What frontend monitoring should actually give you
Most "frontend monitoring" products today are aggregated error tracking — you get a count, a stack trace, and a guess at frequency. The hard part is what they leave out: what was the user actually doing when the error fired? Relyv merges traditional RUM (real-user monitoring) with full session replay so every alert is one click away from the exact session that triggered it.
- Real-user Web Vitals (LCP, FID, INP, CLS, TTFB) from production traffic.
- Full console capture — log, info, warn, error, debug — with stack traces.
- Network capture across fetch, XMLHttpRequest, WebSocket, Server-Sent Events, and sendBeacon.
- Every error pinned to a replayable session: open dev tools <em>inside</em> the recording.
- AI-summarised root cause and pre-filled bug ticket in your tracker of choice.
Real-user monitoring without the per-event tax
Per-event pricing punishes the noisy errors that matter most. Relyv prices on sessions: 1,000/mo free, then linear tiers (Starter $24/mo annual, Pro $82/mo annual, Business $332/mo annual). Every console error, every failed network call, every Web Vital sample inside a session is included — no overage on top.
Five-protocol network capture
Other RUM tools capture fetch + XHR and stop. Relyv adds WebSocket frames, Server-Sent Events streams, and sendBeacon calls — the three transports modern frontends use for real-time data, analytics pings, and unload-time event flushing that traditional monitoring misses. You see the WebSocket frame the chat app dropped, the SSE stream that disconnected mid-update, and the beacon that never fired before the user closed the tab.
Privacy + perf — engineered for production traffic
PII is masked on-device before any data leaves the browser. The SDK adds under 30KB gzipped and runs sub-1% CPU overhead on the main thread. Async load by default; no impact on Time to Interactive. GDPR-compatible; full DPA available; SOC 2 Type II in progress.
How it compares to the APM giants
Traditional APM/RUM products focus on aggregate dashboards and quotas-per-event. Relyv focuses on the single-session debugging loop: every error → a replay → a draft ticket → a runnable test → a live patch. Both shapes have a place; if you already run a full APM for backend trace correlation, Relyv slots in on the frontend side without conflict.