API reference

Reference pages for building on Open Meridian, taken from the code of each release. For a guided start, begin with Your first plugin. For the ideas behind these pages, read Plugins, roles and grants.

Page	What it covers
Command line	meridian: every command and flag, their defaults, exit codes and --json output. It covers installing a deployment, signing in, and uploading, launching and developing plugins.
Python SDK	The open-meridian package, imported as meridian: meridian.connect(), the Plugin object, its types, CallerMiddleware, and the exceptions it raises.
Typed operations	The workflow steps a plugin calls through its sidecar: each operation's Python method, gRPC rpc, role, parameters, result and errors.
Plugin manifest	[tool.meridian] in a plugin's pyproject.toml: its roles and page, and what a change to them takes.
plugin dev events	The JSON event stream of meridian plugin dev --json and meridian plugin events --json, for scripts and AI agents following a live plugin.

What is not here

Open Meridian has no order-routing or execution API in this release. The typed operations cover holdings ingestion and instrument resolution, and are read-only towards any brokerage.