Browser Support

VerifyKit targets modern browsers and runtimes that support WebAssembly and the Web Crypto API. This page lists minimum versions, required APIs, and known limitations.

Desktop Browsers

Browser	Minimum Version	Notes
Chrome	109+	Full support
Edge	109+	Chromium-based; same support as Chrome
Firefox	115+	Full support (ESR 115 is the minimum)
Safari	16.4+	Full support; requires macOS 13.3+ or iOS 16.4+

Mobile Browsers

Browser	Minimum Version	Notes
Chrome Android	109+	Full support
Safari iOS	16.4+	Full support; all iOS browsers use WebKit
Samsung Internet	21+	Chromium-based
Firefox Android	115+	Full support

Note: On iOS, all browsers (including Chrome and Firefox) use the WebKit engine. Safari iOS 16.4+ is the effective minimum for all iOS browsers.

Server-Side Runtimes

Runtime	Minimum Version	Notes
Node.js	20.19.0+	Full support for `@trexolab/verifykit-core` (headless verification)
Deno	2.0+	Supports WASM and Web Crypto; use npm specifiers for imports
Bun	1.0+	Supports WASM; compatible with the core package

The headless @trexolab/verifykit-core package works in all three runtimes. The React viewer (@trexolab/verifykit-react) requires a browser environment with DOM, Canvas, and Web Workers.

Required Web APIs

VerifyKit depends on the following browser APIs. All are available in the minimum browser versions listed above.

API	Used For
`WebAssembly`	Running the signature verification engine
`fetch`	AIA certificate fetching, revocation checking
`TextEncoder` / `TextDecoder`	String encoding/decoding for WASM interop
`DecompressionStream`	Decompressing PDF stream data (FlateDecode)
`crypto.subtle`	SHA-256 hashing for file fingerprints
`structuredClone`	Internal data handling
`Web Workers`	PDF.js page rendering (off main thread)
`Canvas 2D`	PDF page rendering
`Blob` / `URL.createObjectURL`	File handling, download, print

Polyfills

VerifyKit includes the following polyfill, which is loaded automatically:

Map.prototype.getOrInsertComputed — Required by pdfjs-dist 5.5+. This is a Stage 2 TC39 proposal not yet available in any browser. The polyfill is bundled and applied on import.

No other polyfills are required when targeting the minimum browser versions listed above.

PDF.js Worker Compatibility

VerifyKit pins a specific version of pdfjs-dist for the viewer. The PDF.js worker script must match this version exactly.

Use the legacy build of the worker (pdfjs-dist/legacy/build/pdf.worker.min.mjs) for maximum browser compatibility. The legacy build transpiles newer JavaScript syntax for older engines.
The non-legacy worker requires more recent browser versions and may not work in Safari 16.4 or Firefox ESR 115.

tsx

// Recommended: use the legacy worker
<VerifyKitProvider config={{
  workerUrl: 'https://unpkg.com/pdfjs-dist@5.5.207/legacy/build/pdf.worker.min.mjs',
}}>

Note: Do not upgrade pdfjs-dist independently of VerifyKit. The worker and main library must be the same version.

Known Limitations

Safari

OCSP/CRL via CORS: Safari's CORS handling is stricter than Chrome/Firefox. Direct OCSP and CRL fetches from the browser are blocked. Use the @trexolab/verifykit-plugin-revocation with a server-side proxy for revocation checking.
Web Worker scope: Safari does not support import in classic workers. The PDF.js worker must be loaded as a module worker or from a URL, which VerifyKit handles automatically.

Firefox

Private browsing mode: In private browsing, some storage APIs may be restricted. This does not affect verification but may impact the recent-files feature if it uses local storage.

Mobile Browsers

Memory constraints: Large PDFs (100+ pages, high-resolution scans) may cause memory pressure on mobile devices. Consider warning users or limiting file sizes in mobile-targeted applications.
Touch gestures: Pinch-to-zoom is supported via the usePinchZoom hook. Text selection on touch devices may behave differently than on desktop.

Node.js

No Canvas: Node.js does not include a Canvas implementation. The headless @trexolab/verifykit-core package works without Canvas (it only performs signature verification, not rendering). If you need server-side rendering, use a Canvas polyfill like canvas (node-canvas).
No Web Workers: PDF rendering in Node.js does not use workers. This is not relevant for headless verification.

Internet Explorer

Internet Explorer is not supported. VerifyKit requires WebAssembly, ES2022+ features, and module syntax, none of which are available in IE.