SensorFlow launches as self-hosted, open-source ClickHouse alternative to PostHog

What SensorFlow is

SensorFlow is a new event analytics stack that its developer has released as open-source, self-hosted software, announcing the project in a post on dev.to. It spans the full path from event collection through storage to querying and dashboards, with ClickHouse as the underlying engine. The code is on GitHub under an Apache-2.0 license, and the project publishes a public demo of its Superset dashboards.

The stated motivation is the per-event billing model common among managed analytics vendors: as traffic grows, so does the invoice, because charges track event volume. SensorFlow inverts that arrangement — you pay for the servers you run rather than for each event you capture.

How the stack is put together

The architecture is intentionally plain: an SDK sends events to a Go ingestion service, which writes them into ClickHouse; analysis then happens either through raw SQL or through Apache Superset dashboards.

Two details stand out. First, the Go collector is claimed to be wire-compatible with Sensors Data's SDKs, so teams already using that instrumentation may be able to keep it in place, after checking SDK versions, encryption settings, identity handling, property types and timestamps. The project notes it is independent and not affiliated with Sensors Data. Second, although the code carries an Apache-2.0 license, the locally installed demo is separate from production use: enabling real SDK ingestion requires obtaining a license and running an activation script. The announcement says no Kubernetes is needed.

ClickHouse was chosen, according to the post, because it is built for analytical workloads such as funnel and retention queries at scale.

How it compares with PostHog

The announcement includes a head-to-head comparison. SensorFlow is self-hosted only, whereas PostHog offers both cloud and self-hosted deployments. Its query model puts SQL and ClickHouse first, while PostHog centers on its product interface. Pricing is a flat annual license rather than usage-based. And SensorFlow ships none of the surrounding product suite — no session replay, feature flags or experiments, all of which PostHog provides.

The author frames the trade-off plainly: PostHog is the broader suite, while SensorFlow is the narrower option for teams that specifically want ClickHouse and full ownership of their stack.

On cost, the license is listed at $699 per year, with the first order currently discounted to $349 and the first month free. You supply the servers, and nothing is billed per event.

Why it matters

Usage-based pricing is now the default in product analytics, and it turns product success into a recurring cost that grows with adoption. A flat-license, self-hosted alternative reframes analytics spend as a fixed infrastructure line item, which matters most for high-volume products where event counts are large but the value derived from analytics does not necessarily scale with them.

Keeping raw event data on your own servers also matters for teams with compliance obligations or data-residency constraints that make managed analytics services awkward to adopt.

Two caveats are worth weighing. Every claim here — wire compatibility, cost comparisons, the feature table — comes from the developer's own announcement rather than independent testing or a second source. And the project blends permissively licensed code with a paid activation step for real ingestion, a hybrid readers should factor in when judging how open the stack is in daily use.