Developer Performance Watch / Developer Tools

The official BSV TypeScript stack has merged a major update introducing VeriFast, an optional WebAssembly acceleration layer for Bitcoin Script validation, cryptographic operations, wallet functions, and large verification workloads.

The 12-commit update was merged into the ts-stack main branch on July 23. It preserves the existing synchronous SDK methods while allowing compatible operations to use a faster WebAssembly backend once that backend has been initialized.

The implementation uses adaptive routing rather than sending every operation through WebAssembly. An initial or small request continues through the existing JavaScript path. Once VeriFast is warm, scripts containing signature operations—or scripts larger than 100 bytes—can be directed to the WebAssembly verifier. Small calls remain in JavaScript when crossing the WebAssembly boundary would add more overhead than it removes.

The update also adds batch processing through a fixed worker pool. This allows transaction graphs, signature collections, and other larger workloads to be divided across warm workers rather than verified one item at a time. Supported accelerated operations include ECDSA signing and verification, public and symmetric BRC-42 key derivation, ProtoWallet signing and verification, authentication functions, and downstream wallet composition.

Project-reported tests on an Apple M3 Max found deterministic ECDSA signing approximately 28 times faster and signature verification approximately 18 times faster through the WebAssembly backend than through the existing JavaScript implementation. A packed batch of 250 signature verifications was reported as approximately 67 times faster when distributed across four warm workers, while a dependent graph of 250 signed transactions improved by approximately 3.6 times. These are development measurements from the pull request, not independent benchmarks or guarantees for every application environment.

The work also reduces the size of the browser-delivered verifier. The final pull-request summary places the complete classic-browser payload—wrapper, loader, and WebAssembly module—at 297,505 bytes, below a project-enforced 300,000-byte limit. The implementation supports Node ESM, CommonJS, browser ESM, classic UMD, browser workers, and BSV Blockchain network configurations including TeraTestNet and tstn.

Validation reported by the project covered 141 SDK test suites with 5,675 passing tests, five VeriFast suites with 39 tests, browser and Node module formats, worker-batch execution, and comparison of valid and corrupted transaction data against the JavaScript interpreter.

The review process also identified several issues involving differences between cold and warm validation behavior, browser packaging, SDK compatibility, worker recovery, and failure handling. A subsequent hardening commit addressed those concerns. The reviewer then approved the changes, stating that the review items had been verified as fixed and that additional artifact-hash, bundler, and worker testing closed the principal gaps. The pull request was subsequently merged with all required checks passing.

The update should currently be understood as a merged developer-stack milestone, not a completed public package release. The ts-stack repository has not yet published a formal GitHub release, and the review discussion noted that SDK and package-version alignment would need to be handled through the release process.

BSV TIMES read:
Performance at the developer-stack level matters because wallets, transaction services, identity systems, and high-volume applications repeatedly perform signature checks, key derivations, and Script validation. VeriFast’s adaptive design aims to accelerate heavier workloads without forcing every small operation across a WebAssembly boundary. The merge gives the official TypeScript stack a tested route toward faster cryptographic and transaction verification, although its practical reach will depend on the corresponding packages being formally released and adopted by applications.

Posted on July 24, 2026