leak? A hydration mismatch? You have no idea. Enjoy your next 3 hours of debugging.

The Solution

With CrashSense, the same crash gives you this:

{
  category: "memory_issue",
  subcategory: "memory_leak",
  confidence: 0.87,
  severity: "critical",

  contributingFactors: [
    { factor: "high_memory_utilization", weight: 0.9, evidence: "Heap at 92% (487MB / 528MB)" },
    { factor: "memory_growing_trend",   weight: 0.8, evidence: "Heap growing at 2.3MB/s over 60s" },
    { factor: "high_long_task_count",   weight: 0.6, evidence: "4 long tasks in last 30s (avg 340ms)" },
  ],

  system: {
    memory: { trend: "growing", utilizationPercent: 92.2 },
    cpu: { longTasksLast30s: 4, estimatedBlockingTime: 1360 },
    network: { failedRequestsLast60s: 0, isOnline: true },
  },

  breadcrumbs: [
    { type: "navigation", message: "User navigated to /checkout" },
    { type: "click",      message: "User clicked 'Add to Cart'" },
    { type: "network",    message: "POST /api/cart → 200 (142ms)" },
    { type: "console",    message: "Warning: memory pressure elevated" },
  ],

  // With @crashsense/ai:
  aiAnalysis: {
    rootCause: "Memory leak in useEffect — event listener not cleaned up",
    fix: { code: "return () => window.removeEventListener('resize', handler);" },
    prevention: "Always return cleanup functions from useEffect with side effects",
  }
}

Root cause identified. Fix suggested. Time saved: 3 hours.

Key Features

Crash Classification with Confidence Scoring

Every crash is classified into one of 7 categories with a confidence score (0.0–1.0) and a list of contributing factors with evidence strings.

AI-Powered Fix Suggestions

Bring your own LLM (OpenAI, Anthropic, Google, or any OpenAI-compatible endpoint). CrashSense sends a structured, token-optimized crash payload to your AI and returns a parsed root cause analysis with fix code.

Pre-Crash Warning System

3-tier escalating alerts detect dangerous system conditions before the browser tab crashes: elevated, critical, and imminent warnings based on memory pressure and iframe count.

Plugin System

Intercept, enrich, or drop crash events with custom plugins. Build backend reporters, filters, or custom enrichment logic.

Breadcrumb Trail

Automatic capture of clicks, navigation, network requests, console output, and state changes — the full trail leading to every crash.

Privacy-First

Emails, IPs, auth tokens, and credit card numbers are auto-scrubbed at the SDK level before any data leaves the browser.

CrashSense vs. The Rest

Capability	CrashSense	Sentry	LogRocket	Bugsnag
Root cause classification	7 categories + confidence	Stack trace only	No	Basic grouping
Memory leak detection	Trends + utilization	No	No	No
Event loop blocking	Long Task monitoring	No	No	No
React crash detection	Hydration, re-renders, hooks	ErrorBoundary only	Partial	Partial
Vue crash detection	Reactivity loops, lifecycle	Partial	Partial	Partial
Pre-crash warnings	3-tier escalation	No	No	No
AI fix suggestions	Bring your own LLM	No	No	No
PII auto-scrubbing	SDK-level	Server-side	No	Limited
Bundle size (gzipped)	~7KB	~30KB	~80KB	~15KB
Runtime dependencies	0	Multiple	Multiple	Multiple
Open source	MIT	BSL	Proprietary	Proprietary
Pricing	Free	Free tier (5K events)	$99/mo	$59/mo

Crash Categories

Category	What It Detects	How
runtime_error	TypeError, ReferenceError, RangeError, etc.	Error type analysis
memory_issue	Memory leaks, heap spikes, memory pressure	performance.memory + trend analysis
event_loop_blocking	Infinite loops, long tasks, frozen UI	Long Task API + frame timing
framework_react	Hydration mismatches, infinite re-renders, hook violations	React adapter instrumentation
framework_vue	Reactivity loops, lifecycle errors, watcher cascades	Vue adapter instrumentation
network_induced	Offline crashes, CORS blocks, timeouts, failed requests	Network monitoring + error analysis
iframe_overload	Excessive iframes exhausting memory	MutationObserver + memory correlation

Packages

Package	Description	Size
@crashsense/core	Crash detection engine — monitors, classifiers, event bus	~7KB
@crashsense/react	React ErrorBoundary + hooks + hydration detector	~1.3KB
@crashsense/vue	Vue plugin + composables + reactivity tracker	~1.2KB
@crashsense/ai	AI analysis client — any LLM endpoint	~3.1KB
@crashsense/types	Shared TypeScript types	types only
@crashsense/utils	Internal utilities	~2.5KB

Performance Budget

Metric	Budget
CPU overhead	< 2%
Memory footprint	< 5MB
Core bundle (gzipped)	< 15KB
SDK errors	Never crash the host app

All monitoring uses passive browser APIs (PerformanceObserver, MutationObserver). Zero monkey-patching by default.

Browser Support

Browser	Version
Chrome	80+
Firefox	80+
Safari	14+
Edge	80+
Node.js	18+

TIP

performance.memory is Chrome-only. Memory monitoring gracefully degrades in other browsers. All other features work cross-browser.