Analyze HAR network captures — waterfall timing, payload sizes, failed requests. Find the 3-second render blocker in minutes — local parsing, free, no signup.
Content reviewed October 2026 · About Toolzum
Analyze log files — error grouping, level counts, time clustering. Find the 3am spike cause in minutes — local parsing, free, no signup.
Profile JSON payload weight — byte size, key counts, nesting depth, and heavy branches. Find the 2 MB field bloating responses — local analysis, free, no signup.
Parse Set-Cookie headers into structured JSON, or analyze cookie security flags (Secure, HttpOnly, SameSite, expiry). Flag missing Secure, HttpOnly, and SameSite attributes — free, local, no signup.
Peek inside any ZIP — list contents with sizes before extracting anything. Verify a 500 MB download's contents first — local fflate parsing, free, no signup.
Measure exact elapsed time since any moment — days, hours, minutes live. Track 100 days sober to the second — free, local, no signup.
Sort by time: DNS, connect, TTFB, and content-download phases split per request. One 3-second font or API call usually dominates — optimize that first.
4xx/5xx entries list with URLs and bodies where captured. CORS failures show as opaque — check the console alongside.
Scrub first: HARs contain cookies, tokens, and POST bodies. Sanitize or share with trusted parties only — the analyzer itself uploads nothing.
No — parsing runs locally in your browser. HAR contents never leave your device — still sanitize before sharing exports.
Total time per entry sums wait + receive only; body sizes of -1/unknown count as 0 bytes and are listed under Skipped/approximated; the text waterfall draws 1 # per 20ms capped at 30 characters, with URLs cut to 40 characters.
Log File Analyzer
Analyze log files — error grouping, level counts, time clustering. Find the 3am spike cause in minutes — local parsing, free, no signup.
HTTP Header Analyzer
Analyze HTTP request and response headers — detect security headers, review formatting, and inspect value structure. Code never leaves your device — formatting and validation run locally in your browser.