> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tell.rs/llms.txt
> Use this file to discover all available pages before exploring further.

# What is Tell?

> Product analytics, structured logs, and business signals — unified. Track what users do, what your app does, and what your business does. Query them together.

Tell is a unified analytics platform for product events, structured logs, and business signals. Track what users do, what your app does, and what your business does — then query them together. That's the point.

Most analytics tools show you *what* happened. Tell shows you *why*, because your product metrics, application logs, and external business data live in the same place. When signups drop, you don't switch between Mixpanel, Datadog, and a spreadsheet — you see the broken API call, the user journey, and the Shopify revenue impact in one query.

## What you can do

**Track user behavior.** Page views, signups, purchases, feature usage, funnels, retention — the things product and growth teams need. If you've used Mixpanel or PostHog, this is familiar. SDKs for JavaScript, Go, Swift, Flutter, Rust, and C++.

**Ingest structured logs.** Errors, warnings, debug info — with severity levels, service tags, and metadata. Not a sidecar. A full logging framework that shares the same SDK as your analytics, so you can correlate what users were doing when something broke.

**Connect business signals.** Pull metrics from GitHub, Shopify, and other services on a schedule. Track repository stars, store revenue, customer counts — anything that lives outside your app but matters to your business.

**Query everything.** SQL queries against ClickHouse. [Boards](/analytics/boards) with markdown and public sharing. CLI with live tail and instant queries. AI tools that answer questions about your data.

## How it works

You add a Tell SDK to your app. It sends product events and logs to a Tell server. Integrations pull in external data on a schedule. Everything flows through a pipeline that can route, filter, redact PII, and transform data before it lands in storage.

One SDK. One server. One binary.

```javascript theme={null}
// Product analytics — what users do
tell.track('purchase', { plan: 'pro', amount: 49.99 });

// Structured logs — what your app does
tell.log('warn', 'Payment retry failed', {
  service: 'billing',
  error: 'GATEWAY_TIMEOUT',
  attempt: 3,
  user_id: 'user-123'
});
```

Both calls go through the same SDK to the same server. Stored separately, queryable together.

## Why Tell

* **Stupid fast.** 64M events/sec on batched TCP. Rust pipeline with sub-millisecond latency.
* **One binary.** No containers. No Docker Compose. Runs on a VPS or your enterprise cluster.
* **Self-hosted.** Your data never leaves your servers. No cloud dependency. Tell Cloud is also available if you prefer managed.
* **Connect everything.** Product events, structured logs, business data. Query them together.

## Who it's for

Tell fits anywhere you have data in multiple places that should be in one.

* **Product and growth teams** — funnels, retention, DAU/WAU/MAU, and boards you own. The analytics you'd get from Mixpanel or PostHog, self-hosted and correlated with your logs.
* **Engineering teams** — debug production issues with the full picture: user events, application errors, and session context in one query.
* **Ecommerce and DTC** — unify checkout funnels, Shopify orders, campaign metrics, and backend logs. Answer "what changed?" when revenue drops.
* **Industrial and OT** — collect and forward logs from air-gapped networks. One Rust binary, deterministic performance, no cloud required.
* **Small teams** — stop paying for four tools that don't talk to each other.

## What's next

* [Concepts](/getting-started/concepts) — the three data protocols and how they work
* [Quickstart](/getting-started/quickstart) — send your first event in under 5 minutes
* [What to Track](/getting-started/what-to-track) — choosing between events, logs, and snapshots