HAR File Analyzer & Cloudflare Timing Inspector
Open and inspect network waterfalls with dedicated Cloudflare analysis: break down cfedge, cforigin, and cfworker latencies, audit cf-cache-status, inspect ray POPs, and get instant answers for frequent debugging questions.
Drop your .har file here
or click to browse — 100% client-side, zero upload to any server
HAR & Cloudflare Analysis Results
Cloudflare Routing & Timing Breakdown
Edge, Origin, and Worker latency telemetry extracted from Server-Timing and Cloudflare headers
cf-cache-status)
Click a status badge to filter the request table below
Cloudflare Timing Breakdown (Server-Timing)
Edge Data Centers & POPs (cf-ray)
Answers to Frequent Questions About This HAR File
Automated intelligence computed directly from your uploaded capture| Status | Method | URL | Cloudflare | Type | Size | Time | Timeline |
|---|
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No installs — every tool below runs directly in your browser.
Everything You Need in a Modern HAR & Cloudflare Analyzer
Built for frontend engineers, DevOps teams, SREs and performance auditors.
Cloudflare Timing Breakdown
Extracts cfedge, cforigin, and cfworker from Server-Timing headers to isolate origin processing delays from edge and worker latency.
cf-cache-status Audit
Quantifies edge caching efficiency with breakdown of HIT, MISS, DYNAMIC, BYPASS, EXPIRED, and REVALIDATED statuses plus origin bytes saved.
Automated HAR File Q&A
Answers crucial questions automatically: Was caching effective? Which requests caused the longest TTFB? Were there 520-526 Cloudflare errors?
Interactive Waterfall Chart
Visualizes DNS, connect, SSL handshake, request send, TTFB wait, and content download phases exactly as captured by devtools.
100% Client-Side Privacy
All HAR parsing executes inside your browser tab. Session cookies, authorization tokens, API keys, and captured responses never leave your computer.
Multi-Filter & One-Click Export
Filter by HTTP status code, Cloudflare cache status, MIME type, or URL regex. Export parsed summaries as JSON or Markdown tickets for your team.
How to Inspect Cloudflare Latency in a HAR File
Four easy steps to diagnose slow requests, cache misses, and worker execution times.
Export HAR File
Open browser DevTools (Network tab), check "Preserve log", recreate the scenario, and select "Save all as HAR with content".
Drop or Load Demo
Drag your .har file into the upload zone or test with our sample Cloudflare HAR to preview real-time metrics.
Inspect Cloudflare Timing
Examine cfedge vs cforigin vs cfworker bars, check cache hit ratio, and view POP routing.
Review Q&A & Export
Check automated answers for slow requests and copy the Markdown diagnostic report directly into your issue tracker.
Comprehensive Guide to Cloudflare HAR Analysis & Timing Inspection
A HAR (HTTP Archive) file records the exact sequence of HTTP requests and responses exchanged between a client and a web application. When your site is routed through Cloudflare's global anycast network, every response contains rich diagnostic headers and timing metadata. Reading this information directly from raw JSON can be challenging, but understanding headers like cf-ray, cf-cache-status, and Server-Timing values (such as cfedge, cforigin, and cfworker) is essential for pinpointing performance bottlenecks.
1. Understanding Cloudflare Server-Timing Metrics
Modern applications leverage the W3C Server-Timing response header to communicate server-side execution stages to the client. When Cloudflare Server-Timing is enabled in your zone dashboard (under Speed > Optimization), Cloudflare automatically appends granular latency metrics:
cfEdge: The elapsed time in milliseconds spent inside Cloudflare's edge proxy infrastructure. This includes request parsing, SSL termination, firewall rule evaluation, and edge cache lookups.cfOrigin: The total time taken by Cloudflare to connect to, wait for, and receive headers from your backend origin web server. If this duration is high, the performance bottleneck lies within your backend application, database queries, or hosting provider.cfWorker: The CPU and execution time spent running Cloudflare Workers scripts and their asynchronous subrequests. A highcfWorkervalue indicates excessive CPU computation or blocking I/O inside your edge worker.cfRequestDuration: The overall lifecycle duration of the HTTP request through the Cloudflare proxy.
2. Decoding cf-cache-status Values
The cf-cache-status header indicates whether a request was satisfied from Cloudflare's edge cache or required an origin fetch:
- HIT: The resource was found in the edge cache and returned immediately with zero origin latency.
- MISS: The resource was not present in the edge cache, was retrieved from your origin server, and was stored in cache for subsequent visitors.
- DYNAMIC: The request was uncacheable by default (e.g., HTML documents, API endpoints, or responses with
Cache-Control: private, no-store), requiring an origin fetch. - BYPASS: Cloudflare bypassed the cache due to a specific Cache Rule, Page Rule, or cookie match (such as a WordPress logged-in cookie).
- EXPIRED: The resource was cached previously, but its Time-To-Live (TTL) expired, triggering an origin re-fetch.
- REVALIDATED: Cloudflare checked the cached asset against the origin using conditional headers (
If-Modified-SinceorETag), and the origin confirmed it is still fresh with an HTTP 304 response. - STALE: The resource was served stale from edge cache while asynchronous revalidation took place in the background (via
stale-while-revalidate).
3. Cloudflare Ray ID (cf-ray) and POP Location Analysis
Every request passing through Cloudflare receives a unique cf-ray header (e.g., 8d3c129e4a5b6c7d-SJC). The three-letter suffix corresponds to the IATA airport code of the Cloudflare Point of Presence (POP) data center that handled the TCP connection (such as SJC for San Jose, LHR for London Heathrow, or FRA for Frankfurt). Our analyzer automatically extracts these POP codes to verify whether user traffic is being routed to the closest regional edge data center or experiencing unexpected geo-routing latency.
4. Diagnosing Cloudflare 5xx Error Codes (520–526) in HAR Files
When an origin connection fails, Cloudflare returns specialized 5xx HTTP status codes. Inspecting HAR exports allows developers to isolate the root cause:
- 520 (Web Server Returned an Unknown Error): The origin server closed the connection prematurely or returned an empty, malformed header.
- 521 (Web Server Is Down): Cloudflare's TCP connection to the origin was refused on port 80 or 443.
- 522 (Connection Timed Out): Cloudflare could not complete the initial TCP handshake with the origin server within 15 seconds.
- 524 (A Timeout Occurred): Cloudflare successfully established a TCP connection, but the origin server failed to return HTTP response headers before the gateway timeout (default 100 seconds).
- 525 / 526 (SSL Handshake Failed / Invalid SSL): Cloudflare could not negotiate TLS with the origin or the origin certificate is untrusted/expired.
Frequently Asked Questions
Drop your .har file into the upload zone above or click to browse. The analyzer reads the file entirely in your browser, parses every recorded request, and renders a waterfall chart, header inspector, Cloudflare edge/origin/worker breakdown, and automated diagnostic Q&A with no server upload.
cfEdge measures the time spent inside Cloudflare's edge network processing the request. cfOrigin measures the round-trip latency and backend processing time waiting for your origin server to respond. cfWorker measures the execution duration of Cloudflare Workers scripts and subrequests. Inspecting these values reveals whether performance bottlenecks stem from the edge, origin backend, or serverless worker scripts.
Key cf-cache-status values include HIT (served directly from edge cache), MISS (not in cache, fetched from origin and stored), DYNAMIC (uncacheable or marked no-cache, fetched from origin), BYPASS (explicit rule or cookie bypassed cache), EXPIRED (TTL elapsed; re-fetched), and REVALIDATED (verified via If-Modified-Since with a 304 Not Modified response).
Yes. This HAR analyzer runs 100% client-side in your web browser. No files, session cookies, authorization headers, or private API payloads are ever transmitted to any remote server or stored in any database.
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