Client SDKs

Client SDKs run outside the node — in a web app, script, or mobile app — and talk to it over JSON-RPC: call your application's methods, subscribe to context events, and drive the admin API.

They're distinct from the Service SDK, which is the code that runs inside the node (your app logic). If you're building a frontend or a tool, you want a client SDK below.

Calling a node from a client

JavaScript

import { MeroJs } from '@calimero-network/mero-js';

const client = new MeroJs({ nodeUrl: 'http://localhost:2528', apiKey: '…' });
await client.auth.authenticate();

const result = await client.rpc.call({
  contextId: '…',
  method: 'set',
  args: { key: 'hello', value: 'world' },
});

Python

from calimero_client_py import create_connection, create_client

connection = create_connection(api_url="http://localhost:2528")
client = create_client(connection)

result = client.get_peers_count()

Kotlin

import com.calimero.mero.Mero
import com.calimero.mero.MeroConfig
import com.calimero.mero.Credentials
import kotlinx.serialization.json.buildJsonObject
import kotlinx.serialization.json.put

val mero = Mero(MeroConfig(baseUrl = "https://your-node.example", /* tokenStore, … */))
mero.authenticate(Credentials(username = "alice", password = "s3cr3t"))

val post = mero.rpc.execute(
    contextId = "…",
    method = "get_post",
    argsJson = buildJsonObject { put("id", "42") },
)

Swift

import MeroKit

let mero = Mero(config: MeroConfig(
    baseURL: URL(string: "https://your-node.example")!,
    tokenStore: KeychainTokenStore()
))
try await mero.authenticate(Credentials(username: "alice", password: "s3cr3t"))

let post = try await mero.rpc.execute(
    contextId: "…",
    method: "get_post",
    argsJson: ["id": "42"]
)

These are just enough to show the shape — create a client, authenticate, call a method. Installation, the full API, event subscriptions (WebSocket / SSE), and the admin surface live in each SDK's reference below.

Full references

JavaScript — mero.js Pure-JS client for browser, Node, and edge. Full auth support.

Python — calimero-client-py Python client over a native Rust core. Automation, monitoring, scripting.

Kotlin — mero-kotlin Native Kotlin client for Android and JVM.

Swift — MeroKit Native Swift client for iOS and macOS.

| SDK | Language | Best for | | --- | --- | --- | | mero.js | TypeScript / JavaScript | Web apps, Node tools, admin UIs | | calimero-client-py | Python | Automation, monitoring, CI/CD | | mero-kotlin | Kotlin | Android and JVM apps | | MeroKit | Swift | iOS and macOS apps |

Related

• Service SDKs — write the app logic that runs in the node
• meroctl CLI — the command-line client
• Contexts and Identity