VerifyFetch is a JavaScript library that adds streaming integrity verification to file downloads in the browser, solving the memory problem of native fetch SRI which buffers entire files. It uses only 2MB of memory regardless of file size, supports resumable downloads, chunked fail-fast verification, multi-CDN failover, and a service worker mode that protects all fetches with zero code changes. Designed for large assets like AI models and WASM modules, it also includes CLI tools for generating SRI hashes and enforcing verification in CI/CD pipelines. The library addresses real supply chain attack vectors like the Polyfill.io CDN compromise.