Export a service as OpenRPC#

This example turns a JSON-RPC service in Smithy into an OpenRPC 1.3.2 document. It shows two ways: the build command with the openrpc plugin, and a library consumer.

model.smithy defines the service example.rpc#Calculator with three operations: subtract, history and clear. It uses @jsonRpc, @method, @examples and an @rpcError error.

Build with the CLI#

smithy-build.json selects model.smithy and the openrpc plugin for example.rpc#Calculator. Run from the repository root:

mise exec -- moon run apps/smithy --target native -- build --config examples/openrpc/smithy-build.json

The command prints nothing and exits with status 0. It writes the document to .dev/out/openrpc/source/openrpc/openrpc.json. The document has these values:

• openrpc is 1.3.2.

• info.title is Calculator, and info.version is 2026-10-21.

• methods has clear, history and subtract.

• components.schemas has the schemas that the methods reference.

Export from a program#

main.mbtx builds a smaller example#Calculator model, calls @openrpc.convert_result and prints the document. The program uses only published modules (moonrockz/smithy, moonrockz/smithy-validation/rpc and moonrockz/smithy-openrpc).

Run it from the repository root:

mise exec -- moonx scripts/test-validation-consumer.mbtx --openrpc native

The script copies the program into an isolated module and runs it. It checks that the output is an OpenRPC document with version 1.3.2 and one method. The output ends with these lines, and the exit status is 0:

Isolated openrpc passed: native
Audited 11 resolved manifests within the consumer's dependency profile

To run all four targets, and the checks of the built document, run mise run test:openrpc.