http-client

HTTP client ACT component — make outbound HTTP/HTTPS requests from a sandboxed WASM component.

Usage

just init   # first time: fetch WIT deps
just build  # build wasm component
just test   # run e2e tests

# Serve over HTTP
act run http_client.wasm

# Serve over MCP (e.g. for Claude Desktop)
act run --mcp http_client.wasm

# Direct call
act call http_client.wasm fetch --args '{"url": "https://httpbin.org/get"}'

Tool: fetch

Parameter	Type	Default	Description
url	string	required	URL to fetch
method	string	GET	HTTP method
headers	object	{}	Request headers
body	string	—	Text body (UTF-8)
body_json	any	—	JSON body (auto-serialized, auto-sets Content-Type)
body_raw	bytes	—	Raw binary body
timeout_ms	number	—	Request timeout in milliseconds
follow_redirects	boolean	true	Follow redirects (up to 10 hops)

Only one body type per request: body, body_json, or body_raw.

Examples

# Simple GET
act call http_client.wasm fetch --args '{"url": "https://httpbin.org/get"}'

# POST JSON
act call http_client.wasm fetch --args '{
  "url": "https://api.example.com/data",
  "method": "POST",
  "body_json": {"key": "value"},
  "headers": {"Authorization": "Bearer sk-..."}
}'

Response

Body is streamed as content chunks. First chunk includes metadata:

Metadata key	Type	Description
http-client:status	u16	HTTP status code
http-client:headers	HeaderMap	Response headers (CBOR-encoded)

HTTP error status codes (4xx, 5xx) are returned normally — check http-client:status.

Capabilities

Requires wasi:http — declared in act.toml.

License

MIT OR Apache-2.0