The Resonate Server acts as a supervisor and orchestrator for Resonate Workers — that is, it provides reliability and scalability to applications built with a Resonate SDK.

Why does this component exist?

Popular programming languages like Python and TypeScript are not designed with abstractions that address distribution. To provide those abstractions at the application level (i.e. to enable API-like abstractions that simplify the implementation of reliable process to process message passing) the system needs a service that acts as both an orchestrator of messages and a supervisor of the processes sending them.

The Resonate Server is a highly efficient single binary that pairs with a Resonate SDK to provide those APIs.

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brew install resonatehq/tap/resonate

npm install @resonatehq/sdk

pip install resonate-sdk

A countdown as a loop. Simple, but the function can run for minutes, hours, or days, despite restarts.

import { Resonate, type Context } from "@resonatehq/sdk";

function* countdown(context: Context, count: number, delay: number) {
  for (let i = count; i > 0; i--) {
    // Run a function, persist its result
    yield* context.run((context: Context) => console.log(`Countdown: ${i}`));
    // Sleep
    yield* context.sleep(delay * 1000);
  }
  console.log("Done!");
}
// Instantiate Resonate
const resonate = new Resonate({ url: "http://localhost:8001" });
// Register the function
resonate.register(countdown);

Working example

from resonate import Resonate, Context
from threading import Event

# Register the function
@resonate.register
def countdown(ctx: Context, count: int, delay: int):
    for i in range(count, 0, -1):
        # Run a function, persist its result
        yield ctx.run(ntfy, i)
        # Sleep
        yield ctx.sleep(delay)
    print("Done!")


def ntfy(_: Context, i: int):
    print(f"Countdown: {i}")


# Instantiate Resonate
resonate = Resonate.remote()
resonate.start()  # Start Resonate threads
Event().wait()  # Keep the main thread alive

Working example

resonate dev

npx ts-node countdown.ts

python countdown.py

Activate the function with execution ID countdown.1:

resonate invoke countdown.1 --func countdown --arg 5 --arg 60

You will see the countdown in the terminal

npx ts-node countdown.ts
Countdown: 5
Countdown: 4
Countdown: 3
Countdown: 2
Countdown: 1
Done!

python countdown.py
Countdown: 5
Countdown: 4
Countdown: 3
Countdown: 2
Countdown: 1
Done!

After starting the function, inspect the current state of the execution using the resonate tree command. The tree command visualizes the call graph of the function execution as a graph of durable promises.

resonate tree countdown.1

Now try killing the worker mid-countdown and restarting. The countdown picks up right where it left off without missing a beat.

For more Resonate Server deployment information see the Set up and run a Resonate Server guide.

You can download and install the Resonate Server using Homebrew with the following commands:

brew install resonatehq/tap/resonate

This previous example installs the latest release. You can see all available releases and associated release artifacts on the releases page.

Once installed, you can start the server with:

resonate serve

You will see log output like the following:

time=2025-09-09T20:54:31.349-06:00 level=INFO msg="starting http server" addr=:8001
time=2025-09-09T20:54:31.349-06:00 level=INFO msg="starting poll server" addr=:8002
time=2025-09-09T20:54:31.351-06:00 level=INFO msg="starting metrics server" addr=:9090

The output indicates that the server has HTTP endpoints available at port 8001, a polling endpoint at port 8002, and a metrics endpoint at port 9090.

These are the default ports and can be changed via configuration. The SDKs are all configured to use these defaults unless otherwise specified.

The Resonate Server repository contains a Dockerfile that you can use to build and run the server in a Docker container. You can also clone the repository and start the server using Docker Compose:

git clone https://github.com/resonatehq/resonate
cd resonate
docker-compose up

If you don't have Homebrew, we recommend building from source using Go. Run the following commands to download the repository and build the server:

git clone https://github.com/resonatehq/resonate
cd resonate
go build -o resonate

After it is built, you can compile and run it as a Go program using the following command:

go run main.go serve

Or, you can run it as an executable using the following command:

./resonate server