HTTP Archive 1.2 · TTFB Waterfall · Zero Server Transmission

HAR File Viewer & Inspector

Troubleshoot API latency and network bottlenecks. Inspect HTTP headers, payloads, status codes, and phase-by-phase connection waterfalls directly in your browser.

Upload .har File

Client-only inspector · 0% data leaves your browser

Total Requests

Filtered: 4

Transferred Size

14.9 KB

Uncompressed: 48.1 KB

Longest Request

210 ms

Network latency

HTTP Status Codes

3 2xx·1 4xx

Status	Method	Resource / Path	Type	Size	Time
200	GET	/v1/auth/session api.speed-drain.com	Fetch/XHR	254 B	143 ms
200	GET	/assets/app.chunk.js speed-drain.com	JS	47.8 KB	68 ms
204	POST	/v1/telemetry analytics.speed-drain.com	Other	0 B	41 ms
404	GET	/api/v2/legacy/deprecations speed-drain.com	Fetch/XHR	64 B	210 ms

GET200 OK143 ms

https://api.speed-drain.com/v1/auth/session

Response Headers

content-type:application/json; charset=utf-8

cache-control:no-store, private

content-length:254

Request Headers

accept:application/json

user-agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64)

authorization:Bearer eyJhbGciOiJIUzI1Ni...

HTTP Archive (HAR) Architecture, Security & Diagnostics

Understanding the Network Timing Waterfall

Every entry in a HAR file logs high-precision timestamps for discrete network phases:

Blocked/Queued: Time spent waiting in the browser socket queue before a connection can be established (HTTP/1.1 limits to 6 connections per origin).
DNS Resolution: Time taken to query recursive name servers to resolve hostnames to IP addresses.
Connect & SSL: TCP three-way handshake ($SYN, SYN-ACK, ACK$) followed by TLS negotiation and certificate verification.
Waiting (TTFB): Time to First Byte. Latency between transmitting the request and receiving the first byte of response data from the upstream server.
Content Download: Time spent transferring response bytes across the network.

Security Notice: Sanitizing Sensitive Tokens

HAR files contain an unencrypted dump of everything the browser sent and received:

Session Cookies & Bearer Tokens: Headers like Authorization, Cookie, and Set-Cookie are stored in plaintext. Sharing raw HARs can allow attackers to hijack active user accounts.
Client-Side Processing: Our tool runs 100% locally in your browser memory. No network requests are dispatched to external servers, ensuring your API tokens remain private.

How to Export a HAR File in Modern Browsers

In Chrome, Edge, or Firefox, press F12 or right-click and select Inspect. Navigate to the Network tab, reproduce the network issue or API call, and click the down-arrow icon (Export HAR...) to save the session log for inspection.