workerd is a serverless edge runtime designed for executing lightweight, distributed functions at the network edge. It utilizes a V8-based JavaScript engine to provide fast startup and low memory overhead, while maintaining a WebAssembly-compatible execution environment that allows modules to run alongside JavaScript for high-performance computational tasks.
The runtime supports isolate-based multi-tenancy to run multiple independent execution contexts within a single process. It implements an event-driven execution model that triggers code based on network requests or scheduled events and includes support for privileged socket inheritance to operate under unprivileged user accounts.
The project covers a broad set of capabilities including serverless API development, AI inference deployment using GPU hardware and vector databases, and automated browser orchestration for web scraping. Additional functionality encompasses global state management via SQL databases and key-value stores, background job scheduling with message queues, and the delivery of static assets through a content delivery network.
Development is supported by a command-line interface for project management, custom build pipelines, and tools for pinning runtime behavior to specific dates to ensure consistency.