WIT interfaces.

WASI 0.2 Component Model interfaces. Type-safe contracts between host and guest.

Explore the details

Make the boundary explicit.

The component exports one data shape; the host accepts another. Matching their types closes the connection.

Interactive example

COMPONENT EXPORTimage:processstring

HOST IMPORTobjects:writelist<u8>

Type mismatch

Choose list<u8> to match the host's byte-list input.

interface objects {
  write: func(data: list<u8>);
}

What is WIT

WIT (WASM Interface Types) is the contract language for the Component Model. It defines the types, functions, and resources that a guest module can import from the host and export to callers.

Hives implements the full WASI 0.2 surface plus platform-specific extensions for storage, queues, config, and secrets. Every interface is versioned, documented, and backward-compatible.

Guest exports

handler, lifecycle hooks, health checks

Host imports

HTTP, KV, SQL, queues, secrets, clock

Versioning

Semantic, additive-only, never breaking

Core interfaces

wasi:httpIncoming and outgoing HTTP requests. Typed headers, streaming bodies, and TLS configuration.

wasi:keyvalueAtomic key-value operations. Get, set, delete, list, and compare-and-swap with TTL support.

hives:queuesPublish and consume messages. Dead-letter routing, batching, and at-least-once delivery.

Explore the spec

Full WIT definitions, type documentation, and compatibility tables.

Read the docs →