Why on-device
Every major website-audit tool — PageSpeed Insights, GTmetrix, DebugBear, Ahrefs, Semrush, Moz, Sitebulb Cloud, Lumar — is cloud-first. You submit a URL. Their servers fetch it, render it, run Lighthouse against it, and store the results under your account. That’s fine for public marketing sites. It’s broken for everything else:
- •Staging & pre-prod sites — exposing them to the public internet so a cloud tool can see them creates real risk. Most orgs don’t, so those sites simply don’t get audited.
- •Intranet apps — unreachable from the open internet by design. Every cloud auditor gives up.
- •Auth’d flows — cloud tools can’t log in as you. Paid tiers offer recorded scripts, but your credentials end up on their server.
- •Compliance-sensitive markets — healthcare, finance, government, EU with GDPR. “We uploaded the page to a third party to test it” is a compliance incident.
- •Personal data leakage — the HTML of an auth’d page contains user info, session tokens, CSRF values. Cloud tools claim they don’t retain; the safer posture is to not send it.
Compared to the status quo
| Tool | Runs on-device | Account required | Free page limit | Closest gap we fill |
|---|---|---|---|---|
| Tanvrit Auditor | ✓ | ✗ | Unlimited | — |
| PageSpeed Insights | ✗ | For API | 25k/day (secret sub-limits) | Runs cloud-only |
| GTmetrix | ✗ | ✓ (since Dec 2023) | 5 tests / month | Forced account + tiny cap |
| DebugBear | ✗ | ✓ | Paid from $39/mo | Monitoring pricing creep |
| Sitebulb | ~ Desktop paid | ✓ | 14-day trial then paid | Subscription not perpetual |
| Screaming Frog | ✓ Desktop | ✗ (free) | 500 URLs / crawl | Dated UI; low cap |
| Ahrefs / Semrush / Moz | ✗ | ✓ | None in free tier | Bundled into SEO suites |
| Unlighthouse | ✓ (CLI) | ✗ | Unlimited but ceilings @~200 | Node toolchain; Lighthouse-only |
| Pa11y | ✓ Self-host | ✗ | Unlimited | Node+Mongo setup; a11y only |
What on-device costs you
Honesty matters: on-device has real trade-offs.
- •Browser fetch CORS — the web version can’t fetch pages whose servers refuse cross-origin requests. The paste-HTML fallback covers those, and the desktop/mobile apps aren’t restricted.
- •No global-location testing — you can’t see how a site performs from Tokyo when you’re in London. That’s a cloud tool’s natural advantage.
- •Bigger desktop installer — an embedded Chromium is ~250 MB. One-time download; future updates are deltas.
Try it
Open the auditor in your browser, point it at a site, and check the network log. Nothing leaves your device except the URL you fetch.
Open auditor →