What Fanout is
Fanout is a single self-hosted binary for OpenTelemetry. One Go process accepts OTLP over gRPC and HTTP, publishes atomic Parquet batches with persistent trace indexes, runs DuckDB analytics and rollups, evaluates alert rules, serves a chat investigator and MCP tools, and hosts the browser client.
The point of that list is that it is one list. A conventional deployment of the same capability is a collector, a storage backend, a query layer, a dashboard service and an alertmanager, each with its own configuration, failure modes and upgrade cadence. Fanout is one process with one configuration and one thing to restart.
What it contains
Section titled “What it contains”| Part | What it does |
|---|---|
| OTLP ingest | Accepts traces, logs and metrics on gRPC and HTTP |
| Storage | Atomically publishes indexed Parquet batches to a local data directory |
| Query | Direct indexed trace reads plus in-process DuckDB SQL and rollups |
| Alerts | Evaluates persisted rules on a fixed interval against rollups |
| Investigator | A chat agent working from the same typed query tools |
| MCP server | Exposes those tools to an external agent |
| Browser client | Served by the same process, from the same binary |
What it is not
Section titled “What it is not”Fanout is not a hosted service, and it is not a collector. It sits where the backend sits: your SDKs or your existing Collector export to it.
It is also not a multi-tenant platform. Namespaces scope telemetry queries so one instance can hold several services’ data without them running together, but a namespace is not a user, an organisation or an authorisation boundary. An instance is a trust domain.
Who it is for
Section titled “Who it is for”Teams that want their telemetry on their own hardware, with a small enough operational surface that observability does not become its own on-call rotation. The reference deployment target is a single small VM.
Where it is in its life
Section titled “Where it is in its life”Fanout is pre-release. It changes without migration paths, and the shape of things that already run may still move. The capabilities page is the account of what is settled and what is not; it is worth reading before building anything durable on top.