Hadron
What it is
Hadron is a free, open-source, self-hosted distributed data storage and messaging system for ingesting events and running multi-stage workflows. Its Streams keep append-only records in partition order and support horizontal scaling. Pipelines coordinate stages over Stream data and can begin when an event matches a configured trigger. Exchanges handle ephemeral messages, while Endpoints expose general-purpose RPC handlers. Hadron uses the CloudEvents 1.0 model for Stream records, pipeline inputs and outputs, and ephemeral messages. It is designed for Kubernetes, installed with Helm and Kubernetes configuration resources. Retention can follow a configurable period that defaults to seven days or keep data indefinitely. Producers and Consumers can use any language; the project provides a Rust client and CLI. Components expose Prometheus metrics over HTTP. Token-based authentication creates JWTs signed by the Operator’s RSA key, with resource-level permissions.
For and against
For
- Append-only Streams with partition ordering
- Pipelines support event-triggered workflows
- CloudEvents 1.0 event format
- Prometheus metrics over HTTP
- Configurable or indefinite retention
Against
- Self-hosted Kubernetes deployment required
- External cluster access is still in progress
- Hosted Hadron Cloud is under construction
- Official client library listed for Rust
The verdict
Hadron combines event storage, workflow orchestration, messaging, and RPC around Kubernetes. Its self-hosted deployment and unfinished external access make the operating model important to evaluate.
Who it suits
Hadron suits teams building distributed applications with many microservices and event or telemetry signals. It is intended for self-hosted Kubernetes deployments, including local development.
On the record
- Access control
- Hadron authenticates with Tokens that produce JWTs signed with the Operator's private RSA key, with permissions configurable by resource.hadron-project.github.io · read 4 Oct 2026
- Authentication
- Hadron authentication uses Tokens that the Operator processes into JWTs stored in Kubernetes Secrets.hadron-project.github.io · read 11 Oct 2026
- CLI access limit
- The CLI documentation says access from outside the Kubernetes cluster is in progress.hadron-project.github.io · read 11 Oct 2026
- Client library
- The official clients page lists a Rust client and says client libraries for other languages are planned as Hadron matures.hadron-project.github.io · read 11 Oct 2026
- Clients
- Producers and Consumers can be written in any language, and the project maintains a shared Rust client and a CLI.hadron-project.github.io · read 4 Oct 2026
- Event format
- Hadron uses CloudEvents 1.0 for data entering and leaving the system.hadron-project.github.io · read 11 Oct 2026
- External access
- The CLI documentation says access from outside the Kubernetes cluster is in progress.hadron-project.github.io · read 4 Oct 2026
- Hosted service
- The quick start describes Hadron Cloud as under construction and the hosted, fully managed option.hadron-project.github.io · read 4 Oct 2026
- Hosted service status
- The quick start describes Hadron Cloud as under construction and hosted by the Hadron project team.hadron-project.github.io · read 11 Oct 2026
- Installation
- The quick start installs the Hadron Operator with Helm and requires Helm version 3.7.0 or later for OCI usage.hadron-project.github.io · read 11 Oct 2026
- Intended users
- The guide presents Hadron for distributed applications with many microservices and event or telemetry signals, and includes a local development use case.hadron-project.github.io · read 11 Oct 2026
- Kubernetes
- Hadron is designed to run in Kubernetes, and its Operator manages cluster lifecycle tasks including upgrades, horizontal scaling, and access control.hadron-project.github.io · read 11 Oct 2026
- Messaging and RPC
- Hadron describes Exchanges as ephemeral messaging between processes and Endpoints as general-purpose RPC handlers.hadron-project.github.io · read 11 Oct 2026
- Monitoring
- Hadron components expose Prometheus metrics over HTTP, with documented integration options including Prometheus scraping and the OTEL collector.hadron-project.github.io · read 4 Oct 2026
- Pipelines
- Pipelines orchestrate multi-stage workflows for Stream data, triggered when an event type matches a Pipeline trigger.hadron-project.github.io · read 11 Oct 2026
- Product
- Hadron is a distributed data storage system for ingesting events and working with them in multi-stage structured workflows.hadron-project.github.io · read 4 Oct 2026
- Purpose
- Hadron is a distributed event storage and messaging system for ingesting events and working with them in multi-stage workflows.hadron-project.github.io · read 11 Oct 2026
- Retention
- Stream data retention supports a configurable time policy that defaults to seven days, or an indefinite retain policy.hadron-project.github.io · read 4 Oct 2026
