HAR File Viewer & Analyzer

Free online HAR file analyzer. Inspect network waterfalls, response timings, headers, and domain analytics with automatic sensitive data redaction.

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100% Client-Side Sandbox ProcessingProcessed locally inside browser memory with zero server storage.

Instant Real-Time ExecutionZero latency data manipulation powered by Web APIs.

Free & UnrestrictedNo accounts, subscriptions, or daily usage limits.

In-Depth Technical Guide

HAR File Analysis & Network Diagnostics: How to Debug Slow Web Requests

Learn how to analyze HTTP Archive (HAR) files, diagnose waterfall timing bottlenecks, inspect request headers, and isolate DNS or server-side latency drivers.

Read Full Guide (8 min read)

Technical Definition

What is HTTP Archive (HAR)?

A file that saves all the network requests your browser made, used by developers to fix slow websites.

View Glossary Definition

Technical Overview: How HAR File Viewer & Analyzer Works

The HAR File Viewer & Analyzer parses HTTP Archive (HAR 1.2) JSON files exported from browser DevTools, rendering waterfall request timelines, duplicate request warnings, domain performance analytics, automatic sensitive token/cookie redaction, and CSV export.

Parses the HAR JSON schema directly in client browser memory, calculating individual request timings: DNS resolution, TCP connection, SSL/TLS handshake, TTFB (Time to First Byte), and content download. Features paginated tables (50 items/page), duplicate GET request detection, and an automatic redaction toggle for Authorization tokens and Cookie headers.

Practical Examples & Usage

Inspecting Request Waterfall Timings

Input:HAR Log: GET /api/data (Status: 200, Total Time: 240ms)

Output:Timings: DNS: 15ms | Connect: 35ms | SSL: 40ms | TTFB (Wait): 120ms | Download: 30ms

Breaks down total request duration into granular network connection and server processing phases.

Real-World Applications & Use Cases

Diagnosing web page performance bottlenecks and identifying slow API endpoints causing high TTFB.
Auditing third-party advertising, analytics, and font scripts that block browser rendering.
Auditing duplicate network requests and uncompressed image assets across web applications.
Sanitizing and redacting authorization tokens and cookies before sharing HAR traces with external support teams.

How to use HAR File Viewer & Analyzer

Drag and drop a .har file, browse from disk, or paste raw JSON directly into the upload area.
Filter requests by status code (2xx, 3xx, 4xx, 5xx), HTTP method, or MIME resource type.
Toggle "Secrets Redacted" to automatically mask session cookies, authorization headers, and bearer tokens.
Navigate between "Requests Table", "Domain Analytics", and the visual "Timing Waterfall".
Click any request row to inspect its full headers, timings breakdown, and response body preview.

Edge Cases & Limitations

•HAR files frequently contain sensitive session cookies, bearer tokens, and form passwords; always use client-side tools with redaction enabled.
•Very large HAR files (>50MB containing thousands of requests) require adequate browser RAM for smooth timeline rendering.
•HAR logs reflect network conditions from the client machine where the capture occurred (bandwidth, CPU throttling).

Recommended Best Practices

•Enable the "Redact Sensitive Tokens" toggle before exporting CSV or sharing HAR data in bug tracking systems.
•Capture HAR files in Incognito/Private windows without browser extensions that inject extraneous network traffic.
•Inspect TTFB versus content download time to distinguish server processing latency from bandwidth congestion.

Privacy & Data Handling: How HAR File Viewer & Analyzer Treats Your Inputs

Processing Runtime

Sensitive inputs (passwords, tokens, document files, financial records, and personal parameters) are processed entirely within your local browser JavaScript and WebAssembly runtime.

Memory & Storage

Inputs and generated outputs remain strictly in your device volatile memory (RAM). Outlivo does not operate backend processing databases or logging servers for tool inputs. When you clear inputs or close the browser tab, data is immediately freed.

Network Transmission

Zero bytes of your input data, credentials, uploaded files, or generated documents are transmitted over the internet to Outlivo or any third-party server.

For complete transparency on data isolation and client sandboxing, visit our Privacy Policy or contact us via the Contact Center.

Frequently Asked Questions

Are sensitive cookies or credentials in my HAR file kept private?

Yes, 100%. The HAR file is parsed strictly inside your browser memory using HTML5 FileReader. No file content is uploaded to any server. Outlivo also provides an automatic redaction toggle to mask Authorization and Cookie headers.

Where do I get a .har file?

Open Chrome, Firefox, or Safari DevTools (F12), switch to the Network tab, perform your user flow, right-click any request in the list, and select "Save all as HAR with content".

Can it parse large HAR files without crashing the browser?

Yes. The analyzer uses pagination (50 items per page) and lazy inspection to maintain fluid 60fps scrolling and rapid analysis even on multi-megabyte HAR logs with hundreds of requests.

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