OnCatch by OnPath
The html2canvas killer

Most bug widgets capture a black rectangle on a WebGL page.

We don't. Below is the exact test we run against a live 3D scene — the system under test, the defects we plant, and the evidence we expect back. Then seven more stacks, each a different way to break a lesser widget. Run any of them yourself.

8
Stacks under test
20+
Hard-mode techniques validated
0
Black rectangles
QA test charter
System under test react-three-fiber product configurator
Planted defects — flip "break it"
  • !WebGL context loss (GPU reset)
  • !Texture load 404
  • !devicePixelRatio mismatch
What we capture
  • ✓The actual 3D scene, not a black rectangle
  • ✓Retina-sharp — honors devicePixelRatio
  • ✓No frame tear mid-animation
  • ✓GPU renderer string + WebGL console errors
Run this demo live

Live now at demo.oncatch.app — flip "break it" and submit a defect.

Seven more ways to break a widget.

Every stack embeds the real widget and a planted-defect toggle. File a defect, then watch it land in the public triage view — seconds later.

Vanilla HTML Strict CSP Booking iframe
Fintech landing
Proves: installs cleanly under a nonce-only CSP — the question every regulated buyer asks first — with a cross-origin booking iframe on the page.
2 planted defects Run it live →
Next.js 16 Stripe AI streaming
SaaS dashboard
Proves: stable capture under streaming-token churn, across a 10k-row virtualized table and a cross-origin Stripe Checkout iframe.
3 planted defects Run it live →
Vite · React 19 Service worker Canvas charts
Offline-first SPA
Proves: captures canvas charts at full fidelity and queues a report offline, flushing it the moment the network returns.
3 planted defects Run it live →
WordPress WooCommerce jQuery
WordPress + WooCommerce
Proves: survives heavy plugin and ad-tech script contention with no build step — the messiest real-world stack on the web.
3 planted defects Run it live soon
Astro 5 MDX Dark mode
Docs site
Proves: long-form DOM and theme-switch capture across static-first hydration with island components.
2 planted defects Run it live soon
Mapbox GL JS Raster tiles Live overlays
Logistics map
Proves: reads back a WebGL map with cross-origin tiles — the tainted-canvas trap — under live DOM-mutating overlays.
2 planted defects Run it live soon
Nuxt 3 · Vue RTL Stripe Elements
RTL storefront
Proves: mirrors a right-to-left layout correctly and handles the Stripe Elements iframe model in the Vue ecosystem.
2 planted defects Run it live soon
Your stack here?
Tell us the page in your product you'd least expect a widget to capture. We'll build the proof.
Request a stack

Four demos are live now at demo.oncatch.app — run one, flip "break it", submit a defect, and watch it land in the live triage view. The remaining stacks are in build.