AWS CloudFront Access Log Parser

Parse AWS CloudFront W3C extended access log files locally in your browser. Computes Cache Hit Ratio % (Hit vs Miss vs RefreshHit), latency percentiles (P50/P95/P99), top requested static URIs, edge location POP distribution, and JSON/CSV summary exports. Runs entirely in your browser.

📂 Upload CloudFront .log File

CloudFront W3C Log Text

#Fields: date time x-edge-location sc-bytes c-ip cs-method cs(Host) cs-uri-stem sc-status cs(Referer) cs(User-Agent) cs-uri-query cs(Cookie) x-edge-result-type x-edge-request-id x-host-header cs-protocol cs-bytes time-taken x-forwarded-for ssl-protocol ssl-cipher x-edge-response-result-type
2026-07-24	14:00:01	IAD89-P1	4215	198.51.100.45	GET	d1111111111111.cloudfront.net	/assets/app.js	200	https://example.com/	Mozilla/5.0	-	-	Hit	ReqId_1111	d1111111111111.cloudfront.net	https	412	0.012	-	TLSv1.3	ECDHE-RSA-AES128-GCM-SHA256	Hit
2026-07-24	14:00:02	LHR61-P2	89104	203.0.113.88	GET	d1111111111111.cloudfront.net	/images/hero.webp	200	https://example.com/	Mozilla/5.0	-	-	Hit	ReqId_2222	d1111111111111.cloudfront.net	https	345	0.018	-	TLSv1.3	ECDHE-RSA-AES128-GCM-SHA256	Hit
2026-07-24	14:00:03	FRA56-P1	1240	198.51.100.99	GET	d1111111111111.cloudfront.net	/api/v1/user	200	https://example.com/	Mozilla/5.0	status=active	-	Miss	ReqId_3333	d1111111111111.cloudfront.net	https	210	0.185	-	TLSv1.3	ECDHE-RSA-AES128-GCM-SHA256	Miss
2026-07-24	14:00:05	IAD89-P1	0	192.0.2.14	GET	d1111111111111.cloudfront.net	/assets/app.js	304	https://example.com/	Mozilla/5.0	-	-	RefreshHit	ReqId_4444	d1111111111111.cloudfront.net	https	180	0.005	-	TLSv1.3	ECDHE-RSA-AES128-GCM-SHA256	RefreshHit
2026-07-24	14:00:08	SYD62-P1	482	198.51.100.12	GET	d1111111111111.cloudfront.net	/v1/orders	502	https://example.com/	Mozilla/5.0	-	-	Error	ReqId_5555	d1111111111111.cloudfront.net	https	220	0.950	-	TLSv1.3	ECDHE-RSA-AES128-GCM-SHA256	Error

Cache Hit Ratio60%

Total Requests5

Data Served0.09 MB

CDN Cache Result Breakdown

2Hits

1Refresh Hits

1Misses

1Errors

Latency Percentiles (ms)

18 msP50 (Median)

950 msP95

950 msP99 Tail

How to use

Drag & drop your raw AWS CloudFront access log file (.log or .txt) into the workspace, or paste log content directly.
Inspect the auto-calculated Cache Hit Ratio % (Hit vs Miss vs RefreshHit vs Error).
Review response time percentiles (P50, P95, P99) and status code distributions.
Examine top requested static paths and edge POP location activity.
Download JSON or CSV analysis reports for offline reporting.

Understanding the output

The parser evaluates standard AWS CloudFront W3C extended log fields. It computes cache efficiency metrics (Hit vs Miss), edge response latency percentiles, data transfer volumes (MB), and isolates slow origin requests.

Common issues & tips

•CloudFront log files usually begin with `#Version:` and `#Fields:` header lines. If header lines are missing, the parser defaults to standard W3C field ordering.
•CloudFront access log records use tab-separated fields ( ). Ensure copy-pasted log lines retain tab spacing.

Frequently asked questions

Are my CloudFront access logs uploaded to a server?: No. All log parsing and calculations take place 100% locally inside your web browser.
How is Cache Hit Ratio calculated?: Hit Ratio % = (Hit + RefreshHit) / Total Requests * 100. It measures the percentage of requests served from CloudFront edge caches without hitting your origin server.

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