---
published: true
id: json-rpc
title: JSON-RPC
description: Knowledge captured in João Lopes' learning graph.
tags:
- protocol
- web
locale: en
resource: https://joaolopes.dev.br/knowledge/concepts/en/json-rpc/
created: '2026-03-28'
---

# JSON-RPC
A lightweight remote procedure call protocol encoded in JSON, where a client sends a method name and parameters and the server returns a result.

## Definition
JSON-RPC is a stateless, transport-independent remote procedure call protocol that uses JSON as its data format. A client sends a JSON object with a method name and parameters; the server executes the method and returns a JSON result. MCP (Model Context Protocol) uses JSON-RPC as its transport layer: the agent runtime sends tool call requests as JSON-RPC messages to MCP servers, which execute the tools and return results.

## Source
- [JSON-RPC - Wikipedia](https://en.wikipedia.org/wiki/JSON-RPC)
- [JSON-RPC 2.0 Specification](https://www.jsonrpc.org/specification)

## Related
- [MCP](/concepts/en/mcp.md)