Watermill by ThreeDotsLabs
Building event-driven applications the easy way in Go.
About Watermill
From the project's README at github.com/ThreeDotsLabs/watermill. Lightly cleaned for readability; for the full source see the upstream repo.
[](https://github.com/ThreeDotsLabs/watermill/actions/workflows/master.yml) [](https://pkg.go.dev/github.com/ThreeDotsLabs/watermill) [](https://goreportcard.com/report/github.com/ThreeDotsLabs/watermill) [](https://codecov.io/gh/ThreeDotsLabs/watermill)
Watermill is a Go library for working efficiently with message streams. It is intended for building event driven applications, enabling event sourcing, RPC over messages, sagas and basically whatever else comes to your mind. You can use conventional pub/sub implementations like Kafka or RabbitMQ, but also HTTP or PostgreSQL if that fits your use case. Goals
Easy to understand. Universal - event-driven architecture, messaging, stream processing, CQRS - use it for whatever you need. Fast (see Benchmarks). Flexible with middlewares, plugins and Pub/Sub configurations. Resilient** - using proven technologies and passing stress tests (see Stability). Getting Started
Health score breakdown
6-dimension composite. See methodology for formula and weights.
Adoption signals
Real-world usage data, pulled from each registry. The bigger the numbers, the more battle-tested the project.
| Signal | Value | Source |
|---|---|---|
| GitHub stars | 9.7k | github.com/ThreeDotsLabs/watermill |
| GitHub forks | 496 | github.com/ThreeDotsLabs/watermill |
Release & maintenance
Is this project actively maintained, or about to die? Check the recency of last commit and last release.
| Project age | 7.5 years | since Nov 2018 |
| Last commit | 17 days ago | Apr 20, 2026 |
| Releases shipped | 53 | last: 8 months ago |
Self-hosting cost across providers
Detected requirements: 4GB RAM, 40GB disk minimum. Cheapest plan per provider that meets the requirement.
| Provider | Plan | Specs | Monthly | |
|---|---|---|---|---|
| hetzner | CAX11 | 2c · 4GB · 40GB | $4.13 USD | Deploy → |
| vultr | VC2 | 1c · 1GB · 25GB | $5 USD | Deploy → |
| linode | Nanode 1GB | 1c · 1GB · 25GB | $5.12 USD | Deploy → |
| digitalocean | Basic Regular 1GB | 1c · 1GB · 25GB | $6 USD | Deploy → |
What people say on Hacker News
Ready to self-host Watermill?
Spin up a hetzner CAX11 (4GB RAM, 40GB disk) for $4.13/mo and follow the project's official install docs.
Data last refreshed May 7, 2026.
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