wasmCloud Go

Go SDK, examples, and project templates for building WebAssembly components that run on wasmCloud v2.

• component (go.wasmcloud.dev/component) — the component SDK: write HTTP handlers with standard net/http types and compile them to WASI components with big Go via componentize-go. Two worlds are supported: a sync WASI P2 world (default, stock Go) and an async WASI P3 world (wasi:http@0.3.0, streaming bodies and native goroutine concurrency).
• component/nats — NATS-native messaging on wasmcloud:nats@0.1.0: core pub/sub and request-reply, JetStream, and JetStream KV, for what the portable component/messaging package cannot express — acknowledged delivery and redelivery, replay from an arbitrary stream position, and compare-and-swap on a KV revision. Every function on the interface is async, so a component importing it targets WASI P3.
• examples/components — runnable example components, each a standalone Go module.
• templates — starter templates for wash new.
• x — experimental libraries.

See BUILDING.md for the exact versions of Go, componentize-go, wit-bindgen and wash needed to build against a released SDK, and for how to build with no network at all.

Verifying a release

Each component/vX.Y.Z release attaches component-vX.Y.Z.zip, the module zip that go get downloads, and SHA256SUMS. Both carry Sigstore-signed SLSA build provenance. To verify a download with the GitHub CLI:

gh attestation verify component-v0.1.6.zip \
  --repo wasmCloud/go \
  --signer-workflow wasmCloud/go/.github/workflows/release-tag.yaml

--signer-workflow checks that the release workflow signed it, not just any workflow in the repository. go itself checks every module download against the Go checksum database. SECURITY.md also covers the release attestation and the go-airgap image.

Quickstart

wash new https://github.com/wasmCloud/go.git --name my-component \
  --subfolder templates/http-hello-world
cd my-component
wash dev

Examples

Example	Shows	WASI P3
http-server	HTTP routing and handlers via net/http
http-client	Outbound HTTP with http.RoundTripper
http-password-checker	A small JSON API
http-keyvalue-crud	HTTP CRUD over host-served wasi:keyvalue
http-otel	OpenTelemetry tracing via the host's wasi:otel plugin
http-p3-streaming	Async WASI P3: streaming echo + concurrent outbound fan-out	✅
nats-request-reply	Core NATS request-reply: a responder plus an HTTP gateway that calls it	✅
nats-jetstream-orders	JetStream delivery into KV, with ack/nak and compare-and-swap	✅
nats-kv-watch	Watching a JetStream KV bucket and rebuilding derived state	✅
nats-stream-replay	JetStream replay by sequence or range, and a pull consumer you settle yourself	✅

The unmarked examples build as sync WASI P2 components with stock Go. The marked ones target the async P3 world: http-p3-streaming asks for it directly, and the nats-* examples inherit it because every function on wasmcloud:nats@0.1.0 is async. componentize-go selects a patched Go toolchain for those automatically — see http-p3-streaming.

Migrating from wasmCloud v1

wasmCloud v2 removed wadm manifests, capability providers, and the wasmcloud:bus interface; the v1-era provider SDK (go.wasmcloud.dev/provider) and TinyGo component SDK line (v0.0.x) are no longer developed on main, though existing module versions keep resolving. See MIGRATING.md.